Lecture 3

Question 1

What are functions of the skin?

Answer 1

• Thermoregulation
• Blood reservoir
• Protection
• Cutaneous sensations
• Excretion and absorption
• Synthesis of vitamin D

Question 2

What is the structure of skin like?

Answer 2

• Outer layer of the integument (Largest organ)
• Weighs about 4.5-5.0 kg (10-11 lb) which is about 7% of body weight
• Thickness ranges from 0.5 mm (0.02 in.; eyelids) to 5.0mm (0.2 in.; heels of the feet)

Question 3

What are the layers of skin?

Answer 3

Two majors layers: Epidermis (epithelial tissue, stratified squamous), and dermis (connective tissue, underlying epidermis)
- Subcutaneous (subQ) layer (also called hypodermis and where needles are given)
- Skin and subcutaneous layer form the integument

Question 4

Some components of the Integumentary System:

Answer 4

• Epidermis
• Dermis
• Subcutaneous tissue
• Blood vessels
  (Look on diagrams in slideshow)

Question 5

Types of Cells in the Epidermis (4)

Answer 5

1. Keratinocyte (Tough protein, makes waterproof)
2. Melanocyte (Make melanin, gives colour to our skin, can become cancerous)
3. Dendritic Cell (Immune cells, in epidermis, very important)
4. Tactile Epithelial Cell (How we feel)

Question 6

Layers of the Epidermis in order (5)

Answer 6

1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basale

Question 7

What is the Stratum basale?

Answer 7

Feeder layer, provides new cells to next. Deepest layer, separated from the dermis by the basement membrane and attached to basement membrane by hemidesmosomes.

Question 8

What is Stratum spinosum?

Answer 8

8-10 cell layers, also known as the prickle cell layer. Helps make your skin flexible and strong.

Question 9

What is Stratum granulosum?

Answer 9

Forms a waterproof barrier that functions to prevent fluid loss from the body, contains cells with keratohyalin granules and lamellar granules.

Question 10

What is Stratum lucidum?

Answer 10

Thin, clear layer of dead skin cells in the epidermis. Reduces friction between stratum corneum and stratum granulosum.

Question 11

What is the Stratum corneum?

Answer 11

Outermost layer of the epidermis. Barrier that prevents unwanted materials from entering and excessive loss of water from exiting the body.

Question 12

Two major types of skin

Answer 12

1. Thin (hairy) skin - no stratum lucidum
2. Thick (hairless) skin

Question 13

What is the Dermis composed of?

Answer 13

Strong dense irregular connective tissue containing collagen and elastic fibers.