Today's physiology lecture reinforced the idea that my phys prof (Dr Hunter) is at least partially crazy. We were talking about reflex arcs and how they occur independent of the brain. The science - when your body notices that something really bad is going on that you need to get away from (ex: you're touching a hot stove burner), the pain receptors (in this case, thermal pain receptors) send a signal along an afferent pathway to your spinal cord, where the afferent nerve synapses with an interneuron (or more than one), which synapses with an efferent nerve that makes you jerk your hand away (ex: an excitatory interneuron sends a signal to your bicep to contract while an inhibitory interneuron sends a signal to your triceps to relax, so that your hand is pulled away from the heat source). The afferent nerve also sends a signal up to your brain to let it know what's going on (as in, wow, my hand was on a burner and that hurt) so that it can learn from your mistakes (don't put hand on burner, fool). Your brain had nothing to do with the reflex that pulled your hand away - if you didn't have a brain, your reflex would be the same (however, you do need your higher brain to perceive pain). Apparently in the olden days (pre-1990), they would illustrate this principle by taking a bullfrog, chopping its head off, and then dipping its toes in varying concentrations of sulfuric acid. But, Dr Hunter said, they can't do that anymore because people thought it was too cruel (surprise). Then Dr Hunter proceeded to point to a cage up front and said "this is what I would bring the frog in to class with...wait, I think I do have a frog." He reached in and slowly pulled out a high quality paper copy of a frog and proceeded to "perform" the entire experiment with it, including the chopping off of the head, the dipping of the toes in sulfuric acid, neutralizing the acid in between dips with sodium bicarbonate, and making the frog head talk to the class.
He also told us to test the "crossed extensor reflex" on one of our roommates when they're sleeping. This is the reflex that you use when you step on a nail or something else sharp - as soon as your body feels the pain, you pick up that foot and automatically support yourself with the other leg. He told us to go into our roommate's room when they're asleep and carefully move a hand into position without waking them and bite a finger. He said to watch out, because as they withdraw the bitten hand, their other hand will come across and punch you in the face. Cool. Emily better watch out... :)
Other cool physiology info recently learned:
-We talked about how our perception of reality is far from what the world is really like, since we lack the sensors for all sorts of energy (this we know - like how we can't perceive x-rays or microwaves or IR or magnetism, etc)...but he said that 1 in 20,000 people can detect magnetic fields. If you spin them around blindfolded, they'll always where north is.
-Ever wonder why many Japanese people can't tell the difference between 'r' and 'l'? It is because all people as infants can distinguish between and articulate the entire range of speech sounds (used in every language), but as we mature we lose the ability to distinguish between sounds not used in our native language(s). So Japanese people can totally lose the ability to tell 'r' from 'l'. You can look them in the face and say "la...ra...lake...rake...lack...rack..." all you want and they won't be able to distinguish the 'l's from 'r's.
I took Murphy for a walk in the park at the end of our street last night. He had a really good time. And then when Emily and I watched the Real World later that night, he sat in her lap and allowed her to hold his chicken stick for him. How generous of him. Matt called from Nashville last night - they'd drive for 10 hours yesterday, and today's drive to Indianapolis was to be much shorter. They were going to stop at Churchill Downs to watch a horserace on the way. The Phish concert is at 7, but they have to get there early to get good lawn seats. So all is going well on the great Phish roadtrip so far - I'll get another update tomorrow afternoon. I'm heading to the miniranch as soon as I get out of lab and pick up the dog tomorrow. Tonight I'm supposed to have dinner with Amanda. FUN! There is much catching up to be done. :)
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