How may nerve cells are in a nerve?


I’m so confused that I can’t figure this out. I heard that a motor neuron is a single cell, so does this mean that, for example, I move my foot, that is literally just 1 neuron with a long axon connecting from my foot to brain?

Or is a nerve just a bunch of neurons chained together?

When I look at pictures of neurons it just looks like a big web of wires so it being just 1 cell wouldn’t make sense?

Can someone please explain?

In: 4

1) Each single neuron has tree-like fingers coming out of it to send and receive information to and from up to 10,000 other neurons. That’s what creates the neural “webs” you see in illustrations. But where a neuron receives info and where it relays that info can be very close or very far. Thus….

2) A single neuron, depending on its type, may be very long or very short. They “relay” together to bring info to your brain. The longest single neuron in the body is part of the sciatic nerve going from the base of your spinal cord to your big toe (not only your longest neuron, but the longest single cell in the body!). Short “interneurons” connecting neurons to other neurons may be super short, only tenths of a millimeter.

3) A neuron is a single cell. As a long neuron travels from one part of the body to another, it is traveling next to other neurons. The “axons” of these individual neurons group together as they travel into a “nerve bundle.” Multiple nerve bundles are surrounded by connective tissue and blood vessels to create a “nerve”.

Hope this helped!

Re: your question about motor neurons specifically.

A Motor Unit is all the muscle fibres connected to a single nerve cell. But an actual muscle, like say, the quadriceps in the front of your thigh, will have millions of Motor Units that activate at the same time in order to produce the force needed.

Some motor units are smaller with fewer muscle fibres and are used for your normal day-to-day movements, like walking, while some motor units are large and are only recruited when you need to produce large amounts of force, like jumping