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

2. Cell Chemistry & Cell Components

Concentration Gradients and Diffusion

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Concentration Gradients and Diffusion

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Multiple Choice

Why is there a concentration gradient of NaCl in the medulla of the kidney?

To increase the production of red blood cells.

To enhance the filtration rate of the glomerulus.

To facilitate the reabsorption of water in the collecting ducts.

To promote the secretion of hormones from the adrenal cortex.

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Verified step by step guidance

Understand the role of the kidney's medulla: The medulla is the innermost part of the kidney and plays a crucial role in concentrating urine and maintaining water balance in the body.

Recognize the function of NaCl concentration gradient: The concentration gradient of sodium chloride (NaCl) in the medulla is essential for the kidney's ability to reabsorb water from the filtrate in the collecting ducts.

Explain the countercurrent multiplier system: The loop of Henle, a part of the nephron, creates a concentration gradient through a process called the countercurrent multiplier system, which involves the active transport of NaCl out of the ascending limb.

Relate the gradient to water reabsorption: The high concentration of NaCl in the medulla creates an osmotic gradient that allows water to be reabsorbed from the collecting ducts back into the bloodstream, concentrating the urine.

Connect to the physiological purpose: This mechanism is crucial for the body's ability to conserve water, especially in conditions of dehydration, and is not related to red blood cell production, glomerular filtration rate, or hormone secretion from the adrenal cortex.