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

First-Line Defenses: Chemical Barriers

Anatomy & Physiology

21. The Immune System

First-Line Defenses: Chemical Barriers

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Problem 7c

Textbook Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
NK cells are cytotoxic cells that lyse and kill cancer cells and cells infected with certain viruses.

Verified step by step guidance

Step 1: Understand the role of NK (Natural Killer) cells in the immune system. NK cells are a type of lymphocyte that play a critical role in the innate immune response. They are cytotoxic cells that target and destroy abnormal cells, such as cancer cells and cells infected with viruses.

Step 2: Evaluate the statement provided. The statement claims that NK cells are cytotoxic cells that lyse and kill cancer cells and cells infected with certain viruses. This aligns with the known function of NK cells in the immune system.

Step 3: Determine whether the statement is true or false. Based on the description of NK cells, the statement is true because it accurately describes their function.

Step 4: If the statement were false, you would need to correct it. For example, if the statement incorrectly described NK cells as part of the adaptive immune system, you would correct it by stating that NK cells are part of the innate immune system.

Step 5: Conclude that the statement is true and does not require correction, as it accurately reflects the role of NK cells in lysing and killing cancer cells and virus-infected cells.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Natural Killer (NK) Cells

Natural Killer (NK) cells are a type of lymphocyte in the immune system that play a crucial role in the body's defense against tumors and virally infected cells. They are part of the innate immune response and can recognize and destroy compromised cells without prior sensitization, making them essential for early immune responses.

Cytotoxic Activity

Cytotoxic activity refers to the ability of certain immune cells, such as NK cells, to kill target cells, including cancerous and infected cells. This process involves the release of cytotoxic granules containing perforin and granzymes, which induce apoptosis (programmed cell death) in the target cells, thereby eliminating the threat to the organism.

Immune Response

The immune response is the body's defense mechanism against pathogens, including viruses and cancer cells. It involves a complex interplay of various immune cells, signaling molecules, and mechanisms that work together to identify and eliminate harmful entities, ensuring the maintenance of health and homeostasis.