Nervous Transmission in the Human Body: Biology Resources

[Hootenanny]

As part of my (Math&Physics) course I am required to prepare a short report into a subject relating to Electomagnetism and to give a short presentation. My appointed topic is nervous transmission in the human body. Now, I have done no biology for a while (since A-Level) and was wondering what the standard texts are for a Biology course. Of course my report as presentation will be heavily geared toward Physicist but I would like to make sure I get the basic Biology correct. The report doesn't need to be significantly technical; something similar to Scientific America should do. Can anyone recommend any texts or resources? unfortunately, I don't know anyone in the Bio dept. (I don't even know where it is)

 

[berkeman]

Isn't nerve transmission mainly chemical, rather than electromagnetic? The firing and re-uptake across the synapses mainly occur via ionic movement, I believe (but I know very little about it). Was this topic given to you as an EM topic, or did you chose it out of personal interest? Just checking to be sure that you can get full credit for the report, given the overall topic of EM.

 

[Hootenanny]

Isn't nerve transmission mainly chemical, rather than electromagnetic? The firing and re-uptake across the synapses mainly occur via ionic movement, I believe (but I know very little about it). Was this topic given to you as an EM topic, or did you chose it out of personal interest? Just checking to be sure that you can get full credit for the report, given the overall topic of EM.

There are a few recommended topics that are broadly connected with EM, this is the one I given (others included Particle acceleration using Lasers, a Biography of Tesla's scientific/engineering achievements etc.). From what I remember from college (I took Bio and Chem) I would agree with you that the majority of nervous transmission occurs through ionic movement. So in retrospect I wouldn't mind some comments from Chemists at this point. This assignment is part of the EM module so I guess it should be focused on the EM aspects of the subject... The particle acceleration topic is looking more attractive at this point .

 

[berkeman]

The particle acceleration topic is looking more attractive at this point .

Yeah, particle acceleration via laser sounds exciting! Do you have any web pointers?

 

[Hootenanny]

Yeah, particle acceleration via laser sounds exciting! Do you have any web pointers?

Unfortunately not, we are just given a sheet outlining the presentational requirements. There's no panic though I've got about a month and a half before it has to be handed in so I'm sure I'll be able to get enough research done; but any book recommendations from Biologists of Chemists would be more than welcome.

 

[Hootenanny]

Thanks for all the help guys

 

[marcusl]

Chemistry isn't the place to go, head for the physiology section of your library or go to the med school library. Nerve fibers "depolarize" just like muscle fibers; there's an inrush of sodium ions radially inward across the fiber membrane that changes the relative potential of inside versus outside. This propagates down the axon (think cylinder) away from the bulk of the cell body. There's a strong electric field between the depolarized portion and the polarized (resting) downstream part that then triggers the downstream part of the membrane to depolarize, thus propagating the signal further. People have used the EE's telegraphy equation (transmission line) to model the propagation. As you read, you'll learn about the sodium pump, the role of the myelin sheath in speeding up propagation, and other amazing stuff. Hodgkin and Huxley won a Nobel for figuring out the basics.

The propagating ionic "wave" represents a current flow and generates electric fields that cause potential differences at the skin. In the brain, we measure them as the EEG. They're weak, both because of the smallness of the current and the fact that it flows in physically small loops that are seen from a great distance. You can also pick up extremely weak magnetic signals, the MEG; they have the advantage of good localization ("direction finding") since the field is directly related to the source without the conduction and smearing through intervening tissue that affects the EEG.

I don't have any good references for you, it's been decades since I worked in this area, but physiology texts will cover the cellular processes, and neurology/neurobiology texts will give you more. Later if you want an entry into the physics literature, I would try searching on things like action potential propagation, nerve current propagation, magnetoencephalogram, etc. Take a look in articles for references either to textbooks and review articles, or to early literature where they were figuring out the basics.

Don't make up your mind on accelerators until you look into this. It's pretty cool!

 

[Hootenanny]

Thanks a lot marcusl, I shall go and root around in the med school on library on Monday.

 

[marcusl]

You're welcome! If you wouldn't mind, update us on how it's going in a few weeks.