CDT Skin Anatomy & Physiology 1 — Questions and Answers
Question 1: Which layer of the skin is responsible for waterproofing and protection?
- Dermis
- Subcutaneous layer
- Epidermis (Correct answer)
- Basement membrane
Correct answer: Epidermis
The epidermis is the outermost layer of the skin, primarily composed of keratinocytes. These cells produce keratin, a tough, fibrous protein that forms a protective barrier against physical damage, pathogens, and UV radiation. The stratum corneum, the outermost part of the epidermis, is particularly rich in keratin and lipids, providing the essential waterproofing function.
Question 2: What is the primary function of the dermis?
- Fat storage
- Barrier formation
- Support and nourishment (Correct answer)
- Vitamin D synthesis
Correct answer: Support and nourishment
The dermis is the thick, middle layer of the skin, located beneath the epidermis. It provides structural support to the skin through its rich network of collagen and elastin fibers, giving skin its strength and elasticity. Additionally, it contains blood vessels that supply nutrients and oxygen to the avascular epidermis, as well as nerves, hair follicles, and glands.
Question 3: Which cells produce melanin?
- Keratinocytes
- Fibroblasts
- Melanocytes (Correct answer)
- Langerhans cells
Correct answer: Melanocytes
Melanocytes are specialized cells found in the basal layer of the epidermis. Their primary function is to produce melanin, a pigment responsible for skin, hair, and eye color. Melanin also plays a crucial role in protecting the skin from harmful ultraviolet (UV) radiation by absorbing it, thereby preventing DNA damage.
Question 4: Which layer contains blood vessels and nerves?
- Epidermis
- Stratum basale
- Dermis (Correct answer)
- Stratum corneum
Correct answer: Dermis
The dermis is the middle layer of the skin, located beneath the epidermis. It is rich in connective tissue, blood vessels, nerves, hair follicles, and glands, making it responsible for providing nutrients to the epidermis, regulating temperature, and mediating sensations.
Question 5: What is the role of sebaceous glands?
- Sweat production
- Vitamin D synthesis
- Sebum production (Correct answer)
- Keratin production
Correct answer: Sebum production
Sebaceous glands are exocrine glands found in the skin, primarily associated with hair follicles. Their main function is to produce and secrete sebum, an oily substance that lubricates the skin and hair, helping to keep them moisturized and protected.
Question 6: What is keratin?
- A pigment
- A connective tissue
- A protein providing structure and protection (Correct answer)
- A hormone
Correct answer: A protein providing structure and protection
Keratin is a tough, fibrous protein that is the primary structural component of the epidermis, hair, and nails. It provides strength, impermeability, and protection against physical damage, water loss, and microbial invasion, forming the skin's protective barrier.
Question 7: Which skin function involves heat regulation?
- Immune protection
- Sensation
- Thermoregulation (Correct answer)
- Vitamin storage
Correct answer: Thermoregulation
Thermoregulation is the process by which the body maintains its core internal temperature. The skin plays a crucial role in this by regulating blood flow (vasodilation/vasoconstriction) and through sweat production, which cools the body via evaporation.
Question 8: Which skin layer undergoes mitosis to create new skin cells?
- Stratum corneum
- Stratum granulosum
- Stratum basale (Correct answer)
- Stratum lucidum
Correct answer: Stratum basale
The stratum basale (also known as stratum germinativum) is the deepest layer of the epidermis. It contains actively dividing keratinocytes that undergo mitosis to continuously produce new skin cells, which then migrate upwards through the epidermal layers.
Question 9: How does the skin participate in immune defense?
- By producing antibodies
- Through Langerhans cells (Correct answer)
- By secreting melanin
- Via sweat production
Correct answer: Through Langerhans cells
Langerhans cells are specialized dendritic cells found in the epidermis. They are a crucial part of the skin's immune system, acting as antigen-presenting cells that capture and process foreign antigens, then migrate to lymph nodes to initiate an immune response.
CDT Skin Anatomy & Physiology 1
Which layer of the skin is responsible for waterproofing and protection?