Transcripts
DR. BRANDT:
If we look at a more magnified view, we see renal arteries branching and branching to smaller and smaller vessels until they get to this large ball of blood vessels, capillaries, called the glomerulus.
And this is really where the real work of the kidneys occurs. This ball of capillaries is where the blood is filtered. It's a membrane made up of two cell layers. In the space between the glomerular capillaries and the outer wall, urine (or what we might call proto-urine) is formed. The urine then passes through a number of tubules, and those tubules remove about 99 percent of the water and salts that are filtered initially by the glomerulus and push them back into the blood system. And then the final urine, which is made up of the little excess water we have each day and waste products, passes down into the collecting tubules and down to the bladder.
We will talk a little bit later about the importance of these small blood vessels down here, because these blood vessels that line the tubules are very susceptible to injuries, especially low oxygen tensions in the blood.
