how would you decide if a peice of tissue came from the brain or form a peidce of muscle?
141002
It would depend on the muscle.  There are three types of muscle in the human body: (1) Skeletal muscle, which moves the bones; (2) smooth muscle, which surround organs and do not work under our conscious control, and (3) cardiac muscle, found only in the heart.  Both types (1) and (3) do have a special, distinct appearance under the microscope which will definitely distinguish it from brain tissue - it will have a stiped, zebra-like appearance (which in type (1) are actually named "Z-lines") due to how these types of muscle are constructed.  In type (3), which is also called myocardium, the striped appearance is due to these little disks that connect one heart muscle fiber to another, like a chain.\n\nThis is something that distinguishes muscles from almost anything else I've seen under a microscope.  So, look for the stripes!  I hope this helps.
1017475
The plug on the end that goes into the wall!\n\nThe real answer is that every component is as important as the other.\nJust go in and snip a wire or a resistor for fun.\n\nIf I leave my brain at home I can't function, can I? Is the brain the most important organ in the human body? What if I leave my liver at home.  Soon I'm dead. How about I leave my stomach at home and go to a Chinese buffet. Gads what a mess I'd be in! So is the brain more important than the liver or stomach. Me thinks not. For any complicated organism or device to work it needs all it parts so each part is as important as the other.
206623
Genetics determine the structural capacity of the brain, but the later development of neuroconnections depends on how stimulated the brain is.  stimulation comes from the interaction with environment and from biological factors such as diet and metabolism.  \nHowever, we are still wondering what is intelligence, so we should start there.
470666
1. nerve\n2. connetive tissue\n3. epithelium\n4. muscle (if you cut deep enough)
119709
Imagine the body as a loaf of bread and you are looking at one end of the loaf. As you remove each slice of bread, you can see the entire surface of that slice from the crust to the center. The body is seen on CAT scan slices in a similar fashion from the skin to the central part of the body being examined. When these levels are further "added" together, a three-dimensional picture of an organ or abnormal body structure can be obtained.
28671
This is impossible. 1) What species?\n2) To what stage? Age? etc.\n3) Too many factors to take into account\n4) No way to count.\n\nResearch into frogs and fish have very accurately mapped each stage of embryologic development. Past a certain point, even with dissection and microscopes it is impossible to tell for sure as the brain and nerves alone are so complex and have so many cells it is impossible to count them all.
557487
They come from the stem of the brain.
406196
It is tissue (i.e. cells) obtained from foetuses, often used in medical experiments.
842289
In what respect?\nYet more general questions asked by inquisitive ... erm.... well... I shall try to answer...\n\nThey are both substancial collections of atoms... formed into molecules... mostly water though a fair number of hydrocarbons and amino acids, among other similar structures. \nThey're both animal cells...  presumably human animal cells in this case... That means they have a cell membrane, nucleus, mitochondria and various smaller organelles.\n\nAside from that, we have the specifics of those cells:\nThey're both rather skinny for one thing... lengthy and skinny. Neurones... i.e. nerve cells.... can however be easily as long as the entire length of your forearm... and yet thinner than most cells. Sperm are very much smaller than that. \n\nFeature-wise... nerve cells have dentrites... branching extensions of the cell membrane... at each end. These are to connect to other neurones and transmit signals between them. The signals are transferred through the cell itself along the axon... which is the long, thin bit in the middle.... by means of an ionic differential gradient between potassium and sodium ions. In almost all cases, neurones will be found in bundles (since they're so thin) to cover a wide area and send as much data as possible to and from the brain.\nThere are different kinds of neurones that serve different functions.... in particular motor neurones (which transmit data from the brain to the body)  ... well... whatever the opposite ones... sensory neurones maybe... (which, by whatever name, transmit data from the sensory organs to the brain)... and interneurones... which join the others together inbetween.  As I recall, the neurones in the brain are of different types again, but I don't know the slightest thing about those.\nAnyhow... I don't think I can tell you much more about nerve cells.\n\n\nSperm on the other hand... are male gametes.... produced in vast numbers at very little bodily expense per cell. Each one is basically just a haploid nucleus (one copy of each chromosome) with a flagellum (a 'tail' to propel the cell forward) and just enough cytoplasm and mitochondria to power it for a short journey. They are generated at quite an alarming rate in the testes.... and their entire purpose is to be ejaculated into the female reproductive system and propel themselves forcefully and rather erratically to an awaiting ovum.... Eventually, of the ones that reach the ovum (most die along the way due to the corrosive substances which coat the inside of the uterus), one will get chemically accepted by the larger cell and allowed to fuse the cytoplasms together. The nuclei will then fuse into a single diploid (2 of each chromosome) nucleus.... and the newly fertilised cell will begin to divide.  Note however that while the nucleus of the sperm is allowed to fuse with the nucleus of the ovum... the mitochondria that are in the sperm will be destroyed by the new host cell.... hence all the mitochondria you will ever have are near-identical copies of your mother's ones (not perfect copies since mutations can and will occur between generations).\n\n\nRight... I've had enough of answering this question now...\nOff to other things.
825946
http://en.wikipedia.org/wiki/Muscle\n\nYour answer is described in detail on the above site, too long to paste here, but I am sure that you will get your answer from this site.
98933
Hmm Many great websites on biology have you looked any up? Start there does your text book have any resources for online help? Try that!! Cell = Tissue = Organ?
112685
Isn't this something they're trying to teach you at school? Think of the origins and insertions of these muscles, and of the movements achieved when each muscle layer contracts. Look at the pictures in any good Comparative Anatomy book and check the difference between the muscles of fishes and tetrapods (hint: new feature- lungs).
196064
A simple answer to a vague question:\n\nMostly the brain is soft.  The areas of a healthy brain that are "harder" would be the areas that have a higher density of cells, or cell processes.  For instance, the white matter in the brain are areas where cells arms (axons) are packed tightly into a highway traveling to another part of the brain or heading south to eventually become the spinal cord.  These areas are "harder" or more dense compared to the cortex areas (gray tissue) where the cell bodies sit.\n\nIn diseased brain tissue areas can become extremely dense.  A good example is when tumors form.  These can be round balls of cells all clumped together.  Another example is when people have Alzheimer's disease, their cells produce amyloid plaques - or a hard crystallized by-product that ends up collecting in areas like the hippocampus (responsible for memory).  These "hardened" areas interfere with normal brain functions like remembering stuff.\n\nNow, as for texture.  The brain areas I have felt all are smooth, wet, and feel very similar.  There is a fatty layer over most neurons (nerve cells) called myelin.  It makes most brain tissue feel buttery.\n\nI hope this answers your question, but I wonder why you ask it.
649112
The brain is an organ of the body, like any other organ, in that it has a distinctive structure and tissue types specific to the brain.  Thus, it is a biological entity.  Psychology is a study of our mental processes and behaviour, not the actual biology of the brain organ.
141972
Agree with Mr. Brightside, the person before me.\n\nMuscle tissue is a group of muscle cells.\nMuscle tissue is what generally called as "meat" or "flesh".\nMuscle tissue is the most abundant tissue in the body.\nIt is composed of cells called muscle fibers.\n\n3 types of muscle tissue:\n\n1. Smooth muscle\nIt can be found in intestines, blood vessels, urinary and reproductive tracts.\n\n2. Skeletal muscle\nIt can be found in arms and legs.\n\n3. Cardiac muscle\nIt can be found in the walls of heart.\n\nSMOOTH MUSCLE\nContraction and relaxation of smooth muscles are responsible for involuntary body activities such as peristaltic movement along the digestive tract.\nSmooth muscles contract more slowly than skeletal muscles but remain contracted for a longer period of time.\n\nSKELETAL MUSCLE\nSkeletal muscles are involved in volutary movements. They contract and relax to move the bones.\n\nCARDIAC MUSCLE\nCardiac muscle contract to pump blood to all parts of the body. The contraction of cardiac muscles is involuntary.
632354
I think it's protein. Because most of the human organ need protein to be form. The human organ, including heart are consist of cells, and they need protein to regenerate, I think this also happens when they were formed in fetus period.
209657
The debate still continues as to whether we do or do not, or, did or did not. \n\nEvolutionists believe we did and still do in the shape of a 'vestigial organ'; i.e. the coccyx (tail bone). A 'vestigial organ' is an organs that is supposed to represent useless remnants of what were once functional and useful organs in our primitive ancestors. Those who disagree claim that this tail bone is nothing of the sort and is a necessary part of present human anatomy and was never a tail in the true sense and definition.\n\nExamples:\n\nThis from Wikipaedia:\n\nHuman embryos have a tail that measures about one-sixth of the size of the embryo itself. As the embryo develops into a fetus, the tail is absorbed by the growing body. Infrequently, a child is born with a "soft tail", which contains no vertebrae, but only blood vessels, muscles, and nerves. Modern procedures allow doctors to eliminate the tail at delivery. The longest human tail on record belonged to a twelve-year-old boy living in what was then French Indochina, which measured nine inches (229 mm).\n\nThis from the MAFC:\n\nAll true tails have bones in them that are a posterior extension of the vertebral column. Also, all true tails have muscles associated with their vertebrae which permit some movement of the tail. Ledley conceded that there has never been a single documented case of an animal tail lacking these distinctive features, nor has there been a single case of a human caudal appendage having any of these features. In fact, the caudal appendage Ledley described is merely a fatty outgrowth of skin that wasn't located in the right place on the back to be a tail!\n\nAh - the richness of human debate.