How the Body Works : Anatomy of a Nerve

Anatomy of a Nerve

More than ten thousand million nerve cells and their fibers, or axons, make up the nervous system. The axons are grouped together in nerve trunks containing sensory fibers, which conduct information from the sensory organs to the central nervous system, and motor fibers, which carry information to the central nervous system of the body. The nerve fibers which carry information quickly are enclosed in a thick sheath made of the fatty substance myelin. They are called myelinated nerve fibers. The myelinated sheath has regular indentations along its length called the nodes of Ranvier. The nonmyelinated nerve fibers, which carry information slowly, are grouped together and enclosed in a single sheath.

The anatomy of a nerve includes: the cell body, which is composed of cytoplasm and contains the cell nucleus; the nucleus, which contains the information needed to control the activity of the neuron; the dendrites, outgrowths of the cell body to which and from which they conduct impulses; the epineurium, a fibrous sheath that surrounds the whole nerve; the perineurium, the connective tissue sheath that surrounds bundles of nerve fibers; the endoneurium, the fine sheath of connective tissue around each nerve bundle; the axon, the extended fiber of the nerve cell which carries impulses to and from the cell body; the fatty myelin sheath, the insulating coat that separates the axon in a nerve bundle; the Schwann cell nucleus, the mechanism responsible for the production and maintenance of the myelin sheath and the Nodes of Ranvier, constrictions in the myelin sheath.

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[creamtornado]

most boring voice ever!

[kanyewestsucks12]

*Correction* axons only carry info efferently (away from the cell)

[AlexHop1]

Very helpful and clear video. Thank you!

[godlameroso]

@kanyewestsucks12 Not true, there is simply insufficient research on the topic to say one way or the other.

[Nat4Brendan]

I actually like this guy's voice. xD

[YurNotSpecial]

@kanyewestsucks12 If you said axons only carry info away from the cell, you would be correct. The terms afferent and efferent refer to axons arranged to send action potentials to or away from the CNS respectively. Of course, you would only be correct assuming info = action potential; signaling does in fact go both ways in an axon.

[AtziluthLVX]

@kanyewestsucks12 that's not entirely true. there is something called retrograde transport.

[eddiefromnyc]

sucky video for this i rather listen in class while teacher is lecturing

[torrentgray]

im gonna fall asleep before i finish this video.

[ukes]

@kanyewestsucks12 *correction* some axons are found in the ascending tract of the spinal cord, which carry Afferent information to the brain

[SG02JATT]

what a horrible fucking video