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 muscle is the primary agonist responsible for flexion of the arm at the shoulder joint?

Trapezius

Deltoid

Pectoralis major

Latissimus dorsi

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Verified step by step guidance

Understand the term 'primary agonist': In anatomy, the primary agonist is the muscle primarily responsible for producing a specific movement. In this case, the movement is flexion of the arm at the shoulder joint.

Review the action of each muscle listed: The trapezius is primarily involved in scapular movements (elevation, depression, retraction), not arm flexion. The deltoid assists in arm abduction and flexion but is not the primary agonist. The latissimus dorsi is responsible for arm extension, adduction, and medial rotation, not flexion.

Focus on the pectoralis major: This muscle originates from the clavicle, sternum, and ribs, and inserts into the humerus. Its primary function includes flexion, adduction, and medial rotation of the arm at the shoulder joint.

Correlate the movement with the muscle's function: Flexion of the arm at the shoulder joint involves moving the arm forward and upward, which aligns with the action of the pectoralis major.

Conclude that the pectoralis major is the primary agonist for this movement, as it is the muscle most directly responsible for flexion of the arm at the shoulder joint.