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

9. Muscle Tissue

Sliding Filament Theory and the Sacromere

Anatomy & Physiology

9. Muscle Tissue

Sliding Filament Theory and the Sacromere

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Multiple Choice

What is the role of tropomyosin in muscle contraction?

Tropomyosin forms cross-bridges with myosin heads during contraction.

Tropomyosin binds to calcium ions, initiating the contraction process.

Tropomyosin hydrolyzes ATP to provide energy for muscle contraction.

Tropomyosin blocks the myosin-binding sites on actin filaments, preventing contraction until calcium ions are present.

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Verified step by step guidance

Understand the structure of muscle fibers: Muscle fibers contain myofibrils, which are composed of repeating units called sarcomeres. Sarcomeres contain actin (thin filaments) and myosin (thick filaments) that interact during muscle contraction.

Identify the role of tropomyosin: Tropomyosin is a regulatory protein that is part of the thin filament structure. It is positioned along the actin filaments and plays a crucial role in regulating muscle contraction.

Explore the function of tropomyosin in muscle contraction: Tropomyosin covers the myosin-binding sites on actin filaments, preventing myosin heads from attaching to actin and forming cross-bridges. This blockage prevents muscle contraction in the absence of calcium ions.

Learn about the role of calcium ions: When a muscle cell is stimulated, calcium ions are released from the sarcoplasmic reticulum into the cytoplasm. Calcium ions bind to another regulatory protein called troponin, which causes a conformational change in tropomyosin.

Understand the process of contraction initiation: The binding of calcium ions to troponin causes tropomyosin to move away from the myosin-binding sites on actin. This exposure allows myosin heads to attach to actin, forming cross-bridges and initiating muscle contraction.