Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

25. The Urinary System

Renal Physiology: Overview

Anatomy & Physiology

25. The Urinary System

Renal Physiology: Overview

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Multiple Choice

In the ascending limb of the nephron loop, which of the following occurs?

Water is passively reabsorbed

Urea is actively reabsorbed

Glucose is secreted into the filtrate

Sodium and chloride ions are actively reabsorbed

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Verified step by step guidance

Understand the structure and function of the nephron loop (loop of Henle). The nephron loop is divided into two segments: the descending limb and the ascending limb. The descending limb is permeable to water, while the ascending limb is impermeable to water but actively transports ions.

Recognize the role of the ascending limb in reabsorption. The ascending limb is responsible for actively reabsorbing sodium (Na⁺) and chloride (Cl⁻) ions into the surrounding interstitial fluid, which helps create the concentration gradient necessary for water reabsorption in other parts of the nephron.

Clarify why water is not passively reabsorbed in the ascending limb. The ascending limb is impermeable to water, meaning water cannot move across its walls, even passively. This is a key distinction from the descending limb.

Explain why urea and glucose are not involved in the processes of the ascending limb. Urea is primarily reabsorbed in the collecting duct, and glucose is reabsorbed in the proximal convoluted tubule, not secreted into the filtrate in the nephron loop.

Conclude that the correct process occurring in the ascending limb is the active reabsorption of sodium and chloride ions. This active transport is essential for maintaining the osmotic gradient in the kidney, which is critical for water balance and urine concentration.