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

The Epidermis: Layers

Anatomy & Physiology

5. Integumentary System

The Epidermis: Layers

Previous problemNext problem

Problem L3.A2

Textbook Question

After Ramon's skin came into contact with a poison ivy plant in biology lab, he developed a painful, itchy rash. However, after the skin of his colleague Cathy came into contact with snake venom in the lab, she developed no skin irritation. Poison ivy plants contain lipid-soluble oils, whereas snake venoms contain mostly water-soluble peptides. Explain why Ramon developed a rash, whereas Cathy did not.

Verified step by step guidance

Understand the nature of the substances involved: Poison ivy contains lipid-soluble oils (urushiol), while snake venom contains water-soluble peptides. Lipid-soluble substances can easily penetrate the lipid bilayer of cell membranes, whereas water-soluble substances cannot cross the lipid bilayer without specific transport mechanisms.

Recall the structure of the skin: The outermost layer of the skin, the stratum corneum, is composed of dead keratinized cells and lipids, forming a barrier that is more permeable to lipid-soluble substances than water-soluble ones.

Explain Ramon's reaction: The lipid-soluble oils from poison ivy (urushiol) can penetrate the lipid-rich stratum corneum of Ramon's skin. Once inside, urushiol triggers an immune response by binding to skin proteins, forming complexes that are recognized as foreign by the immune system, leading to an allergic reaction and rash.

Explain Cathy's lack of reaction: Snake venom, being water-soluble, cannot easily penetrate the lipid-rich stratum corneum of the skin. Without penetration, the venom does not interact with the immune system or underlying tissues, resulting in no skin irritation.

Summarize the difference: Ramon developed a rash because the lipid-soluble urushiol from poison ivy could penetrate his skin and trigger an immune response. Cathy did not develop a rash because the water-soluble peptides in snake venom could not penetrate her skin's lipid barrier.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Lipid-Soluble vs. Water-Soluble Substances

Lipid-soluble substances can easily penetrate cell membranes, which are primarily composed of lipid bilayers. In contrast, water-soluble substances do not easily cross these membranes. In Ramon's case, the lipid-soluble oils from poison ivy penetrated his skin, triggering an immune response that resulted in a rash. Cathy's exposure to water-soluble snake venom did not penetrate her skin in the same way, leading to no irritation.

Immune Response

The immune response is the body's defense mechanism against harmful substances. When Ramon came into contact with poison ivy, his immune system recognized the lipid-soluble oils as foreign invaders, leading to an inflammatory response characterized by redness, swelling, and itching. This response is part of a hypersensitivity reaction, which can occur upon first exposure to certain allergens, like those found in poison ivy.

Allergic Reactions

An allergic reaction occurs when the immune system overreacts to a substance that is typically harmless. In the case of poison ivy, the oils can sensitize the skin, leading to an allergic dermatitis upon subsequent exposures. Cathy's lack of reaction to snake venom suggests that her immune system did not recognize it as a threat, indicating that she either did not have a prior sensitization or that the venom did not trigger an allergic response.

Watch next

Master Introduction to Layers of the Epidermis with a bite sized video explanation from Bruce Bryan

Start learning

Related Videos

Related Practice

Textbook Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Carotene is a brown-black pigment that accumulates in the stratum corneum.

659

views

Textbook Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Increased amounts of blood flowing through the dermis lead to pallor in the skin.

547

views

Textbook Question

Which type of burn involves the epidermis and all or part of the dermis?

a. First-degree burn

b. Second-degree burn

c. Third-degree burn

d. Fourth-degree burn

490

views

Textbook Question

The type of skin tumor that involves the keratinocytes of the stratum spinosum is:

a. Basal cell carcinoma

b. Squamous cell carcinoma

c. Malignant keratocytoma

d. Malignant melanoma

Many antiaging skin creams contain collagen and hyaluronic acid. Manufacturers claim that the collagen and hyaluronic acid applied to the surface of the skin will be absorbed into the dermis, where they will be incorporated into dermal tissue.

Are these substances polar or nonpolar?

376

views

Textbook Question

Predict whether or not these substances are likely to be absorbed by the epidermis.

395

views

Textbook Question

Predict the effectiveness of the creams.

395

views

Multiple Choice