Quick Physiology Lesson

Say, Mon, why all the talk about pee?

Basically the kidney filters the blood. If you replace that function with dialysis, you don't pee. Imagine not taking a leak. That's kind of a big deal, right? A lot of people aren't aware that folks who start dialysis just don't make any pee whatsoever. (Uncle Charlie never goes to the bathroom. What a freak!)

So what else does a kidney do?

Besides make you go to the head every time you have a beer, the kidney has many endocrine functions. Yep. It's the target organ for many of the bodies chemical signals. The pituitary makes anti-diuretic hormones that control water balance by directly controlling the H2O and K+ passing through the glomeruli. Aldosterone from the adrenal glands act on the kidney to control blood pressure. If the kidney does not function properly, the parathyroid gland becomes overactive and raises the blood calcium and phosphorus to dangerous levels, and thereby destroying bones, taxing the circulatory system, and driving your serum pH through the floor.

The kidney has two major endocrine hormones of it's own as well. Erythropoitin and renin. The former acts on the bone marrow to make red blood cells and the later sends the first in a cascade of signals in the maintenance of normal blood pressure.

So, just beyond filtering nitrogenous waste out of blood, it does a whole lotta important bidnezz.

FYI, dialysis only does a few of these things. It cannot replace the endocrine functions of that organ, therefore renal patients tend to be anemic and have sky high blood pressure. Even under medication it can be in the stroke producing neighborhood. No joke.

In Mark's case, high blood pressure contributed to a slightly enlarged left ventricle...which...get this... improves in 85% of the cases after renal graft. Huzzah.

So that is my cute little post about kidney physiology.

Thank you very much.

Monica Carmody
10th grade biology
Mrs. Smith's class