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

14. The Autonomic Nervous System

Sympathetic Nervous System

Anatomy & Physiology

14. The Autonomic Nervous System

Sympathetic Nervous System

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Multiple Choice

What effect does the sympathetic nervous system have on the diameter of most blood vessels?

It has no effect on blood vessel diameter.

It causes blood vessels to alternate between constriction and dilation.

It causes vasoconstriction, decreasing the diameter.

It causes vasodilation, increasing the diameter.

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Verified step by step guidance

Understand the role of the sympathetic nervous system: The sympathetic nervous system is part of the autonomic nervous system and is responsible for the 'fight or flight' response. It prepares the body to respond to stress or danger by altering various physiological functions.

Learn about blood vessel regulation: Blood vessel diameter is controlled by smooth muscle in the vessel walls. The sympathetic nervous system influences these muscles through neurotransmitters like norepinephrine.

Explore the mechanism of vasoconstriction: When the sympathetic nervous system is activated, norepinephrine binds to alpha-adrenergic receptors on the smooth muscle of most blood vessels. This causes the muscle to contract, leading to vasoconstriction (a decrease in vessel diameter).

Understand the physiological purpose: Vasoconstriction helps redirect blood flow to essential organs (like the heart and brain) during stress, while reducing blood flow to less critical areas (like the skin or digestive system).

Clarify exceptions: While the sympathetic nervous system generally causes vasoconstriction, it can cause vasodilation in certain vessels, such as those supplying skeletal muscles, through beta-adrenergic receptor activation. This ensures adequate oxygen delivery during physical activity.