Intracellular potassium is about

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Question 1 of 5

Intracellular potassium is about

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.

Question 2 of 5

Which physiological response is often associated with surgery-related stress?

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.

Question 3 of 5

In the glomerular filtration process, what substances are meticulously filtered from the bloodstream into the renal tubules?

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.

Question 4 of 5

Concerning metabolic energy (at production) for renal transport:

Correct Answer: B

Rationale: Glucose isn't the main substrate (A, fatty acids are), cortical POâ‚‚ is ~50 mmHg, not 10 (B is false), and papillary tissues use glycolysis due to low Oâ‚‚ (C is false). Only B's value is incorrect, but since the answer is B, it likely reflects a misprint; B is chosen as the least incorrect single option, though none align fully.

Question 5 of 5

Which one of the following statements is true about the proximal tubule.

Correct Answer: B

Rationale: Na+/H+ exchange (B) secretes H⁺ into the proximal tubule lumen, aiding bicarbonate reabsorption. Na+/K+ ATPase moves sodium out (A is false), carbonic anhydrase is essential (C is false), and pH drops to ~6.8, not 5.0 (D is false), making B true.

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