Which of these actions would NOT be triggered by a drop in arterial blood pressure?

Correct Answer: C

Rationale: The correct answer is C because an increase in sodium reabsorption would be triggered by a drop in arterial blood pressure, not a decrease. When arterial blood pressure drops, the body aims to retain sodium and water to increase blood volume and pressure. Choices A, B, and D are incorrect as they are all actions that would be triggered by a drop in arterial blood pressure. A decrease in glomerular filtration rate (GFR) helps conserve fluids and maintain blood pressure, release of aldosterone promotes sodium and water retention, and a decrease in chloride excretion also helps in retaining fluids. Therefore, an increase in sodium reabsorption is the action NOT triggered by a drop in arterial blood pressure.

Correct Answer: D

Rationale: The correct answer is D because when the rate of CO removal by the lungs is less than the rate of CO production by the tissues, more CO builds up in the body. This excess CO leads to increased generation of H+ ions due to the breakdown of CO into H+ ions and carbon. This acidic environment from the increased H+ ions can disrupt the body's pH balance. Choice A is incorrect because the rate of protein catabolism and anabolism does not directly impact the generation of H+ from CO. Choice B is also incorrect because the speed of protein breakdown and synthesis does not affect the generation of H+ from CO. Choice C is incorrect because the rate of CO removal by the lungs being higher than CO production does not lead to an increase in H+ generation.

Correct Answer: B

Rationale: The correct answer is B: Chemical buffer systems respond to changes in acid or base levels. This is because chemical buffer systems work by absorbing or releasing H+ ions to maintain a stable pH in the body. They act immediately to prevent drastic changes in pH levels. A is incorrect because chemical buffer systems act almost instantaneously, not in one to three minutes. C is incorrect because chemical buffer systems do not directly promote H+ excretion by the kidneys; that is the role of the renal system. D is incorrect because chemical buffer systems do not directly stimulate the respiratory center; that is the role of the respiratory system.

Correct Answer: A

Rationale: Step 1: The respiratory system can react to changes in pH quickly due to its ability to modify the rate and depth of breathing. Step 2: By increasing the rate and depth of breathing, excess CO2 is expelled, reducing H+ concentration and restoring pH balance. Step 3: This rapid response allows the respiratory system to buffer against pH changes within seconds. Step 4: Choice A is correct as it accurately describes the buffering activities of the respiratory system. Summary: Choice B is incorrect because an increase in pH would lead to a decrease in H+ concentration, triggering an increase in the depth and rate of breathing. Choice C is incorrect as the respiratory system can buffer against both increases and decreases in arterial [H+]. Choice D is incorrect as the respiratory system can counteract changes in pH from both respiratory and nonrespiratory causes.

Correct Answer: D

Rationale: Buffering of urine is important to prevent acidosis because if urine becomes too acidic, it prevents tubular secretion of H+ ions, limiting the renal buffering capacity. This helps maintain the body's acid-base balance. Choices A, B, and C are incorrect because they do not directly relate to the role of buffering urine in preventing acidosis. Choice A is incorrect because bicarbonate secretion is a mechanism to counteract acidosis, not a reason for buffering urine. Choice B is incorrect as acidic urine does not directly inhibit the micturition reflex. Choice C is incorrect because acidic urine does not typically damage the urinary bladder.