Which may cause hyperkalemia?

Choice A reason: This is incorrect because respiratory alkalosis is a condition where the blood pH is higher than the normal range of 7.35 to 7.45, due to hyperventilation, which lowers the carbon dioxide in the blood. Severe diarrhea does not cause hyperventilation, but rather dehydration and electrolyte imbalance.

Choice B reason: This is incorrect because metabolic alkalosis is a condition where the blood pH is higher than the normal range of 7.35 to 7.45, due to a loss of acids or an excess of bases in the body. Severe diarrhea does not cause a loss of acids or an excess of bases, but rather a loss of fluids and bicarbonate, which is a base that buffers the acids in the blood.

Choice C reason: This is correct because metabolic acidosis is a condition where the blood pH is lower than the normal range of 7.35 to 7.45, due to an excess of acids or a loss of bases in the body. Severe diarrhea causes a loss of fluids and bicarbonate, which is a base that buffers the acids in the blood. This leads to an accumulation of acids and a decrease in pH.

Choice D reason: This is incorrect because respiratory acidosis is a condition where the blood pH is lower than the normal range of 7.35 to 7.45, due to impaired gas exchange or hypoventilation, which causes carbon dioxide to accumulate in the blood. Severe diarrhea does not affect the respiratory system directly, but rather the metabolic system.

Choice A reason: This is incorrect because the adrenal gland is not involved in the thirst mechanism. The adrenal gland is responsible for producing hormones such as cortisol, aldosterone, and adrenaline, which regulate stress response, blood pressure, and metabolism.

Choice B reason: This is incorrect because the cerebral cortex is not involved in the thirst mechanism. The cerebral cortex is the outer layer of the brain that is responsible for higher cognitive functions such as memory, language, and reasoning.

Choice C reason: This is incorrect because the pituitary gland is not directly involved in the thirst mechanism. The pituitary gland is a small gland at the base of the brain that produces hormones that control growth, reproduction, and metabolism. However, the pituitary gland does secrete antidiuretic hormone (ADH), which is regulated by the hypothalamus and affects water balance in the body.

Choice D reason: This is correct because the hypothalamus is the location of the thirst mechanism. The hypothalamus is a part of the brain that regulates many bodily functions such as temperature, appetite, sleep, and emotions. The hypothalamus also monitors the blood osmolarity and triggers the sensation of thirst when the blood is too concentrated.