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

Which structure in a myofibril is responsible for storing and releasing calcium ions during muscle contraction?

Mitochondrion

Sarcoplasmic reticulum

T-tubule

Sarcolemma

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Verified step by step guidance

Understand the role of calcium ions in muscle contraction: Calcium ions are essential for initiating the interaction between actin and myosin filaments, which leads to muscle contraction.

Identify the structure responsible for storing calcium ions: In muscle cells, calcium ions are stored in a specialized organelle called the sarcoplasmic reticulum (SR). This structure is a network of membranous tubules surrounding the myofibrils.

Understand the release mechanism: During muscle contraction, the sarcoplasmic reticulum releases calcium ions into the cytoplasm in response to an action potential transmitted through the T-tubules.

Differentiate the options: The mitochondrion is responsible for energy production, the T-tubule transmits the action potential, and the sarcolemma is the plasma membrane of the muscle cell. None of these structures store calcium ions like the sarcoplasmic reticulum does.

Conclude that the sarcoplasmic reticulum is the correct answer because it is specifically designed to store and release calcium ions during muscle contraction.