Our brain is made of how many nerves?
145324
The brain tissue surrounding the ventricles is far from homogeneous, but can be separated into a number of connected but distinct parts. It is dominated by the massive cerebrum, or forebrain, divided neatly down its mid-line into two almost mirror-image halves, linked by a massive band of nerves, the corpus callosum. Below the cerebral hemispheres lie the mid- and hind-brains. For the first 3-4 mm below the wrinkled surface of the cerebrum the tissue is coloured pinkish grey, forming the cortex (meaning “bark”); below that, it is yellowish white. The colour of the cortex is due to its extremely rich blood supply—fully 20 per cent of circulating blood goes to supply the brain. By contrast the “white matter” is so because of the fatty sheaths, composed largely of myelin, which insulate the nerves packed inside. The geography of the cerebral cortex, defined by its ridges and clefts (sulci and gyri) provides a distinction between left and right, frontal and occipital lobes. The regions towards the mid-line are medial, towards the sides temporal, the top, dorsal, and the bottom, ventral.\n\nBehind the cerebrum lies the even more wrinkled and folded cerebellum (“little brain”) covered with its own cortex. Visible as the brain is dissected are a number of distinct structures named by the anatomists after their fancied resemblance to other natural forms—the hippocampus (seahorse), amygdala (almond), pons (bridge), medulla, and many more. Running down from the medulla and through the spine is the spinal cord, carrying nerves to (afferent) and from (efferent) the brain itself. Nerves to and from the eyes (optic), nose (olfactory), and also cranial nerves to other regions of the head run directly into the brain, not via the spinal cord. Together, brain and spinal cord form the central nervous system (CNS), to distinguish them from the nerves that connect the brain and cord with the rest of the body, called the peripheral nervous system. Because of the bilateral symmetry of the brain, each of the structures within it seemed to the early anatomists to be duplicated, one to the left and one to the right. The exception seemed to be the pineal gland, located in the centre of the brain, and it was in part because of this that Descartes, whose dualist philosophy firmly separated the human soul from the mere clockwork processes that ran the rest of the body, decided that the pineal must be the site at which the soul or mind interacted with and drove the body forward. Non-human animals, which were believed not to possess souls, he saw as entirely machine-like.\nThe current view of the brain is of an organ composed of a large number of substructures, each densely packed with neurons and their surrounding glia. Within each nucleus, and within the cerebral and cerebellar cortices, neurons are of three general types: some receive inputs from either sense organs or other brain regions; others (projection or pyramidal neurons) transmit signals out of the region, down long axons to other brain regions or, via the spinal cord or cranial nerves to the periphery. The third and much the most numerous class are the spiny or stellate interneurons, which communicate only within a particular nucleus or cortex, either with one another or with the afferent and efferent neurons.\n\nFor modern localizers, these different substructures are regarded as “centres” for particular brain functions. Of particular importance are a group of connected nuclei including the hypothalamus, hippocampus, some nuclei of the thalamus, and the amygdala, sometimes grouped together as the limbic system. These centres are particularly relevant in the context of emotion, sexual drive, hunger, and thirst, and damage to them can have profound effects. The hypothalamus also has direct neural connections with the pituitary gland at the base of the brain, the source for many important regulatory hormones, and hypothalamic-pituitary feedback processes provide a key site for
1167864
not everything about your life is decided at birth. human brain is made up of milllions of neurons connected through axons and dendrons at locations called synapse. At the time of birth, each individual cell is connected to almost every other cell in the vicinity. but as we grow up the redundant connections are done away with while the rewuire connections are strengthened . this process is determined to a large extent by how much that particular part of brain is used. so even if both the childs neurons may be likewise prorammed by genecode to do away with redundant connections the environment decides whose required connections are more effective.
463192
We use 100% of our brain-or at least 100% of our brain sense signals and uses oxygen and glucose.  Any neuron which does not connect with another and depolarize occasionally will probably die.  I have no idea where this myth came from, unless it was from studies of learning and memory.  We can learn a great deal more than most of us do-any average person could learn multiple languages, become expert in a number of fields, etc, but we don't.  This doesnt mean we dont use our brains-learning is more likely the generation of new pathways, connections, etc.  So it may be that we only learn 10% of what we could (put this way, it would be closer to 1%).  The majority of the brain is set aside for motor and sensory system integration- It takes an enormous amount of brain power to just perform our normal movements and to interpret and filter all the huge amount of sensory information we get every second-*That* is the primary action of the cortex.
469364
We use all of our brains.  It is a myth that we do not.
560363
It is only my theory, but I think it predates written history.  Biologically speaking our lips and tongues have alot of nerve receptors and take up a substantial amount of "brain space".  So it is kinda like we were made to kiss.\nFYI, there are alot of nerve receptors in the genitals and hands as well.
928361
Ok- both sides of the brain are "identical" when it comes to nerves.  If it's on one side, it's on the other side in the same place (mirror image).\n\nDiagrams and images only point to one to save space and keep the page from getting messy with lines.\n\nHope this helped.
592954
Spinal cord\nPeripheral nerves\n\nThere are many peripheral nerves, and many subdivisions in the brain, too. Too many to list, since they cover every inch of your body and every organ system as well.
897254
1. Nerve anatomy: nerves are axons of a neuron, enclosed by myelin, and are part of the peripheral nervous system. Afferent nerves carry sensory information from the body to the dorsak root ganglia of the spinal cord and then to the brain (although cranial nerves go directly to the brain). Efferent nerves carry motor information from the brain to the body (muscles) to contract or relax. \n\n2. Reflex architecture: reflex arc. Sensory info (i.e. pressure) activates specialized sense receptors-->sends afferent signal to dorsal root ganglia of spinal cord-->sends info to interneuron-->sends info to ventral root-->sends efferent info to muscle-->muscle contracts (or relaxes, muscles work in pairs).\n\n3. Embryo forebrain-->telencephalon (cerebral cortex, basal ganglia, and limbic system). Midbrain-->Mesencephalon (thalamus, hypothalamus). Hindbrain-->metencephalon (cerebellum and pons) and myelencephalon (medulla oblongata).\n\n4. Functions of what?\n\n5. Hearing: consists of outer, middle, and inner ear. Outer ear is ear canal, middle ear is the ear drum and 3 smallest bones in body (hammer, anvil and stirrup), inner ear is the cochlea. Sound waves travel through the canal, cause the ear drum to vibrate, which moves the 3 bones, which causes the fluid in the cochlea to move, which activates the hair cells (receptors) that send infor to the auditory cortex in the brain.\nVision: from the outer eye to inner eye, you have cornea, iris, pupil, lens, vitreous humor, and the retina (which has the receptors). Within the retina, you have photoreceptors, bipolar cells, ganglion cells, and amacrine cells. Photoreceptors are rods (light) and cones (color). From the ganglion cells, information gets sent to the primary visual cortex in the brain.\n\n6. The spinal cord is long tube protected by vertebral column. It has white matter (axons or nerves from above definition) on the outside and gray matter (cell bodies) on the inside. The gray matter kind of looks like a butterfly in the spinal cord.\n\n7. Cerebellum: coordinated movement\nThalamus: sensory relay station\nCerebrum: divided into 4 sensory lobes, performs several higher functions such as language, emotion, and memory.\nHypothalamus: controls autonomic nervous system and endocrine systems (4 F's: fighting, feeding, fleeing, and mating...)\nMedulla: controls vital functions (cardiovascular, respiration, and skeletal muscle tone).
386668
Average number of neurons in the brain = 100 billion\nAverage number of glial cells in brain = 10-50 times the number of neurons
873081
The two answers that you see most often are nerve cell and ovum.\nBoth are correct.\n1. the nerve cells that make up sensory nerves have their cell bodies in the dorsal root ganglion located in the back and the have extensions (dendrites) that reach to the area sensed (all the way to the toes. (many millimeters long but very, very thin).\n2. The cell body of the ovum is the round and had the largest volume of any cell.
138371
It is the seat of the intellect, not an intellectual organ.  All cognition (thought, logic, creativity, etc) is initiated in the brain.
632985
The brain is part of the nervous system.  The smallest component of the nervous system are axons, which have a head and a tail.  Millions of these line up head to tail and form the nerve endings in your body.  In the space between each head and tail (called a synapse) chemicals can flow.  When something happens (you prick yourself), an axon signals chemicals to flow between the synapse, activate the next axon, and the next until the message reaches your brain and you react.  Different drugs affect the ability for these chemicals to flow across the synapse (speeding up, slowing down, or not at all) or wipe out axons all together leaving gaps in the message chain.
128391
Very roughly, in ascending order of complexity:\n\nC.Elegans:  ~300 neurons\nDrosophila: ~100 thousand neurons\nRat:   ~100 million neurons\nHuman: ~100 thousand million neurons
376079
We *can* use 100% of our brain. This is a very strange, but common misconception. All parts of our brain have various functions and all are used. \n\nThe likely source of this myth is the discovery long ago that only about 10% of our neurons are firing at a time. That does not mean only ten percent fire ever, but on average, that is how many fire at any given time.   On that line of thinking, if 100% of our neurons were to fire at once, we would be having a severe seizure.
507453
Yes.  The human mind is just an incredibly complex computer which can manufacture it's own connections.  All we need to do is get the software and hardware sides of our current technology up to the level of our brains and beyond...  Easier said than done, I know.
900447
A) Cell bodies is my choice.\n\nCerebral cortex  is a thin, convoluted surface of the brain consisting mainly of nerve cell bodies.♥
574722
Your brain is mostly damaged in the part where a certain part of the spinal cord is damaged. Neurons do not regenerate. They get killed and don't come back. Nerve cells don't normally regenerate themselves.