Where is the Macula Densa located & what is its function?

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Renal System Multiple Choice Questions Questions

Question 1 of 5

Where is the Macula Densa located & what is its function?

Correct Answer: B

Rationale: The macula densa is a group of specialized cells located in the distal tubule, part of the juxtaglomerular apparatus (JGA), where the tubule contacts the afferent arteriole of the glomerulus. Its function is to act as chemoreceptors or osmoreceptors, sensing changes in sodium chloride concentration or osmolarity of the tubular fluid. These changes trigger signals that stimulate juxtaglomerular cells to secrete renin, regulating blood pressure and glomerular filtration rate (GFR). This specific location and role distinguish it from the other options, making B correct.

Question 2 of 5

The glucose started to appear in the urine before the transport maximum is reached because?

Correct Answer: A

Rationale: Glucose appears in urine before the overall Tmax (e.g., 375 mg/min) is reached because nephrons have varying Tmax values (splay). Some nephrons saturate earlier, spilling glucose while others still reabsorb, reflecting heterogeneity in reabsorption capacity. Complete reabsorption (B) occurs below Tmax, and tubular damage (D) isn't implied, making A correct.

Question 3 of 5

The absorption of Na⁺ in ascending loop of Henle:

Correct Answer: D

Rationale: In the ascending Loop of Henle, Na⁺ reabsorption varies: the thin ascending limb reabsorbs Na⁺ and Cl⁻ passively due to concentration gradients, while the thick ascending limb uses active transport via the Na⁺/K⁺/2Cl⁻ cotransporter, diluting the filtrate. This dual mechanism distinguishes it from all passive (A) or all active (B), making D correct.

Question 4 of 5

Which of the following laboratory results below indicates compensated metabolic alkalosis?

Correct Answer: D

Rationale: Compensated metabolic alkalosis involves high HCO₃⁻ (e.g., from vomiting) raising pH, with respiratory compensation increasing PCO₂ via hypoventilation to normalize pH. High PCO₂, high HCO₃⁻, and high (near-normal) pH (D) reflect this. Low PCO₂ (A, B) suggests respiratory alkalosis, and low pH (C) indicates acidosis, making D correct.

Question 5 of 5

A nursing department in an acute care setting decides to redesign its nursing practice based on a theoretical framework. The feedback from patients, families, and staff reflects that caring is a key element. Which theorist best supports this concept?

Correct Answer: D

Rationale: Jean Watson's theory of human caring emphasizes caring as the essence of nursing, focusing on holistic, patient-centered relationships, aligning with feedback valuing caring. Erikson (A) addresses development, Maslow (B) needs hierarchy, and Rogers (C) client-centered therapy, but Watson (D) directly supports caring as a framework.

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