Table of contents

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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

Introduction to First-Line Defenses

Anatomy & Physiology

21. The Immune System

Introduction to First-Line Defenses

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Multiple Choice

How do cilia function as a first-line defense to prevent infection?

Cilia increase the acidity of the skin to inhibit pathogen growth.

Cilia secrete enzymes that digest pathogens.

Cilia produce antibodies to neutralize pathogens.

Cilia trap and move pathogens out of the respiratory tract.

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Verified step by step guidance

Understand the role of cilia in the respiratory system: Cilia are tiny hair-like structures that line the respiratory tract, including the nasal passages, trachea, and bronchi.

Recognize the function of cilia: Cilia work in conjunction with mucus to trap inhaled particles, such as dust, bacteria, and viruses, preventing them from reaching the lungs.

Learn about the movement of cilia: Cilia beat in a coordinated, wave-like motion, moving the trapped particles upwards towards the throat where they can be swallowed or expelled.

Differentiate cilia from other defense mechanisms: Unlike acidity, enzymes, or antibodies, cilia do not chemically alter pathogens but physically move them out of the respiratory tract.

Conclude the primary defense mechanism: Cilia act as a mechanical barrier, effectively trapping and moving pathogens out of the respiratory tract to prevent infection.