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

Which of the following statements regarding the sliding filament model is false?

ATP is required for the detachment of myosin heads from actin filaments.

Calcium ions bind to troponin, causing a conformational change that exposes binding sites on actin.

The length of the actin and myosin filaments changes during contraction.

During muscle contraction, the sarcomere shortens as actin and myosin filaments slide past each other.

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Verified step by step guidance

Understand the sliding filament model: This model explains how muscles contract by the sliding of actin and myosin filaments past each other, leading to the shortening of the sarcomere, the functional unit of muscle fibers.

Identify the role of ATP: ATP is crucial for muscle contraction as it provides the energy required for the detachment of myosin heads from actin filaments after a power stroke, allowing the cycle of muscle contraction to continue.

Recognize the role of calcium ions: Calcium ions bind to troponin, which causes a conformational change in the troponin-tropomyosin complex, exposing the binding sites on actin for myosin heads to attach and initiate contraction.

Clarify the misconception about filament length: During muscle contraction, the length of the actin and myosin filaments does not change. Instead, they slide past each other, which shortens the sarcomere and leads to muscle contraction.

Conclude with the false statement: The statement that the length of the actin and myosin filaments changes during contraction is false, as the filaments themselves remain the same length; it is the sarcomere that shortens.