The  ovarian fossa  is a shallow depression on the lateral wall of the  pelvis , where in the  ovary  lies.


This ovarian fossa has the following boundaries:


This article incorporates text in the  public domain  from  page 1254  of the 20th edition of   Gray's Anatomy   (1918)


The  parametrium  is the fibrous and fatty  connective tissue  that surrounds the  uterus . [ 1 ]  This  tissue separates the supravaginal portion of the  cervix  from the  bladder . The parametrium lies in front of the cervix and extends laterally between the layers of the  broad ligaments . It connects the uterus to other tissues in the  pelvis . [ 1 ]   It is different from the  perimetrium , which is the outermost layer of the uterus.


The  uterine artery  and  ovarian ligament  are located in the parametrium.


An associated form of  pelvic inflammatory disease  is inflammation of the parametrium known as  parametritis .


The  paroophoron  (of Johnson;  pl. :  paroophora ) consists of a few scattered rudimentary tubules, best seen in a child, situated in the  broad ligament  between the  epoöphoron  and the  uterus . [ 1 ]  Named for the Welsh anatomist David Johnson who originally described the structure at the  University of Wales ,  Aberystwyth .


It is a remnant of the  mesonephric tubules [ 2 ]  and is   homologous  to the male  paradidymis .


A  pelvic kidney , also known as an  ectopic kidney , is a normal  kidney  located in the  pelvis , instead of the  abdomen . This occurs when a kidney does not ascend from its original location in the pelvis to its final location during  prenatal development . They usually present no  symptoms , but can increase risk of certain illnesses and healthcare problems.


Often, a person with a pelvic kidney will go through their whole life not even knowing they have a pelvic kidney.


While symptoms are uncommon, some people with a pelvic kidney may experience abdominal or back pain, fever,  hematuria , high blood pressure, or a burning sensation while urinating. [ 1 ]


Typically, the kidney functions normally despite being in the wrong location. [ 2 ]  However, it can develop complications. [ 3 ]  A pelvic kidney can make it more difficult to diagnose  kidney infections  and  kidney cancer . [ 4 ]  The  renal artery  and the  renal vein  may be stretched if they remain attached to the normal locations on the  abdominal aorta  and the  inferior vena cava , which can lead to illness. [ 4 ]


A pelvic kidney may increase one's risk of developing  urinary tract infections  and  kidney stones . The condition may also result in  hydronephrosis . Children with a pelvic kidney may need to wear certain protective equipment while playing sports to prevent injuries. [ 1 ]


In the development of the  human embryo , the metanephric kidneys fail to ascend and usually remain at the brim of the  pelvis . This clinical scenario may present no signs or symptoms and the kidneys may function normally. It is associated at times with  Müllerian dysgenesis . [ citation needed ]


A pelvic kidney is discovered on newborn kidney  ultrasound screening . It may also be detected if complications arise later in life for this or a completely different reason, and during investigations. [ citation needed ]


Between 1 in 2,200 and 1 in 3,000 people may have a pelvic kidney. [ 2 ]


A pelvic kidney is also known as an ectopic kidney. [ 4 ]


Penile pain  refers to pain in the  penis  of  human  or otherwise.


Priapus , a minor  Greek  god of fertility, [ 1 ]  is marked by his oversized, permanent  erection , which gave rise to the medical term  priapism .


The  perimetrium  (or  serous coat of uterus ) is the outer  serosal  layer of the  uterus , derived from the  peritoneum  overlying the  uterine fundus , and can be considered a  visceral peritoneum .  It consists of a superficial layer of  mesothelium , and a thin layer of  loose connective tissue  beneath it.


Anteriorly, the perimetrium covers the fundus and upper body of the uterus until it meets the superoposterior surface of the adjacent  urinary bladder , resulting in a concave fold of peritoneum called the  vesicouterine pouch .  Posteriorly, the perimetrium covers the entire surface of the uterus deep down to the  cervix , where it then folds back onto the adjacent  rectum  to form the  rectouterine pouch , the lowest gutter of the  peritoneal cavity .  Laterally, the perimetrium blends into the  serosae  of the  broad ligaments . [ 1 ] [ 2 ]


The  perineal raphe  is a visible line or ridge of tissue on the body that extends from the  anus  through the  perineum  to the  scrotum  (male) or the  vulva  (female). It is found in both males and females, arises from the fusion of the  urogenital folds , and is visible running medial through anteroposterior, to the anus where it resolves in a small knot of skin of varying size.


In males, this structure continues through the midline of the scrotum (scrotal raphe) and upwards through the posterior midline aspect of the  penis  ( penile raphe ). It also exists deeper through the scrotum where it is called the  scrotal septum .  It is the result of a  fetal  developmental phenomenon whereby the scrotum and penis close toward the midline and fuse. [ 1 ]


This article incorporates text in the  public domain  from  page 1237  of the 20th edition of   Gray's Anatomy   (1918)


This  anatomy  article is a  stub . You can help Wikipedia by  expanding it .


The  perineal sponge  is a spongy cushion of  tissue  and  blood vessels  found in the lower  genital area  of  women . It sits between the  vaginal opening  and  rectum  and is internal to the  perineum  and  perineal body . [ citation needed ]


The perineal sponge is composed of  erectile tissue ; during  arousal , it becomes swollen with  blood  compressing the outer third of the vagina along with the  vestibular bulbs  and  urethral sponge  thereby tightening the vagina and increasing stimulation for the vagina and a penis, if involved. [ 1 ]


The perineal sponge is erogenous tissue encompassing a large number of  nerve endings , and can, therefore, be stimulated through the back wall of the  vagina  or the top wall of the rectum. [ 2 ]


Perinephritis  is an infection of the surroundings of the kidney either right or left. It can be the result of extravasated infiltration of the bacteria out of the renal pelvis ( pyelonephritis ) or a result of another kidney infection. The consequences include the infection of the neighbouring organs (for example  transverse colon [ 1 ] ) or  retroperitoneum , and/or  hypertension . [ 2 ] [ 3 ] [ 4 ]   Perirenal abscess  also may occur. [ 3 ]


The  pre-prostatic urethra  is one of the four parts of the  male urethra . The pre-prostatic urethra is also known as the intramural urethra, as it is the portion of the  urethra  which passes almost vertically through the wall of the  urinary bladder , before it enters the  prostate  gland.


Both the length and diameter of the pre-prostatic urethra vary depending on whether the bladder is filling or emptying. The length varies between 0.5 cm and 1.5 cm. [ 1 ]


The  prostatic ducts  (or  prostatic ductules ) open into the floor of the  prostatic portion of the urethra , and are lined by two layers of  epithelium , the inner layer consisting of columnar and the outer of small cubical cells.


Small  colloid  masses, known as  amyloid  bodies are often found in the gland tubes.


They open onto the  prostatic sinus .


This article incorporates text in the  public domain  from  page 1253  of the 20th edition of   Gray's Anatomy   (1918)


On either side of the  urethral crest  is a slightly depressed  fossa , the  prostatic sinus , the floor of which is perforated by numerous apertures, the orifices of the  prostatic ducts  from the lateral lobes of the  prostate .


This article incorporates text in the  public domain  from  page 1234  of the 20th edition of   Gray's Anatomy   (1918)


The  prostatic urethra ,  the widest and most dilatable part of the  urethra  canal, is about 3 cm long.


It runs almost vertically through the prostate from its base to its apex, lying nearer its anterior than its posterior surface; the form of the canal is spindle-shaped, being wider in the middle than at either extremity, and narrowest below, where it joins the  membranous portion .


A transverse section of the canal as it lies in the  prostate  is horse-shoe-shaped, with the convexity directed forward.


The keyhole sign, in ultrasound, is associated with a dilated bladder and prostatic urethra.


A  prosthetic testicle  is an  artificial replacement  for a  testicle  lost through  surgery  or  injury. Consisting of a plastic ovoid manufactured from  silicone rubber , and either solid, or filled with a  salt solution  and implanted in the  scrotum , a prosthetic testicle provides the appearance and feel of a  testis  and prevents  scrotum  shrinkage. It is also commonly used in  female-to-male sex reassignment surgery . [ 1 ] [ 2 ] [ 3 ]


The list shows testicular implants available in the market in 2020. [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ]


Pseudodyssynergia  (or  detrusor sphincter  pseudodyssynergia) is an  urological  condition involving contraction of the  male  or  female external sphincter  during  voiding . [ 1 ]


Coordination between the sphincter and  detrusor  is thus lost. [ 2 ]


The  renal columns ,  Bertin columns , or  columns of Bertin , a.k.a.  columns of Bertini  are extensions of the  renal cortex  in between the  renal pyramids . They allow the cortex to be better anchored. (Cortical extensions into the medullary space.)


Each column consists of lines of blood vessels and urinary tubes and a fibrous material.


A hypertrophied renal column (or  renal pseudotumor ) may be differentiated from an actual  renal tumor  with the help of a  DMSA scan . The scan will show the area as one with normal activity if it is a pseudotumor or will show decreased uptake if it is a cystic or solid renal mass.


The  renal cortex  is the outer portion of the  kidney  between the  renal capsule  and the  renal medulla . [ 1 ]  In the adult, it forms a continuous smooth outer zone with a number of projections ( cortical columns ) that extend down between the  pyramids . It contains the  renal corpuscles  and the  renal tubules  except for parts of the  loop of Henle  which descend into the  renal medulla . It also contains blood vessels and  cortical collecting ducts .


The renal cortex is the part of the  kidney  where  ultrafiltration  occurs. [ 2 ]   Erythropoietin  is produced in the renal cortex. [ 3 ]


The  renal hilum  or  renal pedicle  is the recessed central fissure of the  kidney  where its vessels,  nerves  and  ureter  pass. The medial border of the kidney is concave in the center and convex toward either extremity; it is directed forward and a little downward. Its central part presents a deep longitudinal fissure, bounded by prominent overhanging anterior and posterior lips. This fissure is a  hilum  that transmits the vessels, nerves, and ureter. From anterior to posterior, the  renal vein  exits, the  renal artery  enters, and the  renal pelvis  exits the kidney.


On the left hand side the hilum is located at the  L1 vertebral  level and the right kidney at level L1-2. The lower border of the kidneys is usually alongside L3.


The superior, middle, and inferior vessels enter or leave the hilum of kidney: from anterior to posterior is renal vein, renal artery and renal pelvis, respectively.


This article incorporates text in the  public domain  from  page 1219  of the 20th edition of   Gray's Anatomy   (1918)


Renal segmental hypoplasia   is a kidney with a partially developed or  atrophic   renal cortex . [ 1 ]


Ask-Upmark kidneys are a cause of  secondary hypertension  that can be curable. [ 2 ]


It is thought to be  congenital  or the consequence of  vesicoureteral reflux . [ 2 ]
in IVU "Slit scar" is seen.


The  renal sinus  is a cavity within the  kidney  which is occupied by the  renal pelvis ,  renal calyces , blood vessels, nerves and fat. The renal hilum extends into a large cavity within the kidney occupied by the renal vessels, minor renal calyces, major renal calyces, renal pelvis and some  adipose tissue . [ 1 ]


The  rete testis  ( / ˈ r iː t i   ˈ t ɛ s t ɪ s /   REE -tee  TES -tis ;  pl. :  retia testes ) is an  anastomosing  network of delicate  tubules  located in the hilum of the  testicle  ( mediastinum testis ) that carries  sperm  from the  seminiferous tubules  to the  efferent ducts . It is the  homologue  of the  rete ovarii  in females. [ 1 ]  Its function is to provide a site for fluid reabsorption.


The rete testis is the network of interconnecting tubules where the  straight seminiferous tubules  (the terminal part of the  seminiferous tubules ) empty. It is located within a highly vascular  connective tissue  in the  mediastinum testis . [ 2 ]  The  epithelial cells  form a single layer that lines the inner surface of the tubules. These cells are  cuboidal , with  microvilli  and a single  cilium  on their surface. [ 3 ]


In the  development of the urinary and reproductive organs , the  testis  is developed in much the same way as the  ovary , originating from  mesothelium  as well as  mesonephros . Like the ovary, in its earliest stages it consists of a central mass covered by a surface epithelium. In the central mass, a series of cords appear. These cords run together toward the future  hilum  and form a network that ultimately becomes the rete testis.


It appears the function of the rete testis is to mix the sperm as they leave the seminiferous tubules. Sperm leave the seminiferous tubules in the dilute secretions of Sertoli cells. The rete testis does modify the luminal fluids with a limited amount of secretion and reabsorption, but their primary function is to mix and transport the sperm into the efferent ductules, where the major function is reabsorption of about 95% of the fluid, which increases the sperm concentration prior to entering the epididymis.


Rete tubular ectasia  is a disorder of the rete testis characterized by multiple benign  cysts .


English uses the  Neo-Latin  name for the structure, which simply means " network  of the  testis ".


The  seminal tract  is a part of the  male reproductive system  and consists of  seminiferous tubules  ( tubuli seminiferi recti ,  rete testis ,  efferent ducts ),  epididymides   ( appendix ),  Vas deferens  ( ampulla ) and  ejaculatory ducts .


The  septa testis  are fibrous partitions of the testis dividing the testis into compartments - the  lobules of the testis . The septa are formed by extensions of the  tunica albuginea  - the dense fibrous connective tissue surface covering of the testis - into the substance of the testis. The septa converge towards the  mediastinum testis . [ 1 ]


In  human male   anatomy , the  septum of the penis  or  penile septum  refers to the  fibrous  junction ( septum ) between the two  corpora cavernosa  of the  human penis . The  tunica albuginea  of the penis forms a thick fibrous coat to the  spongy tissue  of the corpora cavernosa and  corpus spongiosum . [ 1 ]  The two corpora cavernosa are surrounded by a strong fibrous envelope consisting of superficial and deep fibers. The superficial or outer fibers are  longitudinal  in direction, and form a single tube which encloses both corpora; the deep or inner fibers are arranged circularly around each corpus and meet in the center. By their junction in the  median plane , the inner fibers form the intercavernous septum of the penis. [ 2 ] [ 1 ]


This septum is composed of multiple strands of  connective tissue , similar to that of the  tunica albuginea . [ 3 ]  It is thick and complete behind, where the corpora cavernosa become independent and form separate  crura , [ 3 ]  but it is imperfect in the front, where it consists of a series of vertical bands arranged like the teeth of a comb; it is therefore named the  septum  pectiniforme  ( pectinate  septum). [ 4 ]


This article incorporates text in the  public domain  from  page 1248  of the 20th edition of   Gray's Anatomy   (1918)


A  Sertoli cell nodule  is a  benign   proliferation  of  Sertoli cells  that arises in association with  cryptorchidism  (undescended testis). [ 1 ]   They are not composed of a clonal cell population, i.e.  neoplastic ; thus, technically, they should not be called an  adenoma . [ 2 ]


Sertoli cell nodules are unencapsulated nodules that consist of: [ 2 ] [ 3 ] [ 4 ]


Sialuria  is a group of disorders resulting in an accumulation of free  sialic acid . [ 1 ]  One type, known as the Finnish type or  Salla disease  has been described in northeastern Finland and is due to a mutation in gene SLC17A5 on chromosome 6q4-15. [ 1 ]  The "French type sialuria" ( Online Mendelian Inheritance in Man  (OMIM):  269921 ), [ 1 ]  is a very rare condition presenting in infancy with  failure to thrive ,  yellowish skin ,  large liver ,  low blood count , recurrent chest infections,  bowel upsets , dehydration and characteristic facial features. [ 2 ] [ 3 ] [ 4 ]


Spermaturia  is condition characterized by the presence of  sperm  in the  urine . [ 1 ]


It can be observed in males of other species and then sometimes diagnosed in  veterinary medicine . [ 2 ]  The cause is most often a  retrograde ejaculation . It may be  physiological  during  urination  after  coitus  (postcoital urination). [ citation needed ]


An irrational belief that one is experiencing spermaturia is a common symptom of  Dhat syndrome . [ 3 ]


The  subcutaneous tissue of penis  (or  superficial penile fascia ) is continuous above with the  fascia of Scarpa , and below with the  dartos tunic  of the  scrotum  and the  fascia of Colles .


It is sometimes just called the "dartos layer". [ 1 ]


It attaches at the intersection of the body and glans. [ 2 ]


The term "superficial penile fascia" is more common, but "subcutaneous tissue of penis" is the term used by  Terminologia Anatomica .


A  supernumerary  kidney  is an additional kidney to the number usually present in an organism. This often develops as the result of splitting of the nephrogenic  blastema , or from separate  metanephric blastemas  into which partially or completely reduplicated ureteral stalks enter to form separate capsulated kidneys; in some cases the separation of the reduplicated organ is incomplete (fused supernumerary kidney).


Less than a hundred cases are known of one or two supernumerary kidneys.


The  supravaginal portion of the cervix  (also known as the  uterine portion of the cervix ) is separated in front from the  bladder  by fibrous tissue ( parametrium ), which extends also on to its sides and lateralward between the layers of the  broad ligaments .


The  uterine arteries  reach the margins of the cervix in this fibrous tissue, while on either side the  ureter  runs downward and forward in it at a distance of about 2 cm. from the cervix.


Posteriorly, the supravaginal cervix is covered by peritoneum, which is prolonged below on to the posterior vaginal wall, when it is reflected on to the  rectum , forming the  recto-uterine pouch .


It is in relation with the rectum, from which it may be separated by coils of  small intestine .


This article incorporates text in the  public domain  from  page 1259  of the 20th edition of   Gray's Anatomy   (1918)


The  theca externa  is the outer layer of the  theca folliculi . It is derived from connective tissue, the cells resembling  fibroblasts , and contains  abundant  collagen . [ 1 ]  During ovulation, the surge in  luteinizing hormone  increases  cAMP  which increases  progesterone  and  PGF2α  production. The PGF2α induces the contraction of the  smooth muscle  cells of the theca externa, increasing intrafollicular pressure. This aids in rupture of the mature  oocyte , or immature oocyte at the germinal vesicle stage in the canine, along with  plasmin  and  collagenase  degradation of the follicle wall.


Theca interna  cells express  receptors  for  luteinizing hormone  (LH) to produce  androstenedione , which via a few steps, gives the  granulosa  the precursor for  estrogen  manufacturing. [ 1 ]


After rupture of the mature  ovarian follicle , the theca interna cells differentiate into the  theca lutein cells  of the  corpus luteum . Theca lutein cells secrete  androgens [ 2 ]  and  progesterone . Theca lutein cells are also known as small luteal cells. [ 2 ]


The  thin segment  is a part of the renal tubule found between the  proximal  and  distal tubules . The renal tubule and the  renal corpuscle  together comprise the  nephron . [ 1 ]


The thin segment is described as a U-shaped band, consisting of the two continuous parts:


Both limbs of the loop of Henle are lined with the  simple squamous epithelium . [ 2 ]  Their main function is to regulate the levels of  water  and solutes in the primary  urine . The  basement membrane  of the thin limb in humans has very uniform nodular thickenings that form a network that surrounds the tubule and acts as a support structure that is homologous to the collenchyma in  plants . Smith, RA et al. (Arch Pathol Lab Med Vol 108, May 1984) have designated these nodules "Belliveau Bodies" after Robert Belliveau the pathologist who originally described these structures. [ 3 ]


Tight hymenal ring  is a disorder of the  hymen , characterized by a rigid hymen and tight  introitus , whether acquired or congenital. It excludes an  imperforate hymen .


The individual with tight hymenal ring might face difficulty in inserting a tampon into the  vagina  or having intercourse. The condition can be relieved by  outpatient surgery  or manual dilation. [ 1 ]


From the internal surface of the fibrous envelope of the  corpora cavernosa penis , as well as from the sides of the septum, numerous bands or cords are given off, which cross the interior of these corpora cavernosa in all directions, subdividing them into a number of separate compartments, and giving the entire structure a spongy appearance.


These bands and cords are called the  trabeculae of corpora cavernosa of penis , and consist of white fibrous tissue, elastic fibers, and plain muscular fibers. In them are contained numerous arteries and nerves.


The component fibers which form the trabeculae are larger and stronger around the circumference than at the centers of the  corpora cavernosa ; they are also thicker behind than in front.


The interspaces (cavernous spaces), on the contrary, are larger at the center than at the circumference, their long diameters being directed transversely.


They are filled with blood, and are lined by a layer of flattened cells similar to the endothelial lining of veins.


This article incorporates text in the  public domain  from  page 1250  of the 20th edition of   Gray's Anatomy   (1918)


The fibrous envelope of the  corpus cavernosum urethrae  is thinner, whiter in color, and more elastic than that of the  corpora cavernosa penis . It is called the  trabeculae of corpus spongiosum of penis .


The trabeculae are more delicate, nearly uniform in size, and the meshes between them smaller than in the corpora cavernosa penis: their long diameters, for the most part, corresponding with that of the penis.


The external envelope or outer coat of the corpus cavernosum urethrae is formed partly of unstriped muscular fibers, and a layer of the same tissue immediately surrounds the canal of the  urethra .


Trigonitis  is a condition of  inflammation  of the  trigone region  of the  bladder . It is more common in women. [ 1 ]


The cause of trigonitis is not known, and there is no solid treatment.   Electrocautery  is sometimes used, but is generally unreliable as a treatment, and typically does not have quick results.  Several drugs, such as  muscle relaxants ,  antibiotics ,  antiseptics  such as  Urised , have varied and unreliable results. Other forms of treatment include  urethrotomy ,  cryosurgery , and  neurostimulation . [ citation needed ]


The  tunica albuginea  is a layer of condensed  fibrous tissue  on the surface of the  ovary .


The tunica albuginea is composed of short  connective tissue  fibers. It is located immediately inside the surface  epithelium  (previously known as  germinal epithelium ) which is continuous with the  peritoneum . It is  non-vascularised . [ 1 ]  It is thinner than the  tunica albuginea of the testis , and its thickness varies across the  ovary . [ 1 ]


The tunica albuginea is formed late in  prenatal development . [ 1 ]  It buds off from mesonephric stroma. [ 1 ]


The  tunica albuginea  is a dense, [ 1 ] [ 2 ]  blue-white [ 3 ]  layer of  fibrous tissue  surrounding the  testis . [ 1 ] [ 4 ]  It is the middle of three envelopes forming the capsule of the testis; it is deep to the visceral layer of  tunica vaginalis , and superficial to the  tunica vasculosa testis (vascular layer of testis) . [ 5 ]


The connective tissue of the tunica albuginea testis extends into the substance of the testis to form fibrous partitions - the  septa testis . [ 1 ]  At the posterior aspect of the testis (where the serosa of testis is deficient to allow for the attachment of the  epididymis ), the tunica albuginea extends into the testis to form the  mediastinum testis . [ 5 ]


It is thicker than the  tunica albuginea of the ovary . [ 6 ]


It is composed of bundles of white fibrous  connective tissue  (from which it derives its name  albuginea ) which interlace in every direction. [ 7 ]


The  tunica vasculosa testis  ( vascular layer of testis ) is the inner-most of the three layers that form the capsule of the  testis . It consists of a vascular plexus and  loose connective tissue . It extends into the testis itself to line the surfaces of individual  septa of testis . [ 1 ]


Related to the  urinary bladder , anteriorly there are the following folds:


This article incorporates text in the  public domain  from  page 1231  of the 20th edition of   Gray's Anatomy   (1918)


Umbilical-urachal sinus   is a  congenital disorder  of the  urinary bladder  caused by failure of obliteration of proximal or distal part of the  allantois , and the presentation of this anomaly is more common in children and rarer in adults. [ 1 ] [ 2 ] [ 3 ]  In contrast to a  urachal diverticulum  (patent urachus), it is characterised by focal dilatation of the umbilical portion of the remnant urachal tract.


It is thought have been first described by Cabriolus in 1550. [ 4 ]


A  urachal diverticulum  (also  vesicourachal diverticulum ) is a  congenital disorder  caused by the partial persistence of the  allantois . The allantois, which later becomes the  urachus , connects an embryo's  bladder  to the  yolk sac . Normally, the urachus closes off to become the  median umbilical ligament ; however, if it does not seal close to the bladder, a blind pouch connected to the bladder remains. This is usually asymptomatic but can lead to recurrent  urinary tract infections . If the urachus is wholly patent,  urine  can drain from the bladder to an opening by the  umbilicus , a condition known as  urachal fistula . [ 1 ]


A  urachal fistula  is a  congenital disorder  caused by the persistence of the  allantois  (later,  urachus ), the structure that connects an embryo's  bladder  to the  yolk sac . Normally, the urachus closes off to become the  median umbilical ligament ; however, if it remains open,  urine  can drain from the bladder to an opening by the  umbilicus . [ 1 ]


This condition is a rare defect, mostly found in children, and is also known as an open or  patent urachus . [ 2 ] [ 3 ]


A  ureteral neoplasm  is a type of  tumor  that can be primary, or associated with a  metastasis  from another site. [ 1 ]


Treatment may involve removal of the  kidney  and  ureter , or just the ureter. [ 2 ]


Classification of cancers often is oriented around the embryological origin of the tissue. In some contexts, the primary division is at the border of kidney and ureter, and in other contexts, the primary division is between derivatives of the  metanephric blastema  and those of the  ureteric bud . Because of this, neoplasia of the ureters are sometimes grouped with tumors of the  renal pelvis . [ 3 ] [ 4 ]


This article about a  neoplasm  is a  stub . You can help Wikipedia by  expanding it .


The  ureteric plexus  is a  nerve plexus  covering and innervating the  ureter . The plexus can be graduated into three parts, as the ureter itself can be divided: In the upper part of the ureter, the plexus gets its  nerve fibers  mainly from the  renal plexus , but also from the  abdominal aortic plexus . In the intermediate part the plexus receives nervous input from the  superior hypogastric plexus  and in the lower part from the  inferior hypogastric plexus .


The plexus contains both  sympathetic  and  parasympathetic  fibers, where the sympathetic components come from T11 to L2 levels of the  spinal cord . Preganglionic   vagal  fibers (vagal fibers before passing through a ganglion) run through the  celiac plexus  and reach the ureteric plexus.


Ureteritis  is a medical condition of the  ureter  that involves  inflammation . [ 1 ] [ 2 ]  One form is known as "ureteritis cystica". [ 3 ]


Eosinophilic  ureteritis has been observed. [ 4 ]


Ureteritis is often considered part of a  urinary tract infection . [ citation needed ]


The  urethral crest  is an anatomical feature present in the  urinary system  of both males and females.


In males, the urethral crest is known as the  crista urethralis masculinae , or the  crista phallica , and is a longitudinal fold on the posterior wall of the  urethra  extending from the  uvula of the bladder  through the  prostatic urethra . [ 1 ]
It is from 15 to 17 mm. in length, and about 3 mm. in height, and contains muscular and erectile tissue.
When distended, it may serve to prevent the passage of the  semen  backward into the  bladder . [ 2 ]


In females, it is known as the  crista urethralis femininae , and is a conspicuous longitudinal fold of  mucosa  on the posterior wall of the urethra. [ 3 ]


Doctors have documented numerous cases of  insertion of  foreign bodies  into the  urethra , typically as the result of  auto-erotic  activities. This can result in infections and serious internal bleeding. [ 1 ] [ 2 ]


A wide variety of solid objects have been reported to have been inserted into the urethra, including batteries, safety pins, straws, [ 2 ]  and telephone wires. [ 3 ]  Liquefied objects have also been inserted into the urethra, such as an  injection of cocaine [ 4 ]  (which, arguably, had harmful results [ 5 ] [ clarification needed ] ).


The  Chuck Palahniuk  story "Guts", from the novel  Haunted , includes the story of a boy in his early teens inserting candle wax into his urethra. [ 6 ]


This  sexuality -related article is a  stub . You can help Wikipedia by  expanding it .


The  urethral or periurethral glands  (also  Littré glands  after  Alexis Littré ) [ 1 ]  are  glands  that branch off the wall of the  urethra  of mammals. The glands secrete  mucus [ 2 ]  and are most numerous in the section of the urethra that runs through the  penis . Urethral glands produce a  colloid  secretion containing  glycosaminoglycans ; this secretion protects the  epithelium  against  urine . [ 3 ]


Untreated  urethritis  can lead to infection of the urethral glands, which can in turn result in impeding  urethral strictures .


List of distinct cell types in the adult human body


A urethrovaginal fistula  is an abnormal passageway that may occur the urethra and the vagina. [ 1 ]  It is a sub-set of vaginal fistulas. [ 2 ] [ 3 ]  It results in urinary incontinence as urine continually leaves the vagina. It can occur as an  obstetrical complication ,  catheter  insertion injury or a  surgical injury . [ 4 ] [ 5 ]


It is also called a urethral fistula and may be referred to as UVF. [ 3 ] [ 6 ]  They are quite rare. In the developed world, they are typically due to injuries due to medical activity. [ 7 ]


Urine sodium  is a measurement of the concentration of  sodium  in the  urine .


It is a test ordered to distinguish between forms of renal failure and to classify the severity of hyponatremia. [ 1 ]


The urine sodium is expressed as a concentration (such as millimoles per liter).  The result must therefore be interpreted in the context of the degree of urine concentration present.  Alternatively, the urine sodium can be standardized to the excretion of  creatinine  using a formula such as the  fractional excretion of sodium (FENa) .


Because the  hypothalamus / osmoreceptor  system ordinarily works well to cause drinking or urination to restore the body's sodium concentrations to normal, this system can be used in medical treatment to regulate the body's total fluid content, by first controlling the body's sodium content. Thus, when a powerful  diuretic  drug is given which causes the kidneys to excrete sodium, the effect is accompanied by an excretion of body water (water loss accompanies sodium loss). This happens because the kidney is unable to efficiently retain water while excreting large amounts of sodium. In addition, after sodium excretion, the  osmoreceptor  system may sense lowered sodium concentration in the blood and then direct compensatory urinary water loss in order to correct the  hyponatremic  (low blood sodium) state.


Classifying renal disease


When classifying renal disease, urine sodium levels can provide insight into the underlying cause. [ 2 ]  A low urine sodium (<20 mEq/L) indicates an  acute kidney injury  (AKI), while sodium concentrations present high (>40 mEq/L) in  acute tubular necrosis . [ 2 ]


This  medical  diagnostic article is a  stub . You can help Wikipedia by  expanding it .


A  urogenital neoplasm  is a tumor of the  urogenital  system. [ 1 ]


Types include:


A urothelial papilloma is a rare, noncancerous tumor found within the urinary tract.


The most common presenting symptom is hematuria (blood in urine). The average age at which it occurs is 46 years old.


The tumor is made of a fibrovascular core covered by seemingly normal urothelium tissue. Under microscope, papillary (finger-like) fronds can be seen that feature occasional branching, but no fusion.


The tumors are diploid (contain two sets of chromosomes). They commonly show FGFR3 mutations. [ 1 ]


The  uterine cavity  is the inside of the  uterus . It is triangular in shape, the base (broadest part) being formed by the internal surface of the  body of the uterus  between the openings of the  fallopian tubes , the apex by the  internal orifice of the uterus  through which the cavity of the body communicates with the  canal of the cervix . The uterine cavity where it enters the openings of the fallopian tubes is a mere slit, flattened antero-posteriorly.


This article incorporates text in the  public domain  from  page 1260  of the 20th edition of   Gray's Anatomy   (1918)


The  uterine horns  ( cornua of uterus ) are the points in the upper  uterus  where the  fallopian tubes  or  oviducts  exit to meet the  ovaries . They are one of the points of attachment for the  round ligament of uterus  (the other being the  mons pubis ). They also provide attachment to the  ovarian ligament , which is located below the fallopian tube at the back, while the round ligament of uterus is located below the tube at the front.


The uterine horns are far more prominent in other animals (such as cows [ 1 ]  and cats [ 2 ] ) than they are in  humans . In the cat, implantation of the embryo occurs in one of the two uterine horns, not the body of the uterus itself.


Occasionally, if a fallopian tube does not connect, the uterine horn will fill with blood each month, and a minor one-day surgery will be performed to remove it.  Often, people who are born with this have trouble getting  pregnant  as both  ovaries  are functional and either may ovulate.  The spare  egg , that cannot travel the fallopian tube, is absorbed into the body.


Uterine hyperplasia , or  enlarged uterus , is a  medical symptom  in which the volume and size of the  uterus  in a female is abnormally high. It can be a symptom of  medical conditions  such as  adenomyosis ,  uterine fibroids ,  ovarian cysts , and  endometrial cancer . [ 1 ]


Uterine hypoplasia , also known as  naive uterus  or  infantile uterus , is a  reproductive disorder  characterized by  hypoplasia  of the  uterus . It is usually due to  pubertal failure / hypogonadism  and may be treated with  puberty induction  using  estrogens  and/or  progestogens .


The  uterine isthmus  is the inferior-posterior part of  uterus , on its  cervical  end — here, the uterine muscle ( myometrium ) is narrower and thinner. It connects the  body  and cervix. [ 1 ]


The uterine isthmus can become more compressibile in pregnancy, which is a finding known as  Hegar's sign .


The  fornices of the vagina  ( sg. :  fornix of the vagina  or  fornix vaginae ) are the  superior  portions of the  vagina , extending into the recesses created by the  vaginal portion of cervix . There is an anterior fornix and a posterior fornix. The word  fornix  is Latin for ' arch '.


During  sexual intercourse  in the  missionary position , the tip of the  penis  may reach the anterior fornix, while in the  rear-entry position  it may reach the posterior fornix. [ 1 ]


The anterior fornix is also called the  a-spot , an analogue to the  g-spot  (Gräfenberg spot), which is closer to the vaginal opening, and also on the anterior side of the vagina. [ 2 ]


This article incorporates text in the  public domain  from  page 1264  of the 20th edition of   Gray's Anatomy   (1918)


The  vaginal vault  is the expanded region of the vaginal canal at the internal end of the  vagina . [ 1 ]


The vaginal vault may  prolapse  after a  hysterectomy , as there is no uterus supporting the interior end of the vagina.


Colposacropexy  is often used for treating vaginal vault prolapse. A  Cochrane Collaboration  review [ needs update ]  found that limited data are available on optimal surgical approaches, including the use of  transvaginal surgical mesh  devices, in the form of a patch or  sling , similar to its implementation for abdominal  hernia . However, the use of a transvaginal mesh in treating vaginal prolapses is associated with side effects including  pain ,  infection , and  organ perforation . According to the  FDA , serious complications are "not rare." A number of  class action   lawsuits  have been filed and settled against several manufacturers of TVM devices.


Vasitis nodosa  is a  complication  experienced in approximately 66% of men who undergo  vasectomy . [ 1 ]  It is a  benign   nodular  thickening of the  vas deferens , in which small offshoots proliferate, infiltrating surrounding tissue. [ 2 ]   It can be mistaken for low-grade  adenocarcinoma  by  pathologists , [ 3 ]  and is implicated in late vasectomy failure. [ 2 ]


Vesicular appendages of the  epoöphoron  are small pedunculated vesicles of the  fimbriae  of the  uterine tube , or connected to the  broad ligament .  They were described by  Giovanni Battista Morgagni  and are remnants of the cranial part of the  mesonephric duct . Typically they are asymptomatic.


In the male, remnants of the paramesonephric duct may be present as well and are also known as  appendix of testis  or  hydatid of Morgagni .


They are rarely absent, and are attached either to the free margin of the mesosalpinx or
to one of the fimbriae, and are pedunculated vesicles, filled with fluid, about the size of a small pea.
The pedicles frequently attain a considerable length. [ 1 ]


Vestibular adenitis  is a condition affecting the  vagina . [ 1 ]  It is a chronic  inflammation  of the lesser  vestibular glands , which lie just outside the  hymenal ring . The condition can lead to small, extremely painful  ulcerations  of the  vestibular mucosa . [ 2 ]


Myiasis  is a parasitic infestation caused by larvae of several fly species. Diagnosis and treatment are generally quite simple. This infestation is, however, rarely seen in the  vulvar  area. Infestation of vulvar area with larvae and maggots is called  vulvar myiasis . Very few cases have been described in literature. [ 1 ]


Activin  and  inhibin  are two closely related  protein   complexes  that have almost directly opposite biological effects. Identified in 1986, [ 1 ] [ 2 ]  activin enhances  FSH   biosynthesis  and  secretion , and participates in the regulation of the  menstrual cycle . Many other functions have been found to be exerted by activin, including roles in cell proliferation,  differentiation ,  apoptosis , [ 3 ]   metabolism ,  homeostasis ,  immune response ,  wound repair , [ 4 ]  and  endocrine  function. Conversely, inhibin downregulates FSH synthesis and inhibits FSH secretion. [ 5 ]  The existence of inhibin was hypothesized as early as 1916; however, it was not demonstrated to exist until  Neena Schwartz  and  Cornelia Channing 's work in the mid-1970s, after which both proteins were molecularly characterized ten years later. [ 6 ]


Activin is a  dimer  composed of two identical or very similar beta subunits. Inhibin is also a dimer wherein the first component is a beta subunit similar or identical to the beta subunit in activin. However, in contrast to activin, the second component of the inhibin dimer is a more distantly-related alpha subunit. [ 7 ] [ 8 ]  Activin, inhibin and a number of other structurally related proteins such as  anti-Müllerian hormone ,  bone morphogenetic protein , and  growth differentiation factor  belong to the  TGF-β protein superfamily . [ 9 ]


The activin and inhibin protein complexes are both dimeric in structure, and, in each complex, the two monomers are linked to one another by a single  disulfide bond . [ 10 ]  In addition, both complexes are derived from the same family of related genes and proteins but differ in their subunit composition. [ 7 ]  Below is a list of the most common inhibin and activin complexes and their subunit composition:


The alpha and beta subunits share approximately 25%  sequence similarity , whereas the similarity between beta subunits is approximately 65%. [ 9 ]


In mammals, four beta subunits have been described, called activin β A , activin β B , activin β C  and activin β E . Activin β A  and β B  are identical to the two beta subunits of inhibin. A fifth subunit, activin β D , has been described in  Xenopus laevis . Two activin β A  subunits give rise to activin A, one β A , and one β B  subunit gives rise to activin AB, and so on. Various, but not all theoretically possible, heterodimers have been described. [ 11 ] [ 12 ]  The subunits are linked by a single covalent disulfide bond.


The  β C  subunit is able to form activin heterodimers with β A  or β B  subunits but is unable to dimerize with inhibin α. [ 13 ]


Activin is produced in the  gonads ,  pituitary gland ,  placenta , and other organs:


In both females and males, inhibin inhibits  FSH  production. Inhibin does not inhibit the secretion of GnRH from the hypothalamus. [ 16 ] [ 17 ]  However, the overall mechanism differs between the sexes:


Inhibin is produced in the  gonads ,  pituitary gland ,  placenta ,  corpus luteum  and other organs.


FSH stimulates the secretion of inhibin from the  granulosa cells  of the ovarian follicles in the  ovaries . In turn, inhibin suppresses FSH.


Inhibin secretion is diminished by  GnRH , and enhanced by  insulin-like growth factor -1 (IGF-1).


It is secreted from the  Sertoli cells , [ 18 ]  located in the  seminiferous tubules  inside the  testes .  Androgens  stimulate inhibin production; this  protein  may also help to locally regulate  spermatogenesis . [ 19 ]


As with other members of the superfamily, activins interact with two types of cell surface  transmembrane receptors  (Types I and II) which have intrinsic  serine/threonine kinase  activities in their cytoplasmic domains:


Activin binds to the Type II receptor and initiates a cascade reaction that leads to the recruitment, phosphorylation, and activation of Type I activin receptor. This then interacts with and then phosphorylates  SMAD2  and  SMAD3 , two of the cytoplasmic  SMAD  proteins.


Smad3 then translocates to the nucleus and interacts with  SMAD4  through multimerization, resulting in their modulation as  transcription factor  complexes responsible for the expression of a large variety of genes.


In contrast to activin, much less is known about the mechanism of action of inhibin, but may involve competing with activin for binding to activin receptors and/or binding to inhibin-specific receptors. [ 8 ]


Activin A is more plentiful in the  adipose tissue  of obese, compared to lean persons. [ 20 ]  Activin A promotes the proliferation of  adipocyte   progenitor cells , while inhibiting their  differentiation  into adipocytes. [ 20 ]  Activin A also increases inflammatory  cytokines  in  macrophages . [ 20 ]


A  mutation  in the gene for the activin receptor  ACVR1  results in  fibrodysplasia ossificans progressiva , a fatal disease that causes muscle and soft tissue to gradually be replaced by bone tissue. [ 21 ]  This condition is characterized by the formation of an extra skeleton that produces immobilization and eventually death by suffocation. [ 21 ]  The mutation in ACVR1 causes activin A, which normally acts as an antagonist of the receptor and blocks  osteogenesis  (bone growth), to behave as an agonist of the receptor and to induce hyperactive bone growth. [ 21 ]  On 2 September 2015,  Regeneron Pharmaceuticals  announced that they had developed an  antibody  for  activin A  that effectively cures the disease in an  animal model  of the condition. [ 22 ]


Mutations in the ACVR1 gene have also been linked to cancer, especially  diffuse intrinsic pontine glioma (DIPG). [ 23 ] [ 24 ] [ 25 ]


Elevated Activin B levels with normal Activin A levels provided a possible  biomarker  for  myalgic encephalomyelitis/chronic fatigue syndrome . [ 26 ]


Activin A is overexpressed in many  cancers . It was shown to promote  tumorigenesis  by hampering the  adaptive   anti-tumor immune response  in  melanoma . [ 27 ]


Quantification of inhibin A is part of the prenatal  quad screen  that can be administered during pregnancy at a gestational age of 16–18 weeks. An elevated inhibin A (along with an increased  beta-hCG , decreased  AFP , and a decreased  estriol ) is suggestive of the presence of a fetus with  Down syndrome . [ 28 ]  As a screening test, abnormal quad screen test results need to be followed up with more definitive tests.


It also has been used as a marker for  ovarian cancer . [ 29 ] [ 30 ]


Inhibin B may be used as a marker of  spermatogenesis  function and  male infertility . The mean serum inhibin B level is significantly higher among fertile men (approximately 140 pg/mL) than in infertile men (approximately 80 pg/mL). [ 31 ]  In men with  azoospermia , a positive test for inhibin B slightly raises the chances for successfully achieving pregnancy through  testicular sperm extraction  (TESE), although the association is not very substantial, having a sensitivity of 0.65 (95% confidence interval [CI]: 0.56–0.74) and a specificity of 0.83 (CI: 0.64–0.93) for prediction the presence of sperm in the testes in non-obstructive azoospermia. [ 32 ]


An  androgen-dependent condition ,  disease ,  disorder , or  syndrome , is a  medical condition  that is, in part or full, dependent on, or is sensitive to, the presence of  androgenic  activity in the body. [ citation needed ]


Known androgen-dependent conditions include  acne , [ 1 ]   seborrhea , [ 2 ] [ 3 ] [ 4 ]   androgenic alopecia , [ 5 ]   hirsutism , [ 6 ]   hidradenitis suppurativa , [ 7 ]   precocious puberty  in boys, [ 8 ]   hypersexuality , [ 9 ]   paraphilias , [ 10 ]   benign prostatic hyperplasia  (BPH), [ 11 ]   prostate cancer , [ 12 ]  and  hyperandrogenism  in women such as in  polycystic ovary syndrome  (PCOS),  congenital adrenal hyperplasia  (CAH), and androgen-secreting  tumors  ( gonadal  or  adrenal tumor ). [ 13 ] [ 14 ]


Such conditions may be treated with  drugs  with  antiandrogen  actions, including  androgen receptor   antagonists  such as  cyproterone acetate ,  spironolactone , and  bicalutamide ,  5α-reductase inhibitors  such as  finasteride  and  dutasteride ,  CYP17A1  inhibitors such as  abiraterone acetate ,  gonadotropin-releasing hormone  (GnRH)  analogues  such as  leuprorelin  and  cetrorelix , and/or other  antigonadotropins  such as  megestrol acetate  and  medroxyprogesterone acetate . [ 15 ] [ 16 ]


This article about an endocrine, nutritional, or metabolic disease is a  stub . You can help Wikipedia by  expanding it .


Capacitation  is the penultimate [ 1 ]  step in the maturation of  mammalian   spermatozoa  and is required to render them competent to  fertilize  an  oocyte . [ 2 ]  This step is a biochemical event; the sperm move normally and look mature prior to capacitation.
 In vivo , capacitation occurs after  ejaculation , when the spermatozoa leave the vagina and enter the upper  female reproductive tract . The  uterus  aids in the steps of capacitation by secreting sterol-binding  albumin ,  lipoproteins , and  proteolytic  and  glycosidasic   enzymes  such as heparin.


For purposes of  in vitro  fertilization, capacitation occurs by incubating spermatozoa that have either undergone ejaculation or have been extracted from the  epididymis  and incubated in a defined medium for several hours. There are different techniques to perform the capacitation step: simple washing, migration (swim-up), density gradients, and filter. The objective is to isolate as many motile spermatozoa as possible and to eliminate non-motile or dead spermatozoa. After either  in vivo  or  in vitro  capacitation the sperm must undergo the final maturation step, activation, involving the  acrosome reaction .


Non-mammalian spermatozoa do not require this capacitation step and are ready to fertilize an oocyte immediately after release from the male.


Capacitation has two effects: destabilisation of the acrosomal sperm head membrane which allows it to penetrate the outer layer of the egg, and chemical changes in the tail that allow a greater mobility in the sperm. [ 3 ]  The changes are facilitated by the removal of  sterols  (e.g.  cholesterol ) and non-covalently bound epididymal/seminal  glycoproteins . The result is a more fluid membrane with an increased permeability to Ca 2+  ion.


An influx of Ca 2+  produces increased intracellular  cAMP  levels and thus, an increase in motility.  Hyperactivation  coincides with the onset of capacitation and is the result of the increased Ca 2+  levels. It has a synergistic stimulatory effect with adenosine that increases  adenylyl cyclase  activity in the sperm. [ citation needed ]


The tripeptide  fertilization promoting peptide  (FPP) is essential for controlling capacitation. FPP is produced in the  prostate gland  as a component of the seminal fluid. FPP comes into contact with the spermatozoa during ejaculation, as the sperm and seminal fluid mix. High levels of active FPP prevent capacitation. After ejaculation, the concentration of FPP drops in the female reproductive tract.  [ citation needed ]


Because  assisted reproductive technologies , or ARTs, such as  in vitro  fertilization  (IVF) or  intrauterine insemination  (IUI) require the induction of sperm cell capacitation outside of normal biological parameters, numerous methods have been developed to induce this process in mammalian sperm cells. Sperm cells are harvested through ejaculation or harvested from the caudal  epididymis  and allowed to liquefy at room temperature. Capacitation can then be induced by adding media designed to mimic the electrolytic composition of the  fallopian tubes , where fertilization occurs. These media vary between species, but are saline-based and contain energy substrates such as lactate, pyruvate, and possibly glucose. A cholesterol acceptor is required to facilitate the removal of cholesterol from the sperm cell membrane, which is always albumin.  Bovine serum albumin  is typically used for  in vitro  animal studies, and  human serum albumin  (HSA) is used in human sperm capacitation induction.


Bicarbonate  is a vital component of capacitation-inducing media, as it is co-transported into the  cytosol  where it activates soluble  adenylyl cyclase  (sAC) as well as acts as a pH buffer necessary to prevent decreasing the pH in the culture, a necessary addition when incubating cells at 5% CO 2  as is generally used although not required.  Calcium chloride  is added to facilitated the influx via of calcium cations. [ 4 ] [ 5 ]  In animal models, Tyrode's albumin lactate pyruvate (TALP) medium is typically used as a base, which contains each of these components. In humans, human tubal fluid (HTF) is used.


These media can be supplemented with other chemicals to induce hyperactivated sperm motility and/or the acrosome reaction. For animal in vitro fertilization,  caffeine  at 5 mM concentration is a strong inducer of sperm capacitation  in vitro . [ 6 ] [ 7 ]  Calcium  ionophores  are also ideal to induce capacitation. [ 7 ]  Adding heparin to capacitation inducing medium mimics the secretion of heparin-like  gycosaminoglycans  (GAGs) near the oocyte and initiates the acrosome reaction. This effect is magnified when adding  lysophosphatidylcholine  (LC) in conjunction with heparin. [ 8 ]   Catecholamines  such as  norepinephrine  at low concentrations have been shown to assist in acrosome reaction induction. [ 9 ]


The traditional methods to perform  in vitro  capacitation are:


However, nowadays there are new techniques which surpass these ones. For instance, we have PICSI, MACS or microfluidic chips.


Numerous methods have been developed to assess the degree to which sperm cells are undergoing capacitation in vitro. Computer-aided sperm analysis (CASA) was developed in the 1980s for measuring sperm kinematics. [ 11 ]  CASA uses  phase-contrast microscopy  combined with sperm tracking software to analyze sperm motility parameters. [ 11 ]  Certain parameters such as curvilinear velocity (VCL), straightline velocity (VSL), average path velocity (VAP), and the amplitude of lateral head displacement (ALH) have been shown to be positively correlated with the acquisition of fertilization competency and are thus used to identify hyperactive sperm cell motility. [ 12 ]


While motility measurements are critical for identifying the presence of hyperactive motility, additional methods have been developed to identify the occurrence of the acrosome reaction. A simple method uses Coomassie brilliant blue G250 to stain cells, providing visual evidence of intact or reacted acrosomes. [ 13 ]  More advanced techniques employ fluorescent or  electron microscopy  methods.  Fluorescein -conjugated  Peanut agglutinin  (FITC-PNA) or  Pisum sativum   agglutinin  (FITC-PSA) can be used to fluorescently tag the acrosome of sperm cells, which can be then used to assess the status of the acrosome using a  fluorescent microscope . [ 14 ] [ 15 ] [ 16 ]


The discovery of this process was independently reported in 1951 by both  Min Chueh Chang [ 17 ]  and  Colin Russell Austin . [ 18 ] [ 19 ]


The  dartos fascia ,  dartos tunic  or simply  dartos  is a layer of  connective tissue  found in the  penile shaft ,  foreskin  and  scrotum . [ 1 ]  The penile portion is referred to as the  superficial fascia of penis  or the  subcutaneous tissue of penis , [ 2 ]  while the scrotal part is the dartos proper. In addition to being continuous with itself between the scrotum and the penis, it is also continuous with  Colles' fascia  of the perineum and  Scarpa's fascia  of the abdomen. [ 1 ]


The dartos lies just below the skin, which places it just superficial to the external spermatic fascia in the scrotum and to  Buck's fascia  in the penile shaft. In the scrotum, it consists mostly of  smooth muscle . [ 3 ]  The tone of this smooth muscle is responsible for the wrinkled (rugose) appearance of the scrotum. [ 1 ]  In females, the same muscle fibers are less well developed and termed  dartos muliebris , lying beneath the skin of the  labia majora . The dartos fascia receives innervation from  postganglionic sympathetic nerve fibers  arriving via the  ilioinguinal nerve  and the  posterior scrotal nerve .


In the penis, the loose attachment of the dartos fascia to Buck's fascia is responsible for the high degree of mobility of the penile skin over the underlying tissue. [ 1 ]  It is also responsible for carrying the blood supply of the penile skin, a longitudinally-coursing anastomotic network of vessels that arise from the external pudendal vessels. [ 1 ]


In the scrotum, the dartos fascia acts to regulate the  temperature  of the  testicles , which promotes  spermatogenesis . It does this by expanding or contracting to wrinkle the scrotal skin.


The dartos muscle works in conjunction with the  cremaster muscle  to elevate the  testis  but should not be confused with the  cremasteric reflex .


The dartos fascia keeps the foreskin close to the glans penis throughout life. In infancy, the dartos fascia operates as a one-way check valve at the tip of the foreskin, allowing urine to pass out, but prohibiting the entry of foreign matter and pathogens.


There is an increase in elastic fibers with increasing maturity that allows the foreskin to become retractable by adulthood and glide freely back and forth.


Etymology:


Some dartos-related terms:


An  estrogen-dependent condition  can be that relating to the differentiation in the steroid sex hormone that is associated with the female reproductive system and sex characteristics. [ 1 ]  These conditions can fall under the umbrella of hypoestrogenism, hyperestrogenim, or any sensitivity to the presence of estrogen in the body.


Estrogen  is a critical sex hormone for women (in conjunction with  progesterone ). Estrogen is responsible for all different functions in a female body, but is also seen in any gender. [ 1 ]  These functions are seen in body tracts such as the skeletal system, liver, brain and breasts. [ 2 ]  There are three different formulations of estrogen:  estrone ,  estradiol , and  estriol . [ 1 ]  These are commonly referred to as E1, E2, and E3, following the listing stated prior. These three formulations have different functions in a women's life. Estradiol (E2) is seen in the reproductive time period. [ 1 ]  Estriol (E3) is seen primarily during pregnancy. [ 1 ]  Finally, estrone (E1) is the form the body uses during the postmenopausal period. [ 1 ]  From all of the three formulations stated earlier, Estradiol (E2) is known to be the strongest. [ 1 ]  In a normal adult female, the normal range of estrogen in the luteal phase (when ovulation happens, as well as the vascular tissue preparing for the potential zygote  [ 3 ] ) is 100 pg/ml, in comparison to the proliferative phase (when the uterine lining is thickening [ 4 ] ) 40-250 pg/ml. [ 5 ]


Known estrogen-dependent conditions include:


Such conditions may be treated with  drugs  with  antiestrogen  actions, including  selective estrogen receptor modulators  (SERMs) such as  tamoxifen  and  clomifene ,  estrogen receptor   antagonists  such as  fulvestrant ,  aromatase inhibitors  such as  anastrozole  and  exemestane , [ 12 ]   gonadotropin-releasing hormone  (GnRH)  analogues  such as  leuprorelin  and  cetrorelix , and/or other  antigonadotropins  such as  danazol ,  gestrinone ,  megestrol acetate , and  medroxyprogesterone acetate . [ 21 ] [ 22 ]


Menopause is the state in which the menses ceasen to occur. This is seen throughout the years 49–52. [ 23 ]  This termination of menses is associated with a dramatic drop in estrogen levels. The estrogen levels stated previously dramatically decrease to approximately 20 pg/ml [ 5 ]  or less when menopause begins. Menopause falls under the umbrella of conditions related to hypoestrogenism. There are many symptoms associated with the transition and entrance into menopause.


Endometriosis is an inflammatory condition characterized by the growth and development on the endometrium tissue, found within the uterus, is growing outside of the uterus. [ 24 ] [ 25 ]  Endometriosis is commonly found on the ovaries and other organs near/in the pelvic cavity, but it has also been seen in other organs such as the spleen or lungs. [ citation needed ]  A handful of the symptoms associated with endometriosis are dysmenorrhea, dyschezia, dyspareunia, menorrhagia, and fertility complications. [ 26 ]  This inflammatory disease shares numerous symptoms with other conditions, so this at times leads to misdiagnoses. Endometriosis can have a confirmed diagnosis with exploratory surgery. This surgery is generally called a laparoscopy. [ 27 ]


Polycystic ovarian syndrome (PCOS) is seen as numerous cysts developing on the ovaries, and this can be seen with additional symptoms such as oligomenorrhea, hirsutism, acne, weight gain, and fertility issues. [ 28 ] [ 29 ]  PCOS is caused by the ovaries having an excessive amount of male sex hormones. Because of this, PCOS is associated with hyperandrogegism. [ 29 ]


The  genital papilla  is an anatomical feature of the external  genitalia  of some animals.


In mammals, the genital papilla is a part of the  vulva  not present in humans, which appears as a small, fleshy flab of tissue. The papilla covers the opening of the  vagina . [ 1 ]


The genital papilla (urogenital/genital pore) is a small, fleshy tube behind the anus present in most  teleost  fish, from which the sperm or eggs are released; [ 2 ]  the sex of a fish often can be determined by the shape of its papilla.


This fish-related article is a  stub . You can help Wikipedia by  expanding it .


This article about a  mammal  is a  stub . You can help Wikipedia by  expanding it .


The  hydatid of Morgagni  can refer to one of two closely related bodily structures:


Hypogonadism  means diminished functional activity of the  gonads —the  testicles  or the  ovaries —that may result in diminished  production of   sex hormones . Low  androgen  (e.g.,  testosterone ) levels are referred to as  hypoandrogenism  and low  estrogen  (e.g.,  estradiol ) as  hypoestrogenism . These are responsible for the observed signs and symptoms in both males and females.


Hypogonadism, commonly referred to by the symptom " low testosterone " or " Low T ", can also decrease other hormones secreted by the gonads including  progesterone ,  DHEA ,  anti-Müllerian hormone ,  activin , and  inhibin .  Sperm development  (spermatogenesis) and  release of the egg from the ovaries  (ovulation) may be impaired by hypogonadism, which, depending on the degree of severity, may result in partial or complete  infertility .


In January 2020, the  American College of Physicians  issued clinical guidelines for  testosterone  treatment in adult men with age-related low levels of testosterone. The guidelines are supported by the  American Academy of Family Physicians . The guidelines include patient discussions regarding testosterone treatment for  sexual dysfunction ; annual patient evaluation regarding possible notable improvement and, if none, to discontinue testosterone treatment; physicians should consider intramuscular treatments, rather than transdermal treatments, due to costs and since the effectiveness and harm of either method is similar; and, testosterone treatment for reasons other than possible improvement of sexual dysfunction may not be recommended. [ 1 ] [ 2 ]


Deficiency of sex hormones can result in defective primary or secondary sexual development, or withdrawal effects (e.g., premature  menopause ) in adults. Defective egg or sperm development results in  infertility . The term hypogonadism usually means permanent rather than transient or reversible defects, and usually implies deficiency of reproductive hormones, with or without  fertility  defects. The term is less commonly used for infertility without hormone deficiency. There are many possible types of hypogonadism and several ways to categorize them. Hypogonadism is also categorized by endocrinologists by the level of the reproductive system that is defective. Physicians measure  gonadotropins  ( LH  and  FSH ) to distinguish primary from secondary hypogonadism. In primary hypogonadism the LH and/or FSH are usually elevated, meaning the problem is in the testicles (hyper-gonatropic hypogonadism); whereas in secondary hypogonadism, both are normal or low, suggesting the problem is in the brain (hypo-gonatropic hypogonadism). [ citation needed ]


Hypogonadism can involve just  hormone  production or just  fertility , but most commonly involves both. [ citation needed ]


Hypogonadism can occur in other conditions, like  Prader–Willi syndrome . [ citation needed ]


Women with hypogonadism do not begin  menstruating  and it may affect their height and  breast development . Onset in women after  puberty  causes cessation of menstruation, lowered libido, loss of body hair, and  hot flashes . In men, it causes impaired muscle and body hair development,  gynecomastia , decreased height,  erectile dysfunction , and sexual difficulties. If hypogonadism is caused by a disorder of the  central nervous system  (e.g., a  brain tumor ), then this is known as  central hypogonadism . Signs and symptoms of central hypogonadism may involve headaches, impaired vision,  double vision ,  milky discharge from the breast , and symptoms caused by other hormone problems. [ 6 ]


The symptoms of  hypogonadotrophic hypogonadism , a subtype of hypogonadism, include late, incomplete or lack of development at puberty, and sometimes short stature or the inability to smell; in females, a lack of breasts and menstrual periods, and in males a lack of sexual development, e.g., facial hair, penis and testes enlargement, deepening voice. [ citation needed ]


Testing serum  LH  and  FSH  levels are often used to assess hypogonadism in women, particularly when  menopause  is believed to be happening. These levels change during a woman's normal menstrual cycle, so the history of having ceased menstruation coupled with high levels aids the diagnosis of being menopausal. Commonly, the post-menopausal woman is not called hypogonadal if she is of typical menopausal age. Contrast with a young woman or teen, who would have hypogonadism rather than menopause. This is because hypogonadism is an abnormality, whereas menopause is a normal change in hormone levels. In any case, the LH and FSH levels will rise in cases of primary hypogonadism or menopause, while they will be low in women with secondary or tertiary hypogonadism. [ 7 ]


Hypogonadism is often discovered during evaluation of  delayed puberty , but ordinary delay, which eventually results in normal  pubertal  development, wherein reproductive function is termed  constitutional delay . It may be discovered during an  infertility  evaluation in either men or women. [ 8 ]


Low  testosterone  can be identified through a simple blood test performed by a laboratory, ordered by a health care provider. Blood for the test must be taken in the morning hours, when levels are highest, as levels can drop by as much as 13% during the day and all normal reference ranges are based on morning levels. [ 9 ] [ 10 ]


Normal total testosterone levels depend on the man's age but generally range from 240 to 950 ng/dL (nanograms per deciliter) or 8.3–32.9 nmol/L (nanomoles per liter). [ 11 ]  According to American Urological Association, the diagnosis of low testosterone can be supported when the total testosterone level is below 300 ng/dl. [ 12 ]  Some men with normal total testosterone have low free or bioavailable testosterone levels which could still account for their symptoms. Men with low serum testosterone levels should have other hormones checked, particularly  luteinizing hormone  to help determine why their testosterone levels are low and help choose the most appropriate treatment (most notably, testosterone is usually not appropriate for secondary or tertiary forms of male hypogonadism, in which the LH levels are usually reduced). [ citation needed ]


Treatment is often prescribed for total testosterone levels below 230 ng/dL with symptoms. [ 13 ]  If the serum total testosterone level is between 230 and 350 ng/dL, free or bioavailable testosterone should be checked as they are frequently low when the total is marginal. [ citation needed ]


The standard range given is based on widely varying ages and, given that testosterone levels naturally decrease as humans age, age-group specific averages should be taken into consideration when discussing treatment between doctor and patient. [ 14 ]  In men, testosterone falls approximately 1 to 3 percent each year. [ 15 ]


A position statement by the Endocrine Society expressed dissatisfaction with most assays for total, free, and bioavailable testosterone. [ 16 ]  In particular, research has questioned the validity of commonly administered assays of free testosterone by radioimmunoassay. [ 16 ]  The free androgen index, essentially a calculation based on total testosterone and sex hormone-binding globulin levels, has been found to be the worst predictor of free testosterone levels and should not be used. [ 17 ]  Measurement by equilibrium dialysis or mass spectroscopy is generally required for accurate results, particularly for free testosterone which is normally present in very small concentrations. [ citation needed ]


Screening males who do not have symptoms for hypogonadism is not recommended as of 2018. [ 18 ]


Male primary or  hypergonadotropic hypogonadism  is often treated with  testosterone replacement therapy  if they are not trying to conceive. [ 13 ]


In short- and medium-term testosterone replacement therapy the risk of  cardiovascular events  (including  strokes  and  heart attacks  and other heart diseases)is not increased. The long-term safety of the therapy is not known yet. [ 19 ] [ 20 ]  Side effects can include an elevation of  hematocrit  to levels that require blood withdrawal ( phlebotomy ) to prevent complications from excessively thick blood.  Gynecomastia  (growth of breasts in men) sometimes occurs. Finally, some physicians worry that  obstructive sleep apnea  may worsen with testosterone therapy, and should be monitored. [ 21 ]


While historically, men with prostate cancer risk were warned against testosterone therapy, that has shown to be a myth. [ 22 ]


Another treatment for hypogonadism is  human chorionic gonadotropin  (hCG). [ 23 ]  This stimulates the LH receptor, thereby promoting testosterone synthesis. This will not be effective in men whose testes simply cannot synthesize testosterone anymore (primary hypogonadism), and the failure of hCG therapy is further support for the existence of true testicular failure in a patient. It is particularly indicated in men with hypogonadism who wish to retain their fertility, as it does not suppress  spermatogenesis  (sperm production) as testosterone replacement therapy does. [ citation needed ]


For both men and women, an alternative to testosterone replacement is low-dose  clomifene  treatment, which can stimulate the body to naturally increase hormone levels while avoiding infertility and other side effects that can result from direct hormone replacement therapy. [ 24 ]  Clomifene blocks estrogen from binding to some estrogen receptors in the  hypothalamus , thereby causing an increased release of  gonadotropin-releasing hormone  and subsequently LH from the pituitary. Clomifene is a  selective estrogen receptor modulator  (SERM). Generally, clomifene does not have adverse effects at the doses used for this purpose.


An  ovotestis  is a  gonad  with both  testicular  and  ovarian  aspects. [ 1 ] [ 2 ]  In humans, ovotestes are an infrequent anatomical variation associated with  gonadal dysgenesis . [ 3 ]  The only mammals where ovotestes are not symptomatic of a disorder are  moles , wherein females possess ovotestes along with a masculinized  clitoris . These ovotestes in nonpregnant female moles secrete eight times as much testosterone as the ovotestes of pregnant moles. [ 4 ]  In invertebrates that are normally  hermaphroditic , such as most  gastropods  (snails and slugs) in the clade  Eupulmonata , an ovotestis is a common feature of the reproductive anatomy.


In mice, ovotestes are structured such that the central region is testicular tissue while the poles both contain ovarian tissue. Experiments involving the  SOX9  gene, which is initiated by the  SRY  region of the Y chromosome, have shown the gene's requirement for testicular differentiation from the presence of ovotestis formation within XX Sox9 trangenic mice. (6)  Ovotestis within B6-XYPOS mice allow for gonadal development research within the same tissue to take place in ways previously unavailable. [ 5 ] [ 6 ]


An  ovotestis  or  hermaphroditic gland  ( Latin :  glandula hermaphroditica ), [ 7 ]  is found as normal anatomical feature in the  reproductive system of some gastropods  including such species as the land snail  Cornu aspersum . [ 8 ]


A  t-shaped uterus  is a type of  uterine malformation  wherein the uterus is shaped resembling the letter T. [ 1 ]  This is typically observed in  DES -exposed women. [ 2 ]  It is recognised in the  ESHRE/ESGE  classification, [ 3 ]  and is associated with failed  implantation , increased risk of  ectopic pregnancy ,  miscarriage  and preterm delivery. There is a surgical procedure to correct the malformation. [ 4 ]


The T-shaped malformation is commonly associated with in-utero exposure to diethylstilbestrol (the so-called " DES daughters ").  It is also presented  congenitally . [ 5 ]


Women are often diagnosed with this condition after several failed pregnancies, proceeded by exploratory diagnostic procedures, such as  magnetic resonance ,  sonography , and particularly  hysterosalpingography . [ 6 ] [ 7 ] [ 8 ]  In such studies, a widening of the  interstitial  and  isthmus of uterine tube  is observed, as well as constrictions or narrowing of the uterus as a whole, especially the lower and lateral portions, hence the "t" denomination. The uterus might be simultaneously reduced in volume, and other abnormalities might be concomitantly present. [ 9 ]


Although fertility is impaired, T-shaped uterus sufferers can bear children.  However, they carry a greater risk of complications, such as miscarriages, reduced fertility and preterm births, both before and after any treatment. [ 10 ] [ 11 ]


The current surgical procedure to treat this malformation, termed a  hysteroscopic  correction or  metroplasty , is undertaken by performing a lateral  incision  of the uterine walls, and can return the organ to a normal morphology, while improving the patient's former reproductive performance. [ 4 ] [ 10 ] [ 12 ]  It is considered a low-risk procedure, and can also improve  term delivery  rate by up to 10-fold, as long as the  endometrium  is considered to be in good condition. [ 13 ] [ 14 ] [ 15 ]  However, risks after the procedure include  placenta accreta ,  Asherman's syndrome  and severe  haemorrhage . [ 4 ] [ 16 ]


The  urethra  ( pl. :  urethras  or  urethrae ) is the tube that connects the  urinary bladder  to the  urinary meatus , [ 1 ] [ 2 ]  through which  placental mammals   urinate  and  ejaculate . [ 3 ]  In non-mammalian  vertebrates , the urethra also transports semen but is separate from the urinary tract. [ 4 ]


The external  urethral sphincter  is a  striated muscle  that allows voluntary control over urination. [ 5 ]  The  internal sphincter , formed by the involuntary  smooth muscles  lining the bladder neck and urethra, receives its nerve supply by the  sympathetic  division of the  autonomic nervous system . [ 6 ]  The internal sphincter is present both in males and females. [ 7 ] [ 8 ] [ 9 ]


The urethra is a fibrous and muscular tube which connects the  urinary bladder  to the  external urethral meatus . Its length differs between the sexes, because it passes through the  penis  in males.


In the human male, the urethra is on average 18 to 20 centimeters (7 to 8 inches) long and opens at the end of the external urethral meatus. [ 10 ]


The urethra is divided into four parts in men, named after the location: [ 10 ]


These openings are collectively called the verumontanum (colliculus seminalis).
The prostatic urethra is a common site of obstruction to outflow of urine in BPH patients


Stratified squamous  – distally


There is inadequate data for the typical length of the male urethra; however, a study of 109 men showed an average length of 22.3 cm (SD = 2.4 cm), ranging from 15 cm to 29 cm. [ 14 ]


The urethra in male placental mammals is typically longer than in females. [ 15 ]


In the human female, the urethra is about 4 cm long, [ 10 ] [ 12 ]  having 6 mm diameter, [ 12 ]  and exits the body between the  clitoris  and the  vaginal opening , extending from the  internal  to the  external urethral orifice . The meatus is located below the clitoris. It is placed behind the  symphysis pubis , embedded in the anterior wall of the vagina, and its direction is obliquely downward and forward; it is slightly curved with the concavity directed forward. The proximal two-thirds of the urethra is lined by  transitional epithelial cells , while the distal third is lined by  stratified squamous epithelial cells . [ 16 ]


Between the  superior  and  inferior fascia  of the  urogenital diaphragm , the female urethra is surrounded by the  urethral sphincter .


The urethra in female placental mammals is typically shorter than in the male. [ 15 ]


The cells lining the urethra (the  epithelium ) start off as  transitional cells  as it exits the bladder, which are variable layers of flat to cuboidal cells that change shape depending on whether they are compressed by the contents of the urethra. [ 17 ]  Further along the urethra there are  pseudostratified columnar  and  stratified columnar  epithelia. [ 17 ]  The lining becomes  multiple layers of flat cells  near the end of the urethra, which is the same as the external skin around it. [ 17 ]


There are small  mucus -secreting urethral glands, as well as bulbo-urethral glands of Cowper, that secrete mucous acting to lubricate the urethra. [ 17 ]


The urethra consists of three coats: muscular, erectile, and mucous, the muscular layer being a continuation of that of the bladder.


Somatic  (conscious) innervation of the  external urethral sphincter  is supplied by the  pudendal nerve .


In the developing  embryo , at the hind end lies a  cloaca . This, over the fourth to the seventh week, divides into a  urogenital sinus  and the beginnings of the  anal canal , with a wall forming between these two inpouchings called the  urorectal septum . [ 18 ]  The urogenital sinus divides into three parts, with the middle part forming the urethra; the upper part is largest and becomes the  urinary bladder , and the lower part then changes depending on the biological sex of the embryo. [ 18 ]  The cells lining the urethra (the epithelium) come from  endoderm , whereas the connective tissue and smooth  muscle  parts are derived from  mesoderm . [ 18 ]


After the third month, urethra also contributes to the development of associated structures depending on the biological sex of the embryo. In the male, the epithelium multiples to form the  prostate . In the female, the upper part of the urethra forms the urethra and  paraurethral glands . [ 18 ]


The urethra is the vessel through which urine passes after leaving the bladder. During urination, the smooth muscle lining the urethra relaxes in concert with bladder contraction(s) to forcefully expel the urine in a pressurized stream. Following this, the urethra re-establishes muscle tone by contracting the smooth muscle layer, and the bladder returns to a relaxed, quiescent state. Urethral smooth muscle cells are mechanically coupled to each other to coordinate mechanical force and electrical signaling in an organized, unitary fashion. [ 19 ]


The male urethra is the conduit for  semen  during  orgasm . [ 3 ]  Urine is removed before ejaculation by  pre-ejaculate  fluid – called Cowper's fluid – from the bulbourethral gland. [ 20 ] [ 21 ]


Infection of the urethra is  urethritis , which often causes purulent urethral discharge. [ 22 ]  It is most often due to a  sexually transmitted infection  such as  gonorrhoea  or  chlamydia , and less commonly due to other bacteria such as  ureaplasma  or  mycoplasma ;  trichomonas vaginalis ; or the viruses  herpes simplex virus  and  adenovirus . [ 22 ]  Investigations such as a  gram stain  of the discharge might reveal the cause;  nucleic acid testing  based on the  first urine sample passed in a day , or a swab of the urethra sent for  bacterial culture and sensitivity  may also be used. [ 22 ]  Treatment usually involves  antibiotics  that treat both gonorrhoea and chlamydia, as these often occur together. [ 22 ]  A person being treated for urethritis should not have sex until the infection is treated, so that they do not spread the infection to others. [ 22 ]  Because of this spread, which may occur during an  incubation period  before a person gets symptoms, there is often  contact tracing  so that sexual partners of an affected person can be found and treatment offered. [ 22 ]


Cancer can also develop in the lining of the urethra. [ 23 ]  When cancer is present, the most common symptom in an affected person is  blood in the urine ; a physical  medical examination  may be otherwise normal, except in late disease. [ 23 ]   Cancer of the urethra  is most often due to cancer of the cells lining the urethra, called  transitional cell carcinoma , although it can more rarely occur as a  squamous cell carcinoma  if the type of cells lining the urethra have changed, such as due to a chronic  schistosomiasis  infection. [ 23 ]  Investigations performed usually include collecting a sample of urine for an inspection for malignant cells under a microscope, called  cytology , as well as examination with a flexible camera through the urethra, called  urethroscopy . If a malignancy is found, a  biopsy  will be taken, and a  CT scan  will be performed of other body parts (a  CT scan of the chest, abdomen and pelvis ) to look for additional  metastatic  lesions. [ 23 ]  After the cancer is  staged , treatment may involve  chemotherapy . [ citation needed ]


Passage of  kidney stones  through the urethra can be painful. Damage to the urethra, such as by kidney stones, chronic infection, cancer, or from catheterisation, can lead to narrowing, called a  urethral stricture . [ 24 ]  The location and structure of the narrowing can be investigated with a  medical imaging  scan in which dye is injected through the urinary meatus into the urethra, called a  retrograde urethrogram . [ 25 ]  Additional forms of imaging, such as  ultrasound ,  computed tomography  and  magnetic resonance imaging  may also be used to provide further details. [ 25 ]


Injuries to the urethra (e.g., from a  pelvic fracture [ 26 ] )


Foreign bodies in the urethra  are uncommon, but there have been medical case reports of self-inflicted injuries, a result of insertion of foreign bodies into the urethra such as an electrical wire. [ 27 ]


Hypospadias  and  epispadias  are forms of abnormal development of the urethra in the male, where the  meatus  is not located at the  distal  end of the penis (it occurs lower than normal with hypospadias, and higher with epispadias). In a severe  chordee , the urethra can develop between the penis and the scrotum.


A tube called a  catheter  can be inserted through the urethra to drain urine from the bladder, called an  indwelling urinary catheter ; or, to bypass the urethra, a catheter may be directly inserted through the abdominal wall into the bladder, called a  suprapubic catheter . [ 28 ]  This may be to relieve or bypass an obstruction, to monitor  how much urine someone produces , or because a person has difficulty urinating, for example due to a  neurological  cause such as  multiple sclerosis . [ 28 ]  Complications that are associated with catheter insertion can include  catheter-associated infections , injury to the urethra or nearby structures, or pain. [ 28 ]


In all  mammals , with the exception of  monotremes , and in both sexes, the urethra serves primarily to drain and excrete urine, which in mammals, collects in the urinary bladder and is released from there into the urethra. In addition, the closing mechanisms of the urethra, together with  immunoglobulins , largely prevent germs from penetrating the inside of the body. [ 29 ]  In  marsupials , the female's urethra empties into the  urogenital sinus . [ 30 ]


The word "urethra" comes from the  Ancient Greek  οὐρήθρα –  ourḗthrā . The stem "uro" relating to urination, with the structure described as early as the time of  Hippocrates . [ 31 ]  Confusingly however, at the time it was called "ureter". Thereafter, terms "ureter" and "urethra" were variably used to refer to each other thereafter for more than a millennia. [ 31 ]  It was only in the 1550s that anatomists such as  Bartolomeo Eustacchio  and  Jacques Dubois  began to use the terms to specifically and consistently refer to what is in modern English called the ureter and the urethra. [ 31 ]  Following this, in the 19th and 20th centuries, multiple terms relating to the structures such as  urethritis  and  urethrography , were coined. [ 31 ]


Kidney stones have been identified and recorded about as long as written historical records exist. [ 32 ]  The urinary tract as well as its function to drain urine from the kidneys, has been described by  Galen  in the second century AD. [ 33 ]  Surgery to the urethra to remove kidney stones has been described since at least the first century AD by  Aulus Cornelius Celsus . [ 33 ]


The  urogenital triangle  is the anterior part of the  perineum .  In female  mammals , it contains the  vulva , while in male mammals, it contains the  penis  and  scrotum .


The urogenital triangle is the area bound by a triangle with one vertex at the  pubic symphysis  and the two other vertices at the  iliac tuberosities  of the  pelvic bone .


As might be expected, the contents of the urogenital triangle differ greatly between the male and the female. Some of the components include: [ 1 ]


The human  urinary system , also known as the  urinary tract  or  renal system , consists of the  kidneys ,  ureters ,  bladder , and the  urethra . The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, control levels of  electrolytes  and  metabolites , and regulate  blood pH . The urinary tract is the body's drainage system for the eventual removal of  urine . [ 1 ]  The kidneys have an extensive blood supply via the  renal arteries  which leave the kidneys via the  renal vein . Each kidney consists of functional units called  nephrons . Following  filtration  of blood and further processing, wastes (in the form of  urine ) exit the kidney via the ureters, tubes made of  smooth muscle  fibres that propel urine towards the urinary bladder, where it is stored and subsequently expelled through the  urethra  during  urination . The female and male urinary system are very similar, differing only in the length of the urethra. [ 2 ]


800–2,000 milliliters (mL) of urine are normally produced every day in a healthy human. This amount varies according to fluid intake and kidney function.


The urinary system refers to the structures that produce and transport urine to the point of excretion. In the human urinary system there are two kidneys that are located between the dorsal body wall and parietal peritoneum on both the left and right sides.


The formation of urine begins within the functional unit of the kidney, the nephrons. Urine then flows through the nephrons, through a system of converging tubules called collecting ducts. These collecting ducts then join together to form the  minor calyces , followed by the major calyces that ultimately join the renal pelvis. From here, urine continues its flow from the renal pelvis into the ureter, transporting urine into the urinary bladder. The anatomy of the human urinary system differs between males and females at the level of the urinary bladder. In males, the urethra begins at the internal urethral orifice in the trigone of the bladder, continues through the external urethral orifice, and then becomes the prostatic, membranous, bulbar, and penile urethra. Urine exits the male urethra through the  urinary meatus  in the  glans penis . The female urethra is much shorter, beginning at the bladder neck and terminating in the  vulval vestibule .


Under microscopy, the urinary system is covered in a unique lining called  urothelium , a type of  transitional epithelium . Unlike the  epithelial  lining of most organs, transitional epithelium can flatten and distend. Urothelium covers most of the urinary system, including the renal pelvis, ureters, and bladder.


The main functions of the urinary system and its components are to:


Average urine production in adult humans is about 1–2  litres  (L) per day, depending on state of hydration, activity level, environmental factors, weight, and the individual's health. Producing too much or too little urine requires medical attention.  Polyuria  is a condition of excessive urine production (> 2.5 L/day). Conditions involving low output of urine are  oliguria  (< 400 mL/day) and  anuria  (< 100 mL/day).


The first step in urine formation is the filtration of blood in the kidneys. In a healthy human, the kidney receives between 12 and 30% of  cardiac output , but it averages about 20% or about 1.25 L/min.


The basic structural and functional unit of the kidney is the  nephron . Its chief function is to regulate the  concentration  of  water  and soluble substances like  sodium  by filtering the  blood , reabsorbing what is needed and excreting the rest as  urine .


In the first part of the nephron,  Bowman's capsule  filters blood from the  circulatory system  into the tubules. Hydrostatic and osmotic pressure gradients facilitate filtration across a semipermeable membrane. The filtrate includes water, small molecules, and ions that easily pass through the filtration membrane. However, larger molecules such as  proteins  and  blood cells  are prevented from passing through the filtration membrane. The amount of filtrate produced every minute is called the  glomerular filtration rate  or GFR and amounts to 180 litres per day. About 99% of this filtrate is reabsorbed as it passes through the nephron and the remaining 1% becomes urine.


The urinary system is regulated by the  endocrine system  by  hormones  such as  antidiuretic hormone ,  aldosterone , and  parathyroid hormone . [ 3 ]


The urinary system is under influence of the  circulatory system ,  nervous system , and  endocrine system .


Aldosterone  plays a central role in regulating blood pressure through its effects on the kidney. It acts on the distal tubules and collecting ducts of the nephron and increases reabsorption of sodium from the glomerular filtrate. Reabsorption of sodium results in retention of water, which increases blood pressure and blood volume. Antidiuretic hormone (ADH), is a  neurohypophysial hormone  found in most  mammals . Its two primary functions are to retain water in the body and  vasoconstriction . Vasopressin regulates the body's  retention of water  by increasing water reabsorption in the collecting ducts of the kidney nephron. [ 4 ]  Vasopressin increases water permeability of the kidney's collecting duct and distal convoluted tubule by inducing translocation of aquaporin-CD water channels in the kidney nephron collecting duct plasma membrane. [ 5 ]


Urination, also sometimes referred to as micturition, is the ejection of  urine  from the  urinary bladder  to the outside of the body. Urine is ejected through the  urethra  from the  penis  or  vulva  in  placental mammals  and through the  cloaca  in other  vertebrates . In healthy humans (and  many other animals ), the process of urination is under voluntary control. In infants, some elderly individuals, and those with neurological injury, urination may occur as an involuntary  reflex . Physiologically, micturition involves coordination between the  central ,  autonomic , and  somatic nervous systems . Brain centers that regulate urination include the  pontine micturition center ,  periaqueductal gray , and the  cerebral cortex .


Urologic disease  can involve congenital or acquired dysfunction of the urinary system. As an example,  urinary tract obstruction  is a urologic disease that can cause  urinary retention .


Diseases of the kidney tissue are normally treated by  nephrologists , while diseases of the urinary tract are treated by  urologists .  Gynecologists  may also treat female urinary incontinence.


Diseases of other bodily systems also have a direct effect on urogenital function.  For instance, it has been shown that  protein  released by the kidneys in  diabetes mellitus  sensitizes the kidney to the damaging effects of  hypertension . [ 6 ]


Diabetes  also can have a direct effect in  urination  due to  peripheral neuropathies , which occur in some individuals with poorly controlled blood sugar levels. [ 7 ]


Urinary incontinence  can result from a weakening of the  pelvic floor  muscles caused by factors such as  pregnancy ,  childbirth ,  aging , and being  overweight . Findings recent systematic reviews demonstrate that behavioral therapy generally results in improved urinary incontinence outcomes, especially for  stress  and  urge  UI, than medications alone. [ 8 ] [ 9 ]  Pelvic floor exercises known as  Kegel exercises  can help in this condition by strengthening the pelvic floor. There can also be underlying medical reasons for urinary incontinence which are often treatable. In children, the condition is called  enuresis .


Some cancers also target the urinary system, including  bladder cancer ,  kidney cancer ,  ureteral cancer , and  urethral cancer . Due to the role and location of these organs, treatment is often complicated. [ citation needed ]


Kidney stones  have been identified and recorded about as long as written historical records exist. [ 10 ]  The urinary tract including the ureters, as well as their function to drain urine from the kidneys, has been described by  Galen  in the second century AD. [ 11 ]


The first to examine the ureter through an internal approach, called ureteroscopy, rather than surgery was  Hampton Young  in 1929. [ 10 ]  This was improved on by  VF Marshall  who is the first published use of a flexible  endoscope  based on  fiber optics , which occurred in 1964. [ 10 ]  The insertion of a drainage tube into the  renal pelvis , bypassing the ureters and urinary tract, called  nephrostomy , was first described in 1941. Such an approach differed greatly from the  open surgical  approaches within the urinary system employed during the preceding two millennia. [ 10 ]


The  bladder  (from  Old English    blædre  'bladder,  blister ,  pimple ') is a  hollow organ  in  humans  and other  vertebrates  that stores  urine  from the  kidneys . In  placental mammals , urine enters the bladder via the  ureters  and exits via the  urethra  during  urination . [ 1 ] [ 2 ]  In humans, the bladder is a distensible organ that sits on the  pelvic floor . The typical adult human bladder will hold between 300 and  500 ml  (10 and  17 fl oz ) before the urge to empty occurs, but can hold considerably more. [ 3 ] [ 4 ]


The Latin phrase for "urinary bladder" is  vesica urinaria , and the term  vesical  or prefix  vesico-  appear in connection with associated structures such as  vesical veins . The modern Latin word for "bladder" –  cystis  – appears in associated terms such as  cystitis  (inflammation of the bladder).


In humans, the bladder is a hollow muscular organ situated at the base of the  pelvis . In  gross anatomy , the bladder can be divided into a broad  fundus  (base), a body, an apex, and a neck. [ 5 ]  The apex (also called the vertex) is directed forward toward the upper part of the  pubic symphysis , and from there the  median umbilical ligament  continues upward on the back of the anterior abdominal wall to the  umbilicus . The  peritoneum  is carried by it from the apex on to the  abdominal wall  to form the  middle umbilical fold . The neck of the bladder is the area at the base of the  trigone  that surrounds the  internal urethral orifice  that leads to the urethra. [ 5 ]  In males, the neck of the urinary bladder is next to the  prostate gland .


The bladder has three openings. The two  ureters  enter the bladder at  ureteric orifices , and the  urethra  enters at the  trigone of the bladder . These ureteric openings have mucosal flaps in front of them that act as valves in preventing the backflow of urine into the ureters, [ 6 ]  known as  vesicoureteral reflux . Between the two ureteric openings is a raised area of tissue called the interureteric crest. [ 5 ]  This makes the upper boundary of the trigone. The trigone is an area of  smooth muscle  that forms the floor of the bladder above the urethra. [ 7 ]  It is an area of smooth tissue for the easy flow of urine into and from this part of the bladder - in contrast to the irregular surface formed by the rugae.


The walls of the bladder have a series of ridges, thick mucosal folds known as  rugae  that allow for the expansion of the bladder. The  detrusor muscle  is the muscular layer of the wall made of  smooth muscle   fibers  arranged in spiral, longitudinal, and circular bundles. [ 8 ]  The detrusor muscle is able to change its length. It can also contract for a long time whilst  voiding , and it stays relaxed whilst the bladder is filling. [ 9 ]  The wall of the urinary bladder is normally 3–5 mm thick. [ 10 ]  When well distended, the wall is normally less than 3 mm.


In males, the  prostate gland  lies outside the opening for the urethra. The middle lobe of the prostate causes an elevation in the mucous membrane behind the internal urethral orifice called the uvula of urinary bladder. The uvula can enlarge when the prostate becomes enlarged.


The bladder is located below the  peritoneal cavity  near the  pelvic floor  and behind the  pubic symphysis . In males, it lies in front of the rectum, separated by the  rectovesical pouch , and is supported by fibres of the  levator ani  and of the prostate gland. In females, it lies in front of the  uterus , separated by the  vesicouterine pouch , and is supported by the elevator ani and the upper part of the  vagina . [ 10 ]


The bladder receives blood by the  vesical arteries  and drained into a network of  vesical veins . [ 11 ]  The  superior vesical artery  supplies blood to the upper part of the bladder. The lower part of the bladder is supplied by the  inferior vesical artery , both of which are branches of the  internal iliac arteries . [ 11 ]  In females, the  uterine  and  vaginal arteries  provide additional blood supply. [ 11 ]  Venous drainage begins in a network of small vessels on the lower  lateral  surfaces of the bladder, which coalesce and travel with the lateral ligaments of the bladder into the  internal iliac veins . [ 11 ]