Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 39m
3. Energy & Cell Processes10h 8m
4. Tissues & Histology10h 3m
5. Integumentary System2h 28m
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 System3h 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

In the respiratory burst, __________ are released; these have a potent cell-killing ability.

neutrophils

platelet-derived growth factors

free radicals

histamines

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Verified step by step guidance

Understand the context of the respiratory burst: It is a rapid release of reactive oxygen species (ROS) from different types of cells, most notably phagocytes like neutrophils, during the process of phagocytosis.

Identify the key players involved in the respiratory burst: Neutrophils are the primary cells that undergo respiratory burst to kill pathogens.

Recognize the substances released during the respiratory burst: The process involves the production of free radicals, which are highly reactive molecules that can damage or kill cells.

Differentiate between the options provided: Neutrophils are the cells involved, not the substances released. Platelet-derived growth factors and histamines are not related to the respiratory burst.

Conclude that free radicals are the correct answer: Free radicals, such as superoxide anions, hydrogen peroxide, and hydroxyl radicals, are the potent cell-killing agents released during the respiratory burst.