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

1. Introduction to Anatomy & Physiology

Introduction to Organ Systems

Anatomy & Physiology

1. Introduction to Anatomy & Physiology

Introduction to Organ Systems

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Multiple Choice

Which vessel layer has a direct role in vasoconstriction?

Tunica externa

Tunica intima

Endothelium

Tunica media

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Verified step by step guidance

Understand the structure of blood vessel walls: Blood vessels have three layers—tunica externa (outer layer), tunica media (middle layer), and tunica intima (inner layer). Each layer has specific functions.

Focus on the tunica media: The tunica media is primarily composed of smooth muscle cells and elastic fibers. This layer is responsible for regulating the diameter of the blood vessel.

Learn the mechanism of vasoconstriction: Vasoconstriction is the narrowing of blood vessels, which occurs when the smooth muscle in the tunica media contracts. This process reduces blood flow and increases blood pressure.

Differentiate the roles of other layers: The tunica externa provides structural support and protection, while the tunica intima (including the endothelium) is involved in reducing friction for blood flow and regulating vascular functions like clotting and permeability.

Conclude that the tunica media has a direct role in vasoconstriction due to its smooth muscle composition, which allows it to contract and control vessel diameter.