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

During a twitch in a skeletal muscle fiber, what occurs during the latent period?

The muscle fiber is actively shortening and generating tension.

The muscle fiber is relaxing and returning to its resting length.

Calcium ions are released from the sarcoplasmic reticulum, but no visible contraction occurs yet.

ATP is being depleted and the muscle enters a state of fatigue.

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Verified step by step guidance

Understand the concept of a muscle twitch: A muscle twitch is a single, brief contraction and relaxation cycle in a skeletal muscle fiber in response to a single stimulus.

Identify the phases of a muscle twitch: The three phases are the latent period, contraction phase, and relaxation phase. The latent period is the initial phase after the stimulus but before visible contraction begins.

Explain the latent period: During the latent period, the muscle fiber is preparing for contraction. This involves the release of calcium ions (Ca²⁺) from the sarcoplasmic reticulum into the cytosol, which is triggered by the action potential traveling along the sarcolemma.

Describe the role of calcium ions: Calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from the binding sites on actin filaments. This step is crucial for the subsequent cross-bridge formation during the contraction phase.

Clarify why no visible contraction occurs: Although molecular events like calcium release and troponin-tropomyosin interaction are happening during the latent period, these processes do not yet result in visible shortening or tension generation in the muscle fiber.