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 Heart2h 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

Activation of T Lymphocytes

Anatomy & Physiology

21. The Immune System

Activation of T Lymphocytes

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Multiple Choice

Before T cells become activated, they require an antigen encounter. Naive T cells are shown to express L-selectin which aids in binding to high endothelial cells expressing L-selectin ligand in regions where they are most likely to encounter an antigen. In which of the following locations are these high endothelial cells most likely to be located?

Bone marrow.

Capillaries.

Lymph nodes.

Heart.

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Verified step by step guidance

Understand the role of naive T cells: Naive T cells are a type of lymphocyte that have not yet encountered an antigen. They circulate through the body looking for antigens to bind to and become activated.

Learn about L-selectin: L-selectin is a molecule expressed on the surface of naive T cells. It plays a crucial role in the homing of these cells to specific sites in the body where they are likely to encounter antigens.

Identify the function of high endothelial venules (HEVs): HEVs are specialized blood vessels found in certain lymphoid tissues. They express L-selectin ligands, which are molecules that bind to L-selectin on naive T cells, facilitating their entry into the tissue.

Determine the location of HEVs: High endothelial venules are primarily located in lymph nodes. These structures are part of the lymphatic system and serve as sites where immune responses are initiated.

Conclude the reasoning: Since naive T cells express L-selectin to bind to L-selectin ligands on high endothelial cells, and these cells are predominantly found in lymph nodes, the lymph nodes are the most likely location for naive T cells to encounter antigens.