What term best describes a pH of 7.3 in the blood?

Correct Answer: B

Rationale: The correct answer is B: acidaemia. A pH of 7.3 in the blood indicates an acidic environment, as it is below the normal range of 7.35-7.45. Acidaemia specifically refers to the presence of excess acid in the blood. Choice A, acidosis, refers to a systemic condition of excess acid in the body, not just in the blood. Choice C, alkalosis, is the opposite of acidosis and describes a condition of excess base in the body. Choice D, alkalaemia, is not a recognized term in medical literature and is not used to describe a pH of 7.3 in the blood.

Correct Answer: A

Rationale: The correct answer is A: phosphate. Phosphate is a potent urinary buffer as it helps maintain the acid-base balance in the body by accepting or donating hydrogen ions in the urine. Phosphate plays a crucial role in regulating the pH of urine, making it an effective urinary buffer. Summary: - Phosphate is a potent urinary buffer as it helps regulate the pH of urine. - Haemoglobin is not a urinary buffer, it mainly functions in oxygen transport. - Bicarbonate/carbonic acid primarily acts as an extracellular buffer in the blood, not in the urine. - Proteins do have buffering capacity, but they are not specific to urinary buffering.

Correct Answer: C

Rationale: Rationale for Correct Answer (C): 1. Chemical buffers work quickly but may not be sufficient for rapid or large pH changes. 2. Kidneys can regulate acid-base balance by adjusting excretion of H+ and HCO3-. 3. Kidneys can respond immediately to maintain acid-base homeostasis. 4. Therefore, kidneys participate in acid-base balance to provide a rapid and effective response. Summary of Incorrect Choices: A. Incorrect because chemical buffers can act throughout the body, including the ECF around the kidneys. B. Incorrect because chemical buffers can buffer against various pH changes, not just those from increased HCO3-. D. Incorrect because chemical buffers can also bind to other ions, not just H+, and kidneys do not remove H+ entirely from the body.

Correct Answer: A

Rationale: The correct answer is A: uncompensated metabolic acidosis. The ratio of [HCO3-] / [CO2] is typically around 20/1 in the blood (normal range). In this case, the ratio is 40/1, indicating an increase in [HCO3-] relative to [CO2]. This suggests metabolic alkalosis. However, if the ratio is inverted (as in this case), it indicates compensation for a primary respiratory alkalosis. This leads to a primary metabolic acidosis. Therefore, the correct interpretation is uncompensated metabolic acidosis. Choices B, C, and D are incorrect as they do not consider the specific relationship between [HCO3-] and [CO2].

Correct Answer: B

Rationale: Rationale: The correct answer is B because the serum anionic gap is a valuable tool in diagnosing the cause of metabolic acidosis. By calculating the anion gap (serum sodium - (serum chloride + serum bicarbonate)), clinicians can identify unmeasured anions such as lactate or ketones, which are often elevated in metabolic acidosis. This information helps differentiate between various causes of metabolic acidosis, such as lactic acidosis or ketoacidosis. Summary: A: Incorrect. The serum anionic gap is not typically used to diagnose the cause of metabolic alkalosis. C: Incorrect. The serum anionic gap is not typically used to diagnose the cause of respiratory alkalosis. D: Incorrect. The serum anionic gap is not typically used to diagnose the cause of respiratory acidosis.