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

9. Muscle Tissue

Sliding Filament Theory and the Sacromere

Anatomy & Physiology

9. Muscle Tissue

Sliding Filament Theory and the Sacromere

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Multiple Choice

What changes occur in the sarcomere during muscle contraction?

The H zone widens and the I band lengthens.

The A band shortens and the I band remains the same length.

The I band shortens and the A band remains the same length.

Both the A band and I band lengthen.

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Verified step by step guidance

Understand the structure of the sarcomere: The sarcomere is the functional unit of a muscle fiber, composed of thick (myosin) and thin (actin) filaments. It includes regions such as the A band, I band, H zone, and Z lines.

Identify the components of the sarcomere: The A band contains the entire length of the thick filaments and remains constant during contraction. The I band contains only thin filaments and is the region that changes length during contraction.

Recognize the process of muscle contraction: During contraction, the actin filaments slide over the myosin filaments, causing the sarcomere to shorten. This sliding filament mechanism results in the shortening of the I band.

Analyze the changes in the sarcomere: As the muscle contracts, the I band shortens because the actin filaments are pulled towards the center of the sarcomere. The A band remains the same length because it is defined by the length of the myosin filaments, which do not change.

Conclude the changes during contraction: The correct observation during muscle contraction is that the I band shortens while the A band remains the same length, reflecting the sliding filament theory of muscle contraction.