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

4. Tissues & Histology

Introduction to Muscle Tissue

Anatomy & Physiology

4. Tissues & Histology

Introduction to Muscle Tissue

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Multiple Choice

Which of the following is a characteristic of both type IIa and type IIx fast twitch muscle fibers?

They have high resistance to fatigue

They primarily use aerobic metabolism

They contract rapidly

They contain large amounts of myoglobin

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Verified step by step guidance

Understand the characteristics of fast-twitch muscle fibers: Type IIa and Type IIx are both fast-twitch fibers, meaning they are designed for quick, powerful contractions. They differ in their metabolic properties and fatigue resistance.

Review the contraction speed of fast-twitch fibers: Both Type IIa and Type IIx fibers contract rapidly compared to slow-twitch fibers (Type I). This rapid contraction is a defining feature of fast-twitch fibers.

Analyze fatigue resistance: Type IIa fibers have moderate resistance to fatigue due to their ability to use both aerobic and anaerobic metabolism, while Type IIx fibers fatigue quickly because they primarily rely on anaerobic metabolism.

Examine metabolic pathways: Type IIa fibers primarily use aerobic metabolism but can also utilize anaerobic pathways, whereas Type IIx fibers rely almost entirely on anaerobic metabolism for energy production.

Evaluate myoglobin content: Type IIa fibers contain moderate amounts of myoglobin, aiding in aerobic metabolism, while Type IIx fibers have lower myoglobin levels, reflecting their reliance on anaerobic processes.