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 theory explains how muscle fibers shorten during contraction?

All-or-none law

Cross-bridge cycling theory

Length-tension relationship

Sliding filament theory

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Verified step by step guidance

Step 1: Begin by understanding the concept of muscle contraction. Muscle fibers shorten during contraction due to interactions between actin and myosin filaments within the sarcomere, the functional unit of a muscle.

Step 2: Learn about the Sliding Filament Theory, which explains how muscle contraction occurs. According to this theory, actin (thin filaments) and myosin (thick filaments) slide past each other, causing the sarcomere to shorten without the filaments themselves changing length.

Step 3: Explore the role of cross-bridge cycling in the Sliding Filament Theory. Myosin heads attach to actin filaments, forming cross-bridges. These heads then pivot, pulling the actin filaments toward the center of the sarcomere, and detach to repeat the cycle.

Step 4: Understand the importance of ATP in this process. ATP is required for the myosin heads to detach from actin and reset for another cycle of contraction. Without ATP, the cross-bridge cycling cannot continue.

Step 5: Review the structural changes during contraction. The I-band (region of actin not overlapped by myosin) and the H-zone (region of myosin not overlapped by actin) decrease in size, while the A-band (length of the myosin filament) remains constant, confirming the sliding mechanism.