Integumentary System

Question 1

What are the 6 functions of skin?

Answer 1

1. Boundary/protection from the external environment.
2. Secretes and absorbs substances.
3. Regulates body temperature.
4. Stores blood.
5. Detects cutaneous sensations.
6. Synthesizes vitamin D.

Question 2

Describe skins gross anatomy

Answer 2

Location = Covers whole body.
Shape, size + appearance = 1.5-2 square meters in area, 0.5-4mm thick averaging at 1-2mm, pigmented + contains accessory structures.
Relations = Superficial to all other structures and continuous with some mucous membranes.
Lymphatic drainage = Extensive and diffuse.
Bloody supply and drainage = Extensive and diffuse.

Question 3

Epidermis Structure

Answer 3

Keratinized stratified squamous epithelium. Composed of 5-6 layers: (stratum)
- Basale (skin stem cells)
- Spinosum (active keratinocytes)
- Granulosum (dying keratinocytes)
- Lucidum (only present in thicker skin, clear dead keratinocytes)
- Corneum (dead keratinocytes).

Question 4

Describe the 4 cell types of the epidermis

Answer 4

1. Keratinocytes = produce keratin protein which protects skin and underlying tissue as well as a waterproof sealant (lamellar granules). Located in 4-5 layers.
2. Melanocytes = Produce pigment melanin, contribute to skin color and absorb damaging UV rays. Located in the basal layer.
3. Langerhans cells = Participate in immune response, recognizes invading microbes and helps other cells to destroy them. Migrate from red bone marrow.
4. Merkel cells = Detect touch sensations with the help of tactile discs. Located in the deepest layer.

Question 5

Dermis Structure

Answer 5

Dense irregular connective tissue with collagen and elastic fibers. Contains blood vessels, nerves, hair follicles and glands.

Question 6

Describe the 3 cell types of the dermis

Answer 6

1. Fibroblasts = secrete collagen and elastic fibers.
2. Macrophages = Immune response
3. Adipocytes = store fat, (very few near subcutaneous layer).

Question 7

Describe structure of hair and nails

Answer 7

Hair = Made up of dead keratinized cells. Follicle hold root in dermis, shoot then breaks through the epidermis.
Nails = Made up of hard keratinized cells. Covers dorsal surfaces of fingers and toes.

Question 8

What are the 2 types of glands

Answer 8

1. Sweat
2. Oil

Question 9

Describe both Eccrine and Apocrine glands

Answer 9

Eccrine = Large in number, more superficial, open onto skin, function to cool body down + eliminate waste.
Apocrine = Smaller in number, open onto hair follicle, function during emotional stress + sexual excitement.

Question 10

What are dermal papillae and epidermal ridges

Answer 10

Dermal papillae and epidermal ridges are small structures on the surface of the dermis and underside of the epidermis, they function to both increase surface area and strengthen bond between between each other by resisting sheer force in multiple directions.