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

During the sliding filament theory, when does the myosin head cock back to store energy for the next cycle?

After ATP binds to the myosin head and is hydrolyzed to ADP and Pi

When calcium ions bind to troponin

During the power stroke when ADP is released

When the myosin head detaches from actin

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Verified step by step guidance

Understand the sliding filament theory: This theory explains how muscles contract by the interaction of actin and myosin filaments within the muscle cell. The myosin heads bind to actin, pull the actin filaments, and then release to repeat the cycle.

Identify the role of ATP in the cycle: ATP binds to the myosin head, causing it to detach from the actin filament. This is a crucial step in the cycle as it allows the myosin head to reset for another contraction.

Recognize the hydrolysis of ATP: Once ATP is bound to the myosin head, it is hydrolyzed into ADP and inorganic phosphate (Pi). This reaction releases energy, which is used to 'cock' the myosin head back into a high-energy state, ready for the next power stroke.

Consider the role of calcium ions: Calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from the binding sites on actin, allowing myosin heads to attach to actin and initiate the power stroke.

Sequence the events: After the power stroke, ADP is released, and a new ATP molecule binds to the myosin head, causing it to detach from actin. The ATP is then hydrolyzed, which cocks the myosin head back, storing energy for the next cycle.