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

What is the primary function of the countercurrent mechanism in the nephron?

To filter blood plasma into the Bowman's capsule

To regulate blood pressure by releasing renin

To secrete waste products into the distal convoluted tubule

To concentrate urine by reabsorbing water and solutes

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Verified step by step guidance

Understand the structure of the nephron, which includes the Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.

Recognize that the countercurrent mechanism primarily occurs in the loop of Henle, which is a U-shaped structure in the nephron.

Identify the role of the loop of Henle in creating a concentration gradient in the medulla of the kidney, which is essential for water reabsorption.

Learn that the descending limb of the loop of Henle is permeable to water but not to solutes, allowing water to be reabsorbed into the surrounding medullary interstitium.

Understand that the ascending limb of the loop of Henle is impermeable to water but actively transports solutes (such as Na+ and Cl-) out of the tubular fluid, contributing to the concentration gradient that facilitates water reabsorption in the collecting duct, ultimately concentrating the urine.