Skin Structure and Function

Question 1

Name the layers of the skin

Answer 1

Epidermis (outermost)
Dermo-epidermal junction
Dermis
Sub-cutis

Appendages (hair, glands, nails)

Question 2

What is the pilosebaceous unit?

Answer 2

Sebaceous gland draining into the side of a hair follicle

Question 3

What are the layers of the epidermis, from the skin surface down?

Answer 3

Keratin layer
Granular layer
Prickle cell layer
Basal layer

Question 4

Describe the production and loss of keratinocytes in the epidermis

Answer 4

Produced by stem cells in the basal layer

Migrate to prickle cell layer –> granular layer –> keratin layer –> shed

Question 5

How long does the keratinocyte cycle of production and loss take in normal skin?

Answer 5

About 28 days

Question 6

Which condition is associated with increased rate of keratinocyte production and loss?

Answer 6

Psoriasis –> cycle takes about 4 days

Question 7

Name three other cell types found in the epidermis

Answer 7

Melanocytes
Merkel cells
Langerhans cells

Question 8

What do melanocytes do?

Answer 8

Produce melanin to protect the skin from UV radiation

Question 9

Which condition is caused by patches of absent melanocytes?

Answer 9

Vitiligo

Question 10

What are Merkel cells?

Answer 10

Fine touch receptors

Question 11

What are Langerhans cells?

Answer 11

Skin immune cells

Question 12

How are keratinocytes held together in the epidermis?

Answer 12

By desmosomes in the prickle cell layer

Question 13

Which condition results from IgG antibodies against desmosomes?

Answer 13

Bullous pemphigus

Question 14

Where are the antibodies attacking in bullous pemphigoid?

Answer 14

Dermo-epidermal junction

Question 15

What are the two main types of connective tissue in the dermis?

Answer 15

Collagen

Elastin

Question 16

Name some cells that are present in the dermis?

Answer 16

Fibroblasts
Mast cells
Langerhans cells
Macrophages + lymphocytes

Question 17

What do fibroblasts do?

Answer 17

Produce collagen and elastin

Question 18

What results from over proliferation of fibroblasts?

Answer 18

Dermatofibroma (benign)

Question 19

What do mast cells release and what type of rash does it cause?

Answer 19

Histamine

Urticaria

Question 20

Which condition is a disorder of the pilosebaceous unit?

Answer 20

Acne

Question 21

Which protein is important for the skin’s barrier function and which condition is it deficient in?

Answer 21

Filaggrin

–> deficiency in eczema

Question 22

What does hyperkeratosis mean?

Answer 22

Increased thickness of the keratin layer

Question 23

What does parakeratosis mean?

Answer 23

Persistence of nuclei in the keratin layer (normally no nuclei)

Question 24

What does acanthosis mean?

Answer 24

Increased thickening of the epidermis

Question 25

What does spongiosis mean?

Answer 25

Oedema between keratinocytes