When a patient has PH changes first line of defense will be the physiological buffer system, if it's not enough the chemical buffer system will take place?

Correct Answer: B

Rationale: The statement is incorrect. Chemical buffers (bicarbonate, phosphate, proteins) are the first line of defense, instantly neutralizing pH changes. Physiological responses (respiratory CO₂ adjustment, renal H⁺/HCO₃⁻ regulation) follow if buffers are insufficient. The terms are reversed here, making B (False) correct.

Correct Answer: B

Rationale: Tubular secretion actively transports substances (e.g., H⁺, K⁺, drugs) from peritubular capillaries into renal tubules (B), aiding waste elimination and pH balance. Reabsorption (A) retrieves substances, filtration (C) is glomerular, and blood pressure control (D) is indirect, making B the correct role.

Correct Answer: D

Rationale: Sympathetic stimulation (A) constricts the afferent arteriole, reducing GFR; obstruction (B) increases capsular pressure, lowering GFR; and efferent vasodilation (C) decreases glomerular pressure, reducing GFR. None increase GFR—sympathetic effects lower it, obstruction opposes filtration, and efferent dilation reduces driving force—making D (none are correct) the answer.

Correct Answer: C

Rationale: Within an hour, buffers (A), lungs (B), and hemoglobin (D) act, but kidneys can't fully eliminate nonvolatile acids or regenerate all bicarbonate (C) that fast—renal response takes hours to days. C is the exception, making it the answer.

Correct Answer: C

Rationale: Chloride follows sodium's active reabsorption in the PCT due to electrical attraction (C), maintaining charge balance. It's not actively transported (A), tied to calcium (B), or driven solely by osmosis (D), making C the mechanism.