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

A contracting skeletal muscle fiber typically shortens as all of its ______ shorten in length.

sarcomeres

myofibrils

mitochondria

nuclei

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Verified step by step guidance

Step 1: Begin by understanding the structure of a skeletal muscle fiber. Skeletal muscle fibers are composed of myofibrils, which are further divided into repeating units called sarcomeres. Sarcomeres are the functional units responsible for muscle contraction.

Step 2: Recall the mechanism of muscle contraction. During contraction, the sarcomeres shorten as the actin and myosin filaments slide past each other. This process is known as the sliding filament theory.

Step 3: Eliminate incorrect options based on their roles. Mitochondria are responsible for energy production, not contraction. Nuclei are involved in genetic material storage and regulation, and they do not shorten during contraction.

Step 4: Consider the role of myofibrils. Myofibrils are composed of multiple sarcomeres arranged in series. While myofibrils contribute to the overall shortening of the muscle fiber, the actual shortening occurs at the sarcomere level.

Step 5: Conclude that the correct answer is 'sarcomeres,' as they are the specific structures within the muscle fiber that shorten during contraction.