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Flashcards in Basic Science Deck (42):
1

3 embryological structures that form the skin

mesoderm- dermis
ectoderm- epidermis
neural crest- melanocytes

2

At 4 weeks- 3 layers of the skin

prickle cell layer, basal cell layer, dermis

3

All the layers of the epidermis (4/5)

stratum corneum, (stratum lucidum), stratum granulosum. stratum spinosum, stratum basale

4

keratin layer cells

corneocytes (flat and no nucleus), keratin, desquamation

5

granular layer cells

keratinisation (cells die), keratohyalin, lamellar bodies release lipids, flat and spindle shaped

6

stratum lucidum cells

thick skin
dense flat cells filled with keratin
transparent layer

7

prickle cell layer cells

round and fluid filled
prevent bacteria entering and moisture escaping
polyhedral with desmosomes

8

basal cell layer

mitosis- keratinocyte stem cells
secrete melanin

9

skin epithelium type

stratified squamous

10

journey of melanocytes

basal layer to covering keratinocytes

11

how melanin is formed

tyrosine ---melanosomes---> melanin (eumelanin and pheomelanin)

12

Langerhan cells

APCs in prickle cell layer, dermis and lymph
birbeck granules

13

Merkel cells

mechanoreceptors (touch) in basal layer

14

three phases of hair growth

anagen, catagen, telogen

15

young and old hair

lanugo and vellus

16

structures of the pilosebaceous unit

hair follicle & appendages
- hair shaft
- sebaceous gland
- sebum
- arrector pili
- dermal papilla
- sheaths

17

nail structures

cuticle, lanula, plate
hyponichium, nail bed, nail matrix
posterior nail fold

18

DEJ layers (3)

lamina lucida, lamina densa, sub lamina

19

diseases of the DEJ

EBS/ EBD
pemphigus, dermatitis herpetiformis

20

dermis substances

elastin
collagen (1&3)- produced by fibroblasts
blood, lymph, nerves
mucopolysaccharides, glycoaminoglycans, hyaluronic acid, chondroitin sulphate

21

cells in the dermis

macrophages
mast cells
lymphocytes
langerhans

22

Nerves- dermis

somatic sensory is dermatomes
corpuscles: pacinian= pressure; meissners= vibration
meissners are higher up

23

sebaceous glands

secrete sebum- wax, triglycerides, FFAs
hormones

24

apocrine glands

androgens, oily fluid, scented
go into pilosebaceous unit

25

eccrine glands

sympathetic cholinergic (sweat glands)

26

Functions of the skin

T4-T3
keeps in moisture, heat and protein
vit D metabolism (keratinocytes)

27

Vitamin D metabolism pathway

cholecalciferol (&UV- keratinocytes)
vit D3 (&food)
25-hydroxyvitD (liver)
1,25-hydroxyvitD (kidney)
goes to bone and bowel

28

Layers of dermis

papillary layer- thin, dermal papilla, blood, lymph, nerves
reticular layer- thick, collagen (1), appendage, blood, lymph, fibroblasts

29

hyperkeratosis

increased keratin layer

30

parakeratosis

increased number of nuclei in keratin

31

acanthosis

increased epithelial thickness

32

papillomatosis

irregular epithelial thickening

33

spongiosis

oedema between cells

34

UVB

direct damage
nucleotide excision repair (NER)

35

UVA

indirect oxidative damage
base excision repair (BER)

36

UV light changes to cells in skin

decrease langerhans
increase cytokine and T cells

37

3 cells in forming cancer

proto oncogenes (normal)
oncogenes (defective)
tumour suppressors (negative regulation)

38

p53

stops cell cycle at G1

39

mediators of itch

histamine, PGE2, unmyelinated C fibres

40

4 types of itch

pruritoceptive (trigger)
neuropathic (CNS/PNS)
neurogenic (indirectly affecting CNS)
psychogenic

41

T cells in skin

epidermis- CD8, NK
dermis- CD4 and CD8, NK

42

APCs in skin

dermis and PCL (langerhans)