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 Heart2h 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

17. The Blood

Platelets: Hemostasis

Anatomy & Physiology

17. The Blood

Platelets: Hemostasis

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Multiple Choice

Which of the following is true regarding the extrinsic pathway of blood clotting?

The extrinsic pathway is independent of procoagulants.

The extrinsic pathway does not involve calcium ions.

The extrinsic pathway is slower than the intrinsic pathway of blood clotting.

The extrinsic pathway is triggered by tissue factor.

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Verified step by step guidance

Understand the context: Blood clotting involves a series of complex processes that prevent excessive bleeding when a blood vessel is injured. There are two main pathways: the intrinsic and extrinsic pathways, both leading to the formation of a blood clot.

Identify the role of the extrinsic pathway: The extrinsic pathway is initiated by external trauma that causes blood to escape from the vascular system. It is known for being a rapid response to injury.

Recognize the key components: The extrinsic pathway is triggered by the release of tissue factor (TF), also known as factor III, from damaged tissues. This is a crucial step that distinguishes it from the intrinsic pathway.

Clarify the involvement of calcium ions: Calcium ions (Ca²⁺) are essential for various steps in the blood clotting process, including the extrinsic pathway. They act as cofactors in the activation of several clotting factors.

Compare the speed of pathways: The extrinsic pathway is generally faster than the intrinsic pathway because it involves fewer steps and is directly activated by tissue factor, leading to a quicker formation of the clot.