Skin and Fascia 1: Epidermis

Question 1

What are the functions of the skin?

Answer 1

Function 1: Protection
Function 2: Sensation
Function 3: Excretion
Function 4: Thermoregulation
Function 5: Metabolic

Question 2

Describe the protective functions of the skin

Function 1

Answer 2

Cushions and insulates deeper organs
Ultraviolet light & microorganisms
Abrasion, trauma, chemical, mechanical insults
Prevents water loss

Question 3

What sensations can be detected by the skin?

Function 2

Answer 3

Contains sensory receptors for Pain, Pressure, Touch & Temperature

Question 4

What are the excretions of the skin?

Function 3

Answer 4

Sweat

Question 5

How is skin involved in thermoregulation?

Function 4

Answer 5

Vasodilation & Vasoconstriction

Question 6

Describe the metabolic functions of the skin

Function 5

Answer 6

Vitamin D synthesis

Question 7

What are the layers of the skin?

Answer 7

Epidermis: Superficial stratified squamous epithelium layer
Dermis: Deep connective tissue layer

Question 8

What lies deep to the dermis layer of skin?

Answer 8

Hypodermis/subcutaneous layer
It is a layer of areolar and adipose connective tissue
Not considered part of the skin

Question 9

What are the layers of the epidermis?

Answer 9

Deep to superficial (Britney Spears Gives Lovely Concerts):
1. Stratum basale/stratum germinativum
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum

Question 10

Features of stratum basale

Answer 10

Continuous cell division occurs to produce all the other layers

Question 11

Features of stratum spinosum

Answer 11

8-10 layers of keratinocytes

Question 12

Features of stratum granulosum

Answer 12

Includes keratohyalin and lamellar granules

Question 13

Features of stratum lucidum

Answer 13

Present only in thick skin, e.g. skin of the fingertips, palms, and soles

Question 14

Features of stratum corneum

Answer 14

Composed of many sublayers of flat, dead keratinocytes called corneocytes or squames
They are continuously shed and replaced by cells from deeper strata

Constant friction can stimulate formation of a callus.

Question 15

What are the 4 major types of epidermal cells?

Answer 15

Keratinocytes: Produce keratin (a tough fibrous protein) that provides protection. Forms 90% of the epidermal layer
Melanocytes: Produce melanin pigment which protects against damage by UV radiation
Langerhans Cells: Cells arising from red bone marrow which trigger immune reactions
Merkel Cells: Function in the sensation of touch along with adjacent tactile discs

Question 16

What are the differences between thick skin and thin skin?

Answer 16