Leave the Lights On reminded me of the tenuous wonder of the beginning of life in the post How Human Fertilization Takes Place. And then the post hearkened back to my high school biology class where I originally learned what "haploid" and "diploid" meant. Then forgot. But it also hearkened back to a book called "Fearfully and Wonderfully Made" by Dr. Paul Brand and Phillip Yancy. And when I hearkened back to that book, I hearkened back to the chapter on neurons*.
The authors discuss a very strange, yet amazing aspect of our nervous system. And that is the hierarchy and delegation of tasks in our body's nervous system. Your brain controls many aspects of movement. But not all. There are other "wills" or "minds" located throughout your body.
You can consciously tell yourself, "Hey! Chump! Pick up that spoon and pack down that entire pint of Ben and Jerry's Chubby Hubby ice cream." So, at your brain's direction, you stroll to the freezer and enjoy the peanut buttery-chocolatey-pretzely-malty bliss. That is one level of the hierarchy of your nervous system: direct commands from your brain to your body.
Midway through the pint, your stomach might say, "Hey! Buddy! I'm a bit crammed down here. Why don't you step away from the ice cream, just put the spoon down. That's it. Slowly now." But then your mind says, "Nuh uh! Deal with it pal! Because I want more and I'm making this spoon dig out that huge chocolate chunk and shove it down your maw!" And then shoulder, arm, and hand and fingers obey the brain. Much to your stomach's dismay.**
But your body has other control centers, apart from your brain. Let's say that on the way to the freezer, there's a rusty nail poking up through the floor board. And let's say you step on the rusty nail. Your foot, by it's own control and volition, apart from your brain, instantly registers the pain and immediately withdraws. Completely on its own accord. The pain signal was not sent to your brain, processed, then a signal sent from the brain to the foot instructing it to withdraw. That would take way too long. And this happens with not only your foot. In a sense, there's a "mind" or "will" in your hand too. Because as you were hopping up and down, hollering in agony from stepping on the nail, you tried to steady yourself by placing your hand on the stove. Which was still on. So now what happens? A pain signal sent from your hand up to the brain, processed, then a signal sent back to the hand to withdraw? Nope. The hand controls itself (!) and withdraws immediately. Soon after, the brain might signal your hand to punch the counter in anger and for how stupid you feel. But the initial reflex occurred independently.
Yet both the foot and the hand have their own "minds" or "will" located in just a few nerves attached to a few muscles. To a significant degree, you are not controlled by your brain. You are out of your mind. But, as Dr. Brand shows, the will of one "mind" can over-ride the will of another. If you're trying to escape a burning airplane, your head can tell you to run across broken glass, jagged metal, burning shards in order to save your life; overriding the will of your feet that would otherwise recoil in a normal situation to such stimuli.
You could argue that each cell within the body is autonomous and has a mind of its own. It receives instructions and participates in various feedback loops, cooperates with other cells, but at any time could decide to act on its own, depending on the stimuli that it receives.
I consider "Fearfully and Wonderfully Made" to be essential reading if you're fascinated by the workings of the human body. Do yourself a favor, grab a pint of Chubby Hubby and read the book cover to cover. You'll not be disappointed (in either the book or the ice cream).
And if you're not fascinated by the workings of the human body, well... you're out of your mind!!!
The Fine Print
*I realize that by this time you're probably hearkening back your hand ready to slap me upside the head if I use the word "hearken" just one more time. I know. It's just that some words are so delightful, and under-used that I just have to give them some love from time to time. I promise I won't use the word "hearken" any more in this blog. Nay, more than promise. I vow to not say "hearken" again. Yup. You can count on me that "hearken" might as well not even exist, because my keyboard will not type the letters H E A R K E N in that order anymore. Five Bonus Points if you come up with other delightful but neglected words.
**Later, the stomach might get it's revenge with it's own will and revolt. But in the meantime, the brain is totally in control. Oh yeah! Now dig out that big ol' pretzel. Oh yeah! So much crunchy malty goodness in that bite!!
1/23/08 Update: I'm giving "Leave the Lights On" 10 bonus points for some Paint graphics. Not because the graphics are spectacular, but because they are exactly what I would've done and I'm glad the bar wasn't set too high. ;)
1/23/08 Update: Boris corrected me in the comments that the withdrawl reflex originates in the spine. Much thanks! 10 bonus points to him. Now if only Chubby Hubby could be purchased with BPs...