The nurse is planning care for an older adult client who experienced a cerebrovascular accident several weeks ago. The client has expressive aphasia and often becomes frustrated with the nursing staff. Which intervention should the nurse implement?

Correct Answer: C

Rationale: For a client with expressive aphasia post-CVA, encouraging the use of picture charts is the most effective intervention. Expressive aphasia impairs the ability to speak or write, but comprehension may remain intact. Picture charts allow the client to communicate needs visually, reducing frustration and enhancing interaction with staff. Sign language requires learning and motor skills that may be compromised, slow speech aids comprehension but not expression, and simple questions don't address the communication barrier as directly as pictures do.

Correct Answer: C

Rationale: Antidiuretic hormone (ADH) regulates water reabsorption primarily in the medullary collecting duct. ADH increases the insertion of aquaporin-2 water channels into the apical membrane, allowing water to move from the tubular lumen into the hyperosmotic medullary interstitium, concentrating urine. The proximal tubule and Loop of Henle reabsorb water independently of ADH, and the distal tubule has minor ADH effects, making the medullary collecting duct the key site, thus C is correct.

Correct Answer: D

Rationale: A substance for GFR measurement, like inulin, must be freely filtered, not secreted (A) or reabsorbed (B) by tubules, and non-toxic (C) to ensure clearance equals GFR. It should not be metabolized (D), as metabolism alters its concentration, invalidating the measurement. Thus, ‘should be metabolized' is not a criterion, making D correct.

Correct Answer: B

Rationale: Sympathetic activity constricts both afferent and efferent arterioles, reducing renal blood flow and GFR. Lower GFR decreases the filtered Na⁺ load, but slower filtrate flow allows less Na⁺ reabsorption in the PCT, increasing Na⁺ delivery to the macula densa in the distal tubule. GFR doesn't increase (A), PCT reabsorption decreases (C), and filtered load drops (D), making B correct.

Correct Answer: B

Rationale: Carbonic acid ([H₂CO₃]) in blood is very low (~0.001 mM) and unstable, rapidly dissociating into CO₂ and H₂O, making direct measurement difficult. It's estimated via PCO₂ (0.03 × PCO₂ in Henderson-Hasselbalch). It remains effective in the bicarbonate buffer equation (C is false), and no replacement is needed (D), making B correct.