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

21. The Immune System

Introduction to the Immune System

Anatomy & Physiology

21. The Immune System

Introduction to the Immune System

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Multiple Choice

Which of the following statements regarding the thymus is NOT true?

The thymus is most active during childhood.

The thymus is the primary site for T cell maturation.

The thymus produces antibodies to fight infections.

The thymus gradually decreases in size after puberty.

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Verified step by step guidance

Step 1: Begin by understanding the role of the thymus in the immune system. The thymus is a specialized organ located in the mediastinum, and its primary function is to support the maturation of T lymphocytes (T cells), which are critical for adaptive immunity.

Step 2: Review the statement 'The thymus is most active during childhood.' This is true because the thymus is largest and most active during childhood, playing a key role in developing the immune system. After puberty, it gradually decreases in size and activity, a process known as involution.

Step 3: Examine the statement 'The thymus is the primary site for T cell maturation.' This is also true. Immature T cells migrate to the thymus, where they undergo selection processes to ensure they can recognize antigens and function properly in the immune system.

Step 4: Analyze the statement 'The thymus produces antibodies to fight infections.' This is NOT true. The thymus does not produce antibodies; antibody production is the role of B cells, which mature in the bone marrow and differentiate into plasma cells to produce antibodies.

Step 5: Confirm the statement 'The thymus gradually decreases in size after puberty.' This is true, as the thymus undergoes involution, becoming smaller and less active with age, although it still retains some function in T cell maturation.