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

Introduction to Muscles and Muscle Tissue

Anatomy & Physiology

9. Muscle Tissue

Introduction to Muscles and Muscle Tissue

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Multiple Choice

Which type of lever is exemplified by the flexing of the forearm by the biceps brachii muscle?

Second-class lever

First-class lever

Fourth-class lever

Third-class lever

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Verified step by step guidance

Understand the concept of levers in the human body: Levers are classified into three types based on the arrangement of the fulcrum, effort, and load. These are first-class, second-class, and third-class levers.

Review the anatomy of the forearm and biceps brachii muscle: The biceps brachii muscle is responsible for flexing the forearm at the elbow joint. The elbow joint acts as the fulcrum, the biceps brachii provides the effort, and the forearm (along with any weight being lifted) represents the load.

Identify the characteristics of a third-class lever: In a third-class lever, the effort is applied between the fulcrum and the load. This arrangement is designed for speed and range of motion rather than force.

Apply the lever classification to the forearm flexion: In the case of forearm flexion, the elbow joint is the fulcrum, the biceps brachii applies the effort in the middle, and the forearm (and any weight) is the load at the end. This matches the definition of a third-class lever.

Conclude that the flexing of the forearm by the biceps brachii muscle is an example of a third-class lever based on the arrangement of the fulcrum, effort, and load.