When the body is in acidosis, what ion does the kidney excrete more of?

In acidosis, the body experiences an excess of hydrogen ions (H+) in the bloodstream, leading to a lower pH. The kidneys play a crucial role in maintaining acid-base balance in the body. When the body is in a state of acidosis, the kidneys respond by increasing the excretion of hydrogen ions to help restore normal pH levels. This increased excretion of H+ ions helps mitigate the effects of the excess acidity in the blood.

Moreover, by excreting more H+ ions, the kidneys also enhance the reabsorption of bicarbonate (HCO3-) in an effort to buffer the excess acidity. This response is part of the renal compensation mechanism for acidosis.

The other ions mentioned do not have the same direct relationship with the body's attempt to correct acidosis as H+ ions do. Sodium (Na+) and chloride (Cl-) ions are not specifically adjusted in response to acid-base imbalances, and the excretion of bicarbonate would actually exacerbate acidosis rather than correct it. Thus, the excretion of H+ ions is a key response of the kidneys during acidosis, making this the correct response.