Table of contents

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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

Steps of Muscle Contraction

Anatomy & Physiology

9. Muscle Tissue

Steps of Muscle Contraction

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Multiple Choice

When does the sarcoplasmic reticulum release calcium during muscle contraction?

During the hyperpolarization of the muscle fiber membrane

During the depolarization of the muscle fiber membrane

During the repolarization of the muscle fiber membrane

When the muscle fiber is at rest

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Verified step by step guidance

Understand the role of the sarcoplasmic reticulum (SR) in muscle contraction: The SR stores calcium ions (Ca²⁺) and releases them to initiate muscle contraction.

Recognize the phases of the muscle fiber membrane potential: depolarization, repolarization, and hyperpolarization.

Identify that during depolarization, the muscle fiber membrane potential becomes less negative, which is a signal for the SR to release calcium ions.

Know that the release of calcium ions from the SR into the cytoplasm of the muscle cell is crucial for the interaction between actin and myosin, leading to muscle contraction.

Conclude that the release of calcium from the SR occurs during the depolarization phase of the muscle fiber membrane, not during hyperpolarization, repolarization, or when the muscle is at rest.