Nov
29
2006

Question for Dave Lee

I'm new here and want to ask a question - not write a short story. If this is the wrong place for a question, please help me out.

Is the human egg really the largest cell in the body? That's what the human body movie said. But isn't a neuron a cell, and isn't the axon a part of it, so that a single neuron can be a yard long - as in the sciatic nerve? Wouldn't that be larger than an egg cell?

And while i'm at it, here's a comment: The movie said that the brain controls the GI tract, but my understanding is that although the brain can influence your stomach and bowels, through emotions for example, the GI tract operates pretty much on its own. In fact, Dr. Michael Gershon calls the GI tract "The Second Brain" in his wonderful book by that title.

All in all, i thought the movie was fantastic, and wish there had been much, much more of it!

Your Comments, Thoughts, Questions, Ideas

bryan kennedy's picture

Hi McTwoddie, thanks for your question and yes, this is a perfect place to post something like this. We've sent your query to our Human Body experts and they should be posting soon. Welcome to the Buzz.

posted on Wed, 11/29/2006 - 5:15pm
Liza's picture
Liza says:

I posed your questions to Ana Kaveh, who runs the Human Body Gallery here at SMM. Here's her answer:

"My quick answers are

  1. the axon is not part of the cell body, just a process of it, so even though an axon can be really long, the egg is bigger than the main cellular part of a neuron, and
  2. yes, the digestive tract does a lot on its own, but the brain does still have some influence over it. For example, the vagus nerve that originates from the medulla connects to, amongst many other things, the digestive tract and plays an important role in how it functions."
posted on Thu, 11/30/2006 - 11:35am
McTwoddie's picture
McTwoddie says:

Thanks, Bryan!

posted on Wed, 11/29/2006 - 10:13pm
Anonymous's picture
Anonymous says:

i think people shoold not watch tv because it rots your brain but there can be educational stuff on tv.

posted on Thu, 11/30/2006 - 4:20pm
McTwoddie's picture
McTwoddie says:

Thanks very much Liza. I think I understand the terminology. The length of a woman's hair is not added to her height. This analogy is obviously not exact. An axon transmits information; a hair just glints in the sunlight. (Which could be information of importance to someone - but I digress.)

My other remark was just a quibble; part of my wish that the movie had been much, much longer. Long enough to include the autonomic nervous system, for example.

posted on Thu, 11/30/2006 - 5:28pm

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