A client is hospitalized after experiencing a myocardial infarction (MI). To reduce cardiac workload, which intervention should the nurse include in the client's plan of care?

Correct Answer: C

Rationale: Providing a bedside commode reduces cardiac workload in a client post-myocardial infarction (MI) by minimizing physical exertion. After an MI, the heart's oxygen demand must be kept low to prevent further damage, and activities like walking to the bathroom increase energy expenditure and strain. Using a commode allows the client to toilet without ambulating, conserving energy. Active exercises or hallway ambulation increase oxygen demand, while side-lying positioning, though helpful for comfort, doesn't directly address exertion as effectively as the commode.

Correct Answer: B

Rationale: Tubular secretion is the selective transfer of substances, such as hydrogen ions (H⁺), potassium (K⁺), and organic compounds, from the peritubular capillaries (blood) into the tubular lumen (urine). This process, occurring mainly in the proximal and distal convoluted tubules, helps eliminate waste and regulate blood pH and ion levels. It differs from reabsorption (A), glomerular filtration (C), and water reabsorption (D), making B the correct definition.

Correct Answer: C

Rationale: About 20% of the plasma entering the glomeruli via the afferent arteriole is filtered into the glomerular capsule, known as the filtration fraction. This is calculated as GFR (125 ml/min) divided by renal plasma flow (625 ml/min), equaling 0.2 or 20%. The remaining 80% exits via the efferent arteriole, making C correct, as 1%, 99%, and 15% do not reflect this physiology.

Correct Answer: C

Rationale: The thin descending limb of the Loop of Henle is highly permeable to water due to aquaporin-1 channels, allowing water to exit into the hyperosmotic medullary interstitium, concentrating the filtrate. The thick ascending limb is impermeable to water, actively reabsorbing Na⁺ and Cl⁻, and the thin ascending limb has limited water permeability, making C correct.

Correct Answer: B

Rationale: Most human enzymes function optimally at a physiological pH of 7.4, close to blood pH (7.35-7.45), where their active sites maintain proper conformation for catalysis. A pH of 7.8 (A) is slightly alkaline, 6.8 (C) is too acidic for most, and 2 (D) suits gastric enzymes like pepsin, not the majority, making B correct.