Which Statement Concerning the Countercurrent System Is INCORRECT

question 258

Multiple Choice

Which statement concerning the countercurrent system is INCORRECT?

• A) The loops of Henle of juxtamedullary nephrons are responsible for establishing a vertical osmotic gradient in the interstitial fluid of the renal medulla by countercurrent multiplication.
• B) The active NaCl pump of the ascending limb of Henle's limb can establish a 1,200 mosm/litre concentration difference between the ascending and descending limbs at any given horizontal level.
• C) By means of countercurrent exchange, the vasa recta preserve the vertical osmotic gradient while supplying blood to the medullary tissue.
• D) The collecting tubules of all nephrons utilize the driving force of the vertical osmotic gradient to accomplish variable H₂O reabsorption under the control of vasopressin, which governs their permeability.

---

Definitions:

Variable Expense

Costs or expenses that change in proportion to business activity.

Electric Bill

A monthly statement charging an individual or household for the consumption of electricity provided by a utility company.

Cappuccinos

A coffee drink made with equal parts espresso, steamed milk, and milk foam.

Textbooks

Books that are used as standard works for the study of a particular subject.