How many nerves are in the human body?

Answer 1

There are many many millions of single cell neurons. It is estimated that there are up to 100 billion neurons in the human brain. It is likely that there are more neurons in the human body than any other cell type. many neurons are in the brain others are in tracts or organised pathways within the brain and spinal cord. Outside this central nervous system there are the larger most common obvious collections of individual cells that all follow the same or similar anatomic route through the body (within a single outer connective tissue pipe or sheath); for example the sciatic nerve and the radial nerve. These are the 'nerves' named and accepted by the medical community. There are three main types of nerves and, according to Wikipedia, 214 named nerves. However a biologist will soon point out there are many unnamed nerves, such as those that run to small sensors in the skin or the periosteum, and many that are repeated many more times than twice (the intercostal nerve for example). There is also a high level of personal differences in the actual neuronal anatomy of the content of named nerves so one persons sciatic nerve will not have exactly the same number neurons as the next. Neurons that commonly exit at one particular level in the spine may also in some persons exit at a higher or lower level in others. So the answer in fact must be that there are many thousands, but quite possibly millions, of bundles of smaller unnamed groups of neurons that are clearly small nerves, but medically there are the predictable larger nerves - 214 of them. It is said that there are enough neurons in the human body that if all the other cells were somehow removed the network of fine smaller nerves and neurons would be numerous enough to enable you to easily recognize the individual concerned and to recognize every tissue layer in his or her body. Finally it should also be pointed out that nerves do not supply cells or parts of the body - neurons do. Nerves are basic anatomical pathways acting as conduits within which are the real active components of information transmission - the neurons. There is perhaps just one nerve to any given muscle but this will contain perhaps a thousand neurons. each neuron branching at its end to supply thousands of muscle cells with their individual signals.