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

Physical Barriers in First-Line Defenses: Skin

Anatomy & Physiology

21. The Immune System

Physical Barriers in First-Line Defenses: Skin

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Multiple Choice

Which of the following is considered to be a barrier to entry of a pathogen?

Antibodies

Skin

Lymph nodes

White blood cells

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Verified step by step guidance

Understand the concept of barriers to pathogen entry: Barriers are physical or chemical structures that prevent pathogens from entering the body and causing infection.

Identify the types of barriers: The primary physical barrier is the skin, which acts as a protective layer preventing pathogens from entering the body.

Consider the role of skin: The skin is the largest organ of the body and serves as a first line of defense by providing a physical barrier that is difficult for pathogens to penetrate.

Differentiate between skin and other immune components: While antibodies, lymph nodes, and white blood cells are crucial for immune response, they are not physical barriers. They function within the body to identify and eliminate pathogens.

Conclude that skin is the correct answer: Based on the understanding of physical barriers, skin is considered a barrier to entry of a pathogen, as it prevents pathogens from entering the body.