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

The Nephron

Anatomy & Physiology

25. The Urinary System

The Nephron

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Multiple Choice

In which part of the nephron loop is water primarily reabsorbed?

Proximal convoluted tubule

Distal convoluted tubule

Ascending limb

Descending limb

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Verified step by step guidance

Understand the structure of the nephron, which is the functional unit of the kidney. It consists of several parts: the proximal convoluted tubule, the loop of Henle (which includes the descending and ascending limbs), the distal convoluted tubule, and the collecting duct.

Recognize the role of each part of the nephron in the process of urine formation. The proximal convoluted tubule is primarily responsible for the reabsorption of nutrients, ions, and water.

Focus on the loop of Henle, which is divided into two limbs: the descending limb and the ascending limb. Each limb has distinct functions in the reabsorption process.

Identify the descending limb of the loop of Henle as the segment where water is primarily reabsorbed. This occurs because the descending limb is permeable to water but not to solutes, allowing water to move out of the nephron by osmosis into the surrounding hypertonic medullary interstitium.

Contrast this with the ascending limb, which is impermeable to water but actively transports ions out of the nephron, contributing to the concentration gradient in the medulla that facilitates water reabsorption in the descending limb.