Sunday, July 25, 2010

101 Interesting Things, part forty-five (a): Blood - An Overview

Leviticus 17:11 says, in part, "the life of the flesh is in the blood". This is one of those things where the Bible actually gets it right, but they really had no idea how right they were. It doesn't take any great leap of creativity to notice that draining the blood from an organism is, by and large, fatal to said organism: massive blood loss is so consistently fatal because blood does so goddamned much for us in the first place.

Blood carries oxygen, food, and water to living tissues; it carries waste to the kidneys, liver, and lungs; it maintains the police presence of the immune system and carries vital hormonal signals all throughout the body; it even has pressurized hydraulics and helps regulate body temperature, all within a narrow range of pH values (a tenth of a point, between 7.35 & 7.45). Your body is basically a sac for your blood, the universal fluid that ties every part and function together. They Might Be Giants explain it in broad strokes and easy language in The Bloodmobile:
In many ways, your life revolves around your blood: your bones make erythrocytes in their marrow, and your tendons (which technically aren't vascularized) hold your bones together in ways that (usually) don't impinge upon the flow of your circulatory system; your circulatory system, in turn, carries blood to the various organs you use to maintain the fuel supply within your blood, including the brain and heart with their minute-to-minute demand for oxygen; your digestive tract is a tube within a tube, busting up what you eat at the molecular level to harvest the aforementioned fuel before dispensing with the unnecessary bits; and your skin holds it all in and keeps unwelcome elements out.

Blood's very ubiquity made this an unusually research-intensive entry, and there's so much interesting stuff that I want to take it by parts. This weekend - and since I'm not spending all my time reading about blood, I'll actually have time to write about it, so it will actually be this weekend - I'll write about blood's role in respiration and homeostasis, ferrying oxygen and carbon dioxide hither & yon, and regulating pH levels & body temperature. Next Wednesday, I'll write about the immune system, which I would normally give its very own entry except for the fact that it all kind of takes place within the blood. And the following weekend, I'll talk about blood technologies and diseases, because they are also fascinating. Stay tuned!


Atheist MC said...

Bloody excellent. I can't wait for the follow up.

D said...

You mean the part with actual content and stuff? Heh. :) Thanks for the comment!