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

19. The Blood Vessels

Capillaries

Anatomy & Physiology

19. The Blood Vessels

Capillaries

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Problem 7

Textbook Question

The local control of blood flow due to the action of precapillary sphincters is:
(a) Vasomotion
(b) Autoregulation
(c) Selective resistance
(d) Turbulence

Verified step by step guidance

Understand the role of precapillary sphincters: These are small rings of smooth muscle located at the entrance of capillary beds. They regulate blood flow by contracting or relaxing, controlling the amount of blood entering the capillaries.

Define the term 'local control of blood flow': Local control refers to the ability of tissues to regulate their own blood supply based on their metabolic needs, without relying on systemic signals like hormones or neural input.

Review the concept of autoregulation: Autoregulation is a mechanism by which blood vessels adjust their diameter in response to changes in local conditions, such as oxygen levels, carbon dioxide levels, or pH, ensuring adequate blood flow to meet tissue demands.

Compare the options provided: (a) Vasomotion refers to the rhythmic contraction and relaxation of precapillary sphincters, (b) Autoregulation involves broader mechanisms of local blood flow control, (c) Selective resistance is not a standard term in physiology, and (d) Turbulence refers to chaotic blood flow, which is unrelated to precapillary sphincter function.

Conclude that the correct term for the local control of blood flow due to precapillary sphincter action is 'vasomotion,' as it specifically describes the rhythmic adjustments made by these sphincters to regulate blood flow locally.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Precapillary Sphincters

Precapillary sphincters are small bands of smooth muscle located at the junction of arterioles and capillaries. They regulate blood flow into capillary beds by contracting or relaxing, thus controlling the amount of blood that enters a specific tissue area. This mechanism is crucial for maintaining tissue perfusion and responding to local metabolic needs.

Autoregulation

Autoregulation refers to the ability of blood vessels to maintain a relatively constant blood flow despite changes in perfusion pressure. This process is vital for organs like the brain and kidneys, allowing them to function optimally under varying systemic blood pressures. It involves local factors that influence vascular tone and resistance.

Vasomotion

Vasomotion is the rhythmic contraction and relaxation of blood vessels, particularly arterioles, which leads to fluctuations in blood flow. This process is influenced by various factors, including local metabolic activity and neural signals, and plays a role in regulating blood distribution to different tissues based on their immediate needs.

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