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

Natural Killer Cells

Anatomy & Physiology

21. The Immune System

Natural Killer Cells

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Multiple Choice

Certain viruses have evolved to be able to avoid detection by cytotoxic T cells. These viruses remove the MHC class 1 molecules from the surface of the cell that they are infecting. This ensures that the cytotoxic T cells do not bind to the infected cell and kill the cell and the virus within. Which immune cell is specifically designed to recognize these types of viral threats?

CD4 effector cells.

T helper cells.

Regulatory T cells.

Natural killer cells.

CD8 effector cells.

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Verified step by step guidance

Understand the role of MHC class 1 molecules: MHC class 1 molecules present endogenous antigens (such as viral proteins) on the surface of infected cells, allowing cytotoxic T cells (CD8+ T cells) to recognize and destroy these cells.

Recognize the problem: Certain viruses can evade detection by removing MHC class 1 molecules from the cell surface, preventing CD8+ T cells from recognizing and killing the infected cells.

Identify the immune cell type: Natural killer (NK) cells are a type of lymphocyte that can recognize and kill cells lacking MHC class 1 molecules. They are part of the innate immune system and can target cells that have downregulated MHC class 1, a common viral evasion strategy.

Differentiate between immune cells: CD4 effector cells, T helper cells, and regulatory T cells are primarily involved in coordinating the immune response and do not directly kill infected cells. CD8 effector cells require MHC class 1 for activation, unlike NK cells.

Conclude the solution: Natural killer cells are specifically designed to recognize and eliminate cells that have lost MHC class 1 expression, making them effective against viruses that use this evasion strategy.