Wk4 Histology Of Skin

Question 1

What are the functions of skin?

Answer 1

Protection - physical barrier
Sensation - pain
Metabolic junctions
Thermoregulation

Question 2

Where does a tattoo sit?

Answer 2

Goes through epidermis into dermis layer as new cells would push out tattoo ink

Question 3

what are the 3 main layers of skin?

Answer 3

Epidermis - epithelial
Connective tissue
Hyperdermis

Question 4

What is the epidermis?

Answer 4

• Keratinised (durability from super strong protein) stratified (more than one layer) squamous (top fat layer) epithelium
• Mostly filled with Keratinocytes (90%)
• Four or Five (thin/thick skin) discrete layers
• Cuboidal cells at the basal layer (bottom layer) (stratum basale)

Question 5

What is the basal layer?

Answer 5

• Cuboidalcellsatthebasallayer
• most deep layer
• sat on the basement membrane
• mitosis occurs to replenish above layers
• melanocytes present

Question 6

What is the stratum spinosum / prickle layer?

Answer 6

• 8-10celllayers
• connected by desmosomes
• gives prickly appearance on dehydration
• produces cytokeratin
- can only see them through dehydration process

Question 7

What is the stratum granulosum / granular layer?

Answer 7

• 3-5 cell layers (gets thinner as you go up)
• become squamous cells
• granules=keratohyalin
• Stain deeply with H&E

Question 8

What is stratum lucidum?

Answer 8

Layer between stratum granulosum and corneum

Only present in thick skin

Question 9

What is stratum corneum / cornfied layer made up of?

Answer 9

• no nuclei or cytoplasm

- squams: packed full of heratin

Question 10

What are other cells of the epidermis?

Answer 10

• Melanocytes(stratumbasale)-melanin,UV protection, pigment
• Merkel cell (stratum basale)- associated with free nerve endings, sensory- light touch
• Langerhan’s(all layers and dermis)- immunecell

Question 11

What is the dermis/reticular layer?

Answer 11

• Reticular layer- dense irregular collagenous tissue- more collagen
• Elastin present throughout dermis
• This elastic reduces with age

Question 12

what neurovascular supply does the dermis have?

Answer 12

• Epidermis- no vasculature
• demis- complex of vessels present
• subpapillary and cutaneous plexus with shunting vessels between
• important in thermoregulation
• controlled by the ANS

Question 13

Where is hair found?

Answer 13

• hairs are only found on thin skin: thick skin has an extra layer bâchage they dont have hairs on spacious glands ( attached to hair follicles normally which secrete oily substance substance called cebum)

Question 14

What is hair made of?

Answer 14

• sebaceous glands secrete oily sebum on upper part of hair follicle
• some regions sebaceous glands are numerous and found independent
• arrector pili muscle- innervated by sympathetic nervous system

Question 15

What glands affect skin?

Answer 15

Sweat glands
• are found in the superficial hypodermis
• watery fluid
• Sebaceous glands attached to hair follicles
• secrete sebum

Question 16

Disorders of the epidermal components

Answer 16

Psoriasis: abnormal epidermal growth and differentiation Malignant melanoma: malignant growth of melanocytes
Vitiligo: Autoimmune destruction of melanocytes
Allergic contact dermatitis: mediated by Langerhans cells

Question 17

Dermatitus summary

Answer 17

Inflammation of the skin
what causes the condition? 
Environment - Atopic dermatitis 
Chemical - contact dermatitis 
Sebum – Seborrheic dermatitis