Skin Histology and Pathology

Question 1

What are the functions of the skin?

Answer 1

Prevent fluid loss, Vit D, Thermoregulation, Protection, Sensation, Healing/regeneration, social/sexual

Question 2

What are the layers of the skin?

Answer 2

• Epidermis
• Dermis
• Hypodermis

Question 3

What are the layers of the Epidermis?

Answer 3

• Basale
• Spinosum
• Granulosum
• Corneum

Question 4

What are the cells located in the Basale layer?

Answer 4

• Stem cells
• Transit-amplifying vells
• Post-mitotic
• Merkel cells
• Melaocytes

Question 5

How are the cells of the basale membrane attached to the basement membrane?

Answer 5

• Hemidesmosomes

Question 6

What is the Striatum spinosum layer?

Answer 6

• Has desmosomes to provide resistance to abrasion

- Anchored to intracellular proteins “tonofibrils”

Question 7

Whats in the striatum granulosum?

Answer 7

Cells fills with granules of keratohyaline protein

Secrete waxy, waterproofing substance

Question 8

Whats in the Striatum corenum?

Answer 8

• Flattened, keratin-filled anucleated squames
• In a continous extracellular lipid matrix
• “Barket-wave” pattern

Question 9

What are langehans histiocyes?

Answer 9

• Macrophages of skin

- In striatium spinosum

Question 10

What are the layers of the dermis?

Answer 10

• Papillary dermis

- Reticular dermis

Question 11

Describe the papillary dermis?

Answer 11

• Increase attachment to epidermal “rete ridges”

- Contain capillary loops (Subpapillary plexus)

Question 12

Describe the reticular dermis

Answer 12

• Denser colagen
• Bigger Vessels (Dermal plexus)
• Appendages

Question 13

Whats in the hypodermis?

Answer 13

• Adipose tissue + fibrous septae

Question 14

What are the skin “appendages”

Answer 14

• Pilosebaceous units
• Sweat glands and ducts
• Apocrine glands

Question 15

What are the stages of skin healing?

Answer 15

• Coagulation Phase
  1. Platelets
• Inflammatory phase
  2. Plateletes, Macrophages, Neutrophils
• Migratory phase
  3. Fibroblasts, Epithelial cells, Endothelial cells
• Remodelling phase
  4. Myofibrblasts

Question 16

Whats the difference between primary and seconary intention healing?

Answer 16

Primary = close the wound, healing simply and quick

Secondary = Form lots of granulation tissue takes a long time, gets retracted scar

Question 17

What happens in damaged skin after 3 days?

Answer 17

• Inflammatory exudate established
• Increased macrophage
• Fibrin clot
• Activation of fibroblasts and endothelial cells

Question 18

What happens in damaged skin after 7 days?

Answer 18

• Vascular granulation tissue at base

- Keratinocyte migration and proliferation

Question 19

12 days

Answer 19

• Granulation tissue become mature
• Re-epitheliasation complete
• Stratum corneum reform under scab
• Scab falls off
• Wound contractoon

Question 20

What are the features of mature scar?

Answer 20

• Fibrous scar under epidermis
• Loss of rete ridges
• NO appendages

Question 21

When should you remove sutures?

Answer 21

5-10 days

Question 22

What are the zones of burned skin?

Answer 22

• Zone of coagulation (necrosis)
• Zone of stasis (reduced BF)
• Zone of hyeraemia

Question 23

1st degree burn

Answer 23

Superficial

Question 24

2nd degree burn

Answer 24

Partial thickness (deep/superficial)
- Deep requires skin graft

Question 25

3rd degree

Answer 25

full thickness

Question 26

4th degree

Answer 26

Involve deep structure

Question 27

Actinic keratinosis

Answer 27

• Abnormal basal cells
• Acanthosis = Thickening of epidermis associated with increaswed cell turnover
• Parakeratosis = Nuclei in stratum corneum
• Solar elastosis = Blue pappilary demis from UV

Question 28

Solar kertosis

Answer 28

Dysplasia

• Abnormal basal cells
• Many mitosis
• Poor differentiation
• Precursor to SCC
• Should be treated

Question 29

SCC

Answer 29

• Keratin pearls
• Intercellular bridges
• ## Can become invasive

Question 30

Basal cell carcinoma

Answer 30

• No keratin cells/Intracellular bridges

- Never metastasise