Skin structure and function

Question 1

5 Main functions of skin

Answer 1

Protection from external damage - UV, Chemical, mechanical
Barrier - waterproof
Sensation - touch, pressure, pain
Metabolic - Synthesises vitamin D3, Energy store
Thermoregulation - Insulation, sweat, vasoconstriction/dilation

Question 2

3 main structural sub-components

Answer 2

Epidermis - stratified squamous keratinised epithelium
Dermis - Papillary dermis/Reticular dermis
Hypodermis/subcutis

Question 3

What are the 5 stratum layers?

Answer 3

Basale - base
Spinosum - Prickle cells
Granulosum
Licidum
Corneum

Question 4

Describe the stratum basale

Answer 4

Cuboidal
Attached to the basement membrane by hemidesmosomes
Mitosis to produce keratinocytes and migrates to surface

Question 5

Describe the stratum spinosum

Answer 5

Large and polyhedral but flatten as they migrate upwards
Tonofibrils which project into the cytoplasm and connect cells together via desmosomes
Lamellar body which elads to waterproof layer

Question 6

Describe the stratum granulosum

Answer 6

Flatter

Granules of keratohyalin which forms mature keratin complex

Question 7

Describe the stratum lucidum

Answer 7

Layer of dead cells between the granulosum and the corneum

Lysosomal enzymes breakdown organelles and cause lysis

Question 8

Describe the stratum corneum

Answer 8

Flattened dead cells with only mature keratin inside
Release hydrophobic glycophospholipid for waterproofing
Constantly being replaced

Question 9

What are the 4 main cell types?

Answer 9

Keratinocytes - 95% of total
Melanocytes - Responsible for skin and hair colour
Langerhans cells - Antigen presenting cells
Merkel cells - Neuroendocrine function

Question 10

What causes skin pigmentation?

Answer 10

Activity of the melanocytes in the area

Question 11

What is found in the papillary dermis and reticular dermis?

Answer 11

Papillary - Vascularised tissue. lymph and nerves

Reticular - Hair and glands

Question 12

What are the 4 main skin specialisations?

Answer 12

Rete ridges
Hair follicles
Sebaceous glands
Sweat glands

Question 13

What are Rete Ridges?

Answer 13

Down-growths from the epidermis leading to thick skin

Question 14

What is the structure and function of hair follicles?

Answer 14

Bulb at base which hair protudes from with arrector pili muscle.
Thermoregulation

Question 15

What is the function of a sebaceous gland?

Answer 15

to release sebum into hair follicle for waterproofing

Question 16

What are the 2 types of sweat gland?

Answer 16

Eccrine - Thermoregulation

Apocrine - scent production (axilla and groin)

Question 17

What are the 3 main nervous cells found in skin?

Answer 17

Pacinian corpuscle - Deep pressure/vibrations
Meissners corpuscle - Light touch
Ruffini corpuscle - stretching of skin