Sunday medical term

edema
abnormal collection of fluid, usually causing swelling


I'm sure a lot of people know this word, but I'm putting it in here anyway because it lets me discuss the mechanisms of edema a little bit, and I thought it was interesting. I like this definition (from the anatomy book) better than the one from the medical terminology book, which was worded the other way around - something on the order of "swelling, usually caused by abnormal collection of fluid in the tissues". The excess fluid arises on a microscopic level, in the interstitium between the capillaries and the cells. Normally the capillaries take out the same volume of fluid that they bring in, keeping things in balance, but when things get out of whack the fluid builds up in the interstitial space and eventually becomes noticeable as swelling. One example the book gave was hypoalbuminemia - a lack of albumin, which is a protein, in the blood. The presence of the proteins in the capillaries - in some mysterious way that I don't entirely understand - draws water back in with them, so a lack of proteins means more water stays in the interstitium.

OK, the page is sort of swimming so I think that means it's my bedtime. Hope this makes a reasonable amount of sense!