Describe the location and function of the reticular formation.?
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The reticular formation is located throughout the brainstem (midbrain, pons, medulla). It can be divided into two different parts, the ascending and descending reticular formation.\n\nThe ascending reticular formation is also called the reticular activating system. It is responsible for the sleep-wake cycle, thereby controlling the level of alertness. It also projects to the thalamus, which also plays a role in wakefulness. From there, information is sent to the cortex for further processing.\n\nThe descending reticular formation is involved in autonomic nervous system activity. It recieves it's information from the hypothalamus. It plays a role in motor movement, including posture and equilibrium. The descending reticular nuclei in the brain mediate reflexive behaviors like coughing, chewing, swallowing and vomiting.
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The choroid plexus is the area on the ventricles of the brain where cerebrospinal fluid (CSF) is produced.\n\nChoroid plexus is present in the superior part of the inferior horn of the lateral ventricles. It follows up along this boundary, continuous with the inferior of the body of the lateral ventricles. It passes into the interventricular foramen, and is present at the top of the third ventricle.\n\nThere is also choroid plexus on the fourth ventricle, on the section closest to the bottom half of the cerebellum.\n\nStructure of the choroid plexus\nThe choroid plexus consists of many capillaries, separated from the subarachnoid space by pia mater and choroid ependymal cells. Liquid filters through these cells from blood to become CSF. There is also much active transport of substances into, and out of, of the CSF as it's made.\n\n---OR--- (if you want another definition)--\n\nA rich capillary plexus develops in the connective tissue around the neural tube of the 6-8 mm embryo. The roofs of the prosencephalon and rhombencephalon are thin, composed of ependyma that becomes invaded by the capillaries. Ependyma plus pia mater is called tela choroidea; vascularized tela choroidea is choroid plexus (red).\n\nIn the adult, cerebrospinal fluid (CSF) is formed by choroid plexus in the 1) body and inferior horns of the lateral ventricles, 2) roof of the 3rd ventricle of the diencephalon, and 3) roof of the 4th ventricle in the medulla. Apertures in the 4th ventricle (foramina of Magendi and Luschka), which develop during the 3rd month, permit the flow of CSF from within the ventricles to subarachnoid spaces surrounding the brain and spinal cord.\nThe ventricle follows the cerebral hemisphere as it makes its “C”-shaped curve. The choroid fissure and its associated choroid plexus is at first on the thinned medial wall on the dorsal aspect of the developing hemisphere. Later, it continues into the roof of the medial aspect of the inferior horn of the lateral ventricle.\n\nhope that helps you!~
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It is unknown where in the brain dreams originate — if there is such a single location — or why dreams occur at all. However, there are many competing theories of the neurology of dreams.\n\nDuring a typical lifetime a person spends about 6 years dreaming[1] (which is about 2 hours each night[2]).\n\nThe activation synthesis theory developed by Allan Hobson and Robert McCarley asserts that the sensory experiences are fabricated by the cortex as a means of interpreting random signals from the pons. They propose that in REM sleep, the ascending cholinergic PGO (ponto-geniculo-occipital) waves stimulate higher midbrain and forebrain cortical structures, producing rapid eye movements. The activated forebrain then synthesizes the dream out of this internally generated information. They assume that the same structures that induce REM sleep also generate sensory information.[3] Memory, attention and the other features lacking in the dream state are taken to depend on the neurotransmitters norepinephrine and serotonin, which are present in reduced concentrations during REM sleep. This chemical change is hypothesized to produce a psychotic state, as well as a lack of orientation.
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usually at the centre. but sometimes lies in the periphal region if vacuole is too large(vacuole displaces the nucleus eg. in plant cell) \n    its size differs from cell to cell. however  its size is significantly larger than many other cell organelles like ribosome,lysosome, ER, etc but smaller than vacuole in plant cells
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The tapetum lucidum (note the spelling) has different characteristics according to the species. The color reflected depends on its structure but also on the color of the iris. \nFor instance, some bony fish, crocodiles, and marsupials have retinal tapeta (plural of tapetum). In other vertebrates the tapetum is in the choroid and may be formed by guanine (sharks), cells with refractive material (carnivores, rodents, cetaceans), or extracellular fibers (cow, sheep, goat, horse). The color varies with species, age, and amount of pigmentation in the eye and skin (including fur color); see figure 2 in the paper at the link.\nSo the answer is yes, there are different colors of tapeta lucida; and no, the red color is not an indication of "wild" animals. In fact, many animals that are diurnal and lack a tapetum lucidum (for example primates, squirrels, birds, pigs) show a red or orange reflection. \n\nSee this review article (free access) for more information:\nhttp://www.blackwell-synergy.com/links/doi/10.1111%2Fj.1463-5224.2004.00318.x
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Well, the Organ of Corti is the hearing organ inside the ear. It sits on top of the basilar membrane. It has supporting cells, hair cells with stereocilia (even tinier hairs) on top. The stereocilia are connected together through tiplinks, and these tiplinks sit on top of ion channels. Above this structure is the tectorial membrane. It's a brief description.
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juxtaposition juxtaglomerular juxtaposit
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The sympathetic nerves arise in the brain in the reticular formation, a diffuse set of nuclei (cell bodies in the brain or spinal cord) and send axons (bioelectrical transmission lines) the the lateral horn of the spinal cord.  The reticular formation receives incoming pain signals as well as higher input from the hypothalamus, cortex and elsewhere.  The axons descending to the lateral horn snynape (form chemical connections that communicate with the next neuron by chemicals known as neurotransmitters) with the cell bodies of motor neurons.  These motor neurons send myelinated (myelin is a biological insulator) axons to the ganglia (collections of cell bodies outside the brain and spinal cord) for the sympathetic nervous system.  These ganglia include a long chain that entends from the cervical to the lumbar regions, plus other ganglia in the head and adbominal cavity.  This synapse typically releases the neurotransmitter, acetylcholine, which acts on nicotinic type "N" receptors - nicotinic-ganglionic receptors.   Nicotinic "N' receptors are distinguished from nicotinic "M" receptors (the neuromuscular junction) that serve skeletal muscle by differing responsiveness to pharmacological agents.  The post-synaptic (cell that receives the chemical signal) neurons are not mylenated and project to the visceral organs, skin, and blood vessels where they release neurotransmitters (norepinephrine or, in the case of skin, acetylcholine) that act on the effector organs.
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It’s pretty much where excitatory and inhibitory signals are summated.  If there is enough stimulation to reach threshold the neuron fires an action potential here.  This is basically the first domino of a whole line.  Once it goes the signal travels down the rest of the axon, but this is where it starts.
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http://ajpregu.physiology.org/cgi/content/full/280/5/R1388
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The photoreceptors are located in the retina of the eye.  The outer segments of the photoreceptors are responsible for catching photons of light, which initiates an electochemical signal that ultimately results in vision.  There are two main types of photoreceptors, rods and cones.  Rods are responsible for vision in lower light levels, while cones are responsible for color and most form recognition.  Rods are dispersed throughout the retina, while cones are most densely packed in the region of the retina responsible for your central, or "straight ahead," vision.  This area is called the macula.  In fact, the center of the macula, the fovea, contains only cones, and they are very densely packed in this area to allow for higher resolution of fine detail.
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The cerebrum, the cerebellum, and the brain stem.  Check out these websites for more detailed information.\n\nI hope this helps.
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I looked this one up in my neuroscience book. Thought I'd add to the above answer. \n\nIt looks like it is hierarchical because of the motor subsystems. Two of these subsystems are Lower and upper motor neurons. Upper are located in the brainstem or cerebral cortex while lower send axons out of the brainstem and spinal cord. Third and forth subsystems regulation teh upper motor systems. Third, cerebellum, forth basal ganglia. \n\nThe interactions are more detailed and too much to type. Good luck. \n\nBTW: I like these sorts of questions.
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The lunate sulcus separates the primary visual cortex from the rest of the brain - in homo erectus and primates
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Do you mean the molecular composition or macroscopic composition? There would be too much to post here so I suggest you visit the following\n\nhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/Blood.html#formation
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The risorius crease is formed next to the risorius muscle near the jaw.  The Risorius starts at the back of the jaw, and pulls on the corner of the mouth.  \nMRI studies have confirmed the location in the brain for the triggering of this muscle.  The text that goes with the scan is:\n\n“Top row shows a control subject alternating rest with unilateral (right) contraction of the risorius, a lower face muscle. Activation is approximately equal in the right and left primary sensorimotor cortex.”\n\nThis appears to be near the temple area.  For the actual pictures see the reference site below:
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Each facet is known as an ommatidium and they are located within the large compound eyes found on the head....\n\nIm not sure this was a serious question, but you get a serious answer regardless