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 organelle wraps around the myofibril and is responsible for storing calcium in muscle cells?

Nucleus

Mitochondrion

Golgi apparatus

Sarcoplasmic reticulum

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Verified step by step guidance

Step 1: Begin by understanding the structure of a muscle cell (also called a muscle fiber). Muscle cells contain specialized organelles that support contraction, including myofibrils, which are the contractile units of the cell.

Step 2: Learn about the role of calcium in muscle contraction. Calcium ions are essential for initiating the interaction between actin and myosin filaments within the myofibrils, leading to contraction.

Step 3: Identify the organelle responsible for storing and releasing calcium. The sarcoplasmic reticulum (SR) is a specialized form of the endoplasmic reticulum found in muscle cells. It wraps around the myofibrils and serves as a reservoir for calcium ions.

Step 4: Compare the functions of the other organelles listed in the question. The nucleus contains genetic material, the mitochondrion produces ATP for energy, and the Golgi apparatus processes and packages proteins. None of these are directly involved in calcium storage for muscle contraction.

Step 5: Conclude that the sarcoplasmic reticulum is the correct answer because it is specifically adapted to store and release calcium ions, which are critical for muscle contraction.