Which statement accurately describes buffering activities 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: C

Rationale: Step-by-step rationale: 1. Vomiting leads to loss of fluids and electrolytes, causing dehydration. 2. Loss of stomach acid (HCl) during vomiting can result in metabolic alkalosis. 3. Dehydration leads to increased concentration of HCO3- in the blood, causing metabolic acidosis. 4. Therefore, vomiting can lead to dehydration and metabolic acidosis (Choice C). Summary: - Choice A is incorrect as vomiting leads to loss of H+ ions, not abnormal buildup. - Choice B is incorrect as vomiting does not lead to a decrease in HCO3-. - Choice D is incorrect as vomiting typically leads to metabolic acidosis, not alkalosis.

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.