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 of the following is true regarding a resting muscle fiber?

The concentration of calcium ions is higher in the sarcoplasmic reticulum than in the cytosol.

ATP is not present in the muscle fiber.

The sarcolemma is depolarized.

The actin and myosin filaments are actively sliding past each other.

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Verified step by step guidance

Understand the context of a resting muscle fiber: A resting muscle fiber is in a state where it is not actively contracting. This means that certain physiological conditions must be met, such as the absence of active sliding of actin and myosin filaments.

Review the role of calcium ions in muscle contraction: Calcium ions are stored in the sarcoplasmic reticulum during rest. When a muscle fiber is stimulated, calcium ions are released into the cytosol to initiate contraction. Therefore, in a resting state, the concentration of calcium ions is higher in the sarcoplasmic reticulum than in the cytosol.

Analyze the role of ATP in muscle fibers: ATP is always present in muscle fibers, even during rest, as it is required for maintaining cellular functions and preparing for contraction. The statement 'ATP is not present in the muscle fiber' is incorrect.

Examine the state of the sarcolemma: In a resting muscle fiber, the sarcolemma is polarized, meaning there is a difference in electrical charge across the membrane. Depolarization occurs only when the muscle fiber is stimulated.

Evaluate the interaction of actin and myosin filaments: During rest, actin and myosin filaments are not actively sliding past each other. Sliding occurs only during contraction when calcium ions bind to troponin, exposing binding sites on actin for myosin heads.