37 year old man with blood glucose of 900 mg/dl and TMAX of 380 mg/min. What is the expected amount of glucose in the urine?

Correct Answer: B

Rationale: To determine glucose in the urine, first calculate the glucose filtration rate: Blood glucose (900 mg/dl) × GFR (assume normal 125 ml/min) = 900 mg/dl × 1.25 dl/min = 1125 mg/min. The tubular maximum (Tmax) for glucose reabsorption is 380 mg/min. Any glucose filtered beyond Tmax is excreted: 1125 - 380 = 745 mg/min. This reflects glucosuria due to exceeding reabsorption capacity, common in hyperglycemia, making B correct.

Correct Answer: B

Rationale: Intracellular potassium (K⁺) concentration is approximately 150 mM, maintained by the Na⁺/K⁺-ATPase pump, which exchanges Na⁺ out for K⁺ in, creating a high K⁺ gradient inside cells (e.g., tubular cells). Extracellular K⁺ is 3.5-5 mM (C), 125 mM is close but typical for some texts (A), and 100 mM is too low, making B the standard value.

Correct Answer: A

Rationale: As hydrogen ion concentration ([H⁺]) increases, pH decreases per pH = -log[H⁺], indicating acidosis (pH < 7.35). Conversely, decreased [H⁺] raises pH, causing alkalosis. Option A correctly pairs rising [H⁺] with falling pH and acidosis, while B, C, and D misalign definitions, making A correct.

Correct Answer: D

Rationale: Surgery-related stress activates the hypothalamic-pituitary-adrenal axis, releasing cortisol and aldosterone, causing sodium and water retention (D) to maintain blood volume and pressure. Bronchial constriction (A) isn't typical, cortisol increases (not decreases, B), and vasodilation (C) opposes stress vasoconstriction, making D the correct response.

Correct Answer: B

Rationale: Glomerular filtration filters water and electrolytes (e.g., Na⁺, Cl⁻) (B) from blood into the tubules, forming filtrate, while retaining large molecules like proteins and cells. Oxygen/CO₂ (A) are respiratory, proteins (C) are blocked, and blood cells (D) stay in capillaries, making B correct.