Renal Acid Base Regulation

The kidneys help to regulate the blood pH by excreting H+ in the urine and by reabsorbing bicarbonate. The H+ enters the filtrate in two ways: by filtration through the glomeruli and by secretion into the tubules. Most of the H+ secretion occurs across the wall of the proximal tubule in exchange for the reabsorption of Na+. This exchange is performed by a transport carrier described as "antiport," because it moves the Na+ and H+ in opposite directions (see chapter 6).

Since the kidneys normally reabsorb almost all of the filtered bicarbonate and excrete H+, normal urine contains little bicarbonate and is slightly acidic (with a pH range between 5 and 7). The mechanisms involved in acidification of the urine and reabsorption of bicarbonate are summarized in figure 17.28.

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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