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

5. Integumentary System

Introduction to the Integumentary System

Anatomy & Physiology

5. Integumentary System

Introduction to the Integumentary System

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Multiple Choice

Why are keratinocytes no longer viable in the stratum lucidum of the epidermis?

They are filled with melanin and continue to synthesize proteins.

They have lost their nuclei and organelles due to the process of keratinization.

They are actively dividing and producing new cells.

They receive abundant nutrients from underlying blood vessels.

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Verified step by step guidance

Understand the structure of the epidermis: The epidermis is composed of several layers, including the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. The stratum lucidum is found only in thick skin, such as the palms and soles.

Learn about keratinization: Keratinization is the process by which keratinocytes (skin cells) produce keratin, a tough protein, and gradually lose their nuclei and organelles as they move upward through the layers of the epidermis.

Focus on the stratum lucidum: In the stratum lucidum, keratinocytes are no longer viable because they have undergone keratinization. This means they have lost their nuclei and organelles, making them unable to carry out normal cellular functions.

Eliminate incorrect options: The keratinocytes in the stratum lucidum are not actively dividing, synthesizing proteins, or receiving nutrients from blood vessels. These processes occur in the lower layers of the epidermis, such as the stratum basale and stratum spinosum.

Conclude the reasoning: The correct answer is that keratinocytes in the stratum lucidum are no longer viable because they have lost their nuclei and organelles due to the process of keratinization. This is a key characteristic of this layer of the epidermis.