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

Which region of the sarcomere does not change in length during muscle contraction?

Z disc

H zone

A band

I band

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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 repeating units of actin (thin filaments) and myosin (thick filaments). Key regions include the Z disc, A band, I band, and H zone.

Learn the role of the A band: The A band is the region of the sarcomere that contains the entire length of the thick filaments (myosin). It also overlaps with thin filaments (actin) in certain areas.

Analyze what happens during muscle contraction: During contraction, the sarcomere shortens as the actin filaments slide over the myosin filaments. This causes changes in the lengths of the I band and H zone, but the A band remains constant because the length of the thick filaments does not change.

Compare the regions: The Z disc marks the boundary of the sarcomere and moves closer together during contraction. The I band (thin filaments only) and H zone (region with thick filaments only) decrease in length, while the A band remains unchanged.

Conclude that the A band does not change in length during muscle contraction, as it represents the fixed length of the thick filaments within the sarcomere.