Why is buffering of urine important for preventing acidosis?

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.

Correct Answer: B

Rationale: The correct answer is B because faster, deeper respirations help to eliminate excess CO2, which reduces the concentration of H+ ions in the blood, thus increasing pH. This compensates for the change in [H+] and helps maintain pH balance. Slower, shallower respirations (choice C) would not effectively eliminate CO2, leading to a buildup of H+ ions and a decrease in pH. Slower, deeper respirations (choice D) would also not effectively eliminate CO2, and the depth of respiration alone does not directly impact pH regulation. Choice A is incorrect because the respiratory mechanism plays a crucial role in pH control through the elimination of CO2.

Correct Answer: A

Rationale: Step 1: Plasma contains various substances like water, electrolytes, hormones, and nutrients. Step 2: The input of these substances is mainly determined by factors like diet, metabolism, and hormonal regulation. Step 3: Therefore, the overall input of substances in plasma is not extensively controlled. Step 4: Choice A (TRUE) is correct because the input of substances in plasma is not highly regulated. Step 5: Choices B, C, and D are incorrect as they do not align with the fact that the input of substances in plasma is not tightly controlled.

Correct Answer: B

Rationale: The correct answer is B: FALSE. In a state of negative water balance, the body is losing more water than it is taking in. This will lead to dehydration and a decrease in total body water volume, not an increase. The other choices, A, C, and D, are incorrect as they do not accurately reflect the impact of negative water balance on body volume.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Na+ is the major cation of the ECF (extracellular fluid), not the ICF (intracellular fluid). K+ is the major cation of the ICF, not the major anion of the ECF. Therefore, the statement in the question is incorrect. Choice A is incorrect because it incorrectly states the information. Choices C and D are irrelevant as they do not provide any relevant response to the question.