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

In the process of excitation-contraction coupling in skeletal muscle, which step is indicated by 'a' if it refers to the release of calcium ions from the sarcoplasmic reticulum?

Myosin heads bind to actin forming cross-bridges.

The action potential travels along the sarcolemma and down the T-tubules.

Acetylcholine is released from the motor neuron into the synaptic cleft.

Calcium ions are released from the sarcoplasmic reticulum into the cytosol.

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Verified step by step guidance

Step 1: Understand the concept of excitation-contraction coupling in skeletal muscle. This process links the electrical signal (action potential) to the mechanical contraction of the muscle fibers.

Step 2: Recognize the role of calcium ions in this process. Calcium ions are stored in the sarcoplasmic reticulum and are released into the cytosol when triggered by an action potential.

Step 3: Identify the sequence of events in excitation-contraction coupling: (1) Acetylcholine is released from the motor neuron into the synaptic cleft, (2) The action potential travels along the sarcolemma and down the T-tubules, (3) Calcium ions are released from the sarcoplasmic reticulum into the cytosol, and (4) Myosin heads bind to actin forming cross-bridges.

Step 4: Focus on the specific step indicated by 'a' in the problem. The release of calcium ions from the sarcoplasmic reticulum into the cytosol is the key event that allows the muscle contraction to proceed.

Step 5: Relate this step to its physiological importance. Calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from the actin binding sites, enabling myosin heads to form cross-bridges with actin and initiate contraction.