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

The T tubules of a muscle fiber are extensions of the:

sarcoplasmic reticulum

myofibrils

endomysium

sarcolemma

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Verified step by step guidance

Understand the structure of a muscle fiber: A muscle fiber is composed of several key components, including the sarcolemma (plasma membrane), sarcoplasmic reticulum (specialized endoplasmic reticulum), myofibrils (contractile units), and connective tissue layers like the endomysium.

Learn the function of T tubules: T tubules (transverse tubules) are invaginations of the sarcolemma that penetrate deep into the muscle fiber. Their role is to conduct action potentials from the surface of the muscle fiber to the interior, ensuring synchronized contraction.

Differentiate the components: The sarcoplasmic reticulum stores calcium ions and is involved in calcium release during muscle contraction. Myofibrils are the structures responsible for contraction, and the endomysium is a connective tissue layer surrounding individual muscle fibers. None of these are directly involved in forming T tubules.

Connect the concept: Since T tubules are extensions of the sarcolemma, they are continuous with the plasma membrane and help propagate electrical signals into the muscle fiber.

Conclude the reasoning: Based on the structure and function of T tubules, the correct answer is that they are extensions of the sarcolemma, not the sarcoplasmic reticulum, myofibrils, or endomysium.