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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Multiple Choice

Which type of molecule is produced by virus-infected cells to communicate to noninfected cells the presence of a virus?

interferon

interleukin

antigen

pyrogen

complement

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Verified step by step guidance

Understand the context: When a cell is infected by a virus, it needs to alert neighboring cells to prepare defenses against the viral threat.

Identify the function of each molecule option: Interferons are proteins that are produced by virus-infected cells to signal neighboring cells to increase their antiviral defenses.

Differentiate between the options: Interleukins are involved in communication between white blood cells, antigens are substances that provoke an immune response, pyrogens cause fever, and complements are part of the immune system that enhances the ability to clear pathogens.

Focus on the role of interferons: They are specifically known for their role in antiviral defense, making them the correct choice for signaling the presence of a virus.

Conclude that interferons are the molecules produced by virus-infected cells to communicate the presence of a virus to noninfected cells.