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Flashcards in Intro to Derm Deck (33):
1

true/false - skin is the largest organ in the body

true

2

what sort of structures does skin contain

adnexal (skin associated) structures - eg hair, nails, glands, sensory structures

3

from the outside to inside what are the three layers

1. epidermis
2. dermis
3. hypodermis (subcutis)

4

what is structure and function of the the sub cutis layer

fat energy store, fibrous bands anchor skin to fascia, insulation

5

what is the structure of the dermis layer

collagen and elastin matrix with mucopolysaccharide gel - fibroblasts, dermal dendritis cells and macrophages

6

what is the structure of the epidermis

5 layers (in-out)
1. stratum basale
2. stratum spinosum
3. straum granulosum
4. stratum lucidum
5. stratum corneum

7

what are the three main cell types in the epidermis

1. keratinocytes (skin cells)
2. melanocytes (pigment-producing cells)
3. langerhans cells (immune cells)

8

what is the role of langerhans cells

process antigens and migrate to lymph nodes to induce an immune response

9

what is the role of melanocytes

make melanosomes (collections of melanin) - excreted and phagocytosis into keratinocytes where they sit above the nucleus

10

how does the epidermis get its nutrients

through diffusion as it is a-vascular

11

what occurs at the stratum basale

cells divide by mitosis and some of the newly formed cells become the cells of the more superficial strata

12

what occurs at the stratum spinosum

keratin fibres and lamellar bodies accumulate

13

what occurs at the stratum granulosum

keratinohyalin and a hard protein envelope form - lamellar bodies release lipids - cells die

14

what occurs at the stratum lucidum

dead cells lie within dispersed heratohyalin

15

what occurs in the stratum corneum

dead cells with a hard protein envelope - cells contain keratin and are surrounded by lipids - cells slough off

16

how would a melanoma at the nail matrix present

a dark strip going along the nail from matrix to hyponychium

17

what are the three stages in the hair cycle

1. anagen
2. catagen
3. telogen

18

what is the anagen stage

active growing stage - 80-90% of hair

19

what is the catagen stage

2-3 week phase where growth stops/follicles shrink - 1-3% hair

20

what is the telogen stage

resting phase for 1-4 months - up to 10% of hair in a normal scalp

21

what are the functions go skin

1. thermoregulation
2. skin immune system
3. barrier
4. sensation
5. vit D synthesis
6. interpersonal communication

22

how does the skin thermoregulate

- insulation, heat transfer

23

how is the skin part of the immune system

innate - eg sweat, non-pathogen specific mechanism

adaptive - antigen presenting cells, antibody production

24

how is the skin a barrier

protects against mechanical, chemical, microorganisms and UV light

keeps in water and electrolytes, macromolecules

25

what sensations does the skin provide

temperature, touch and pain

26

how does the skin synthesise vitamin D

UV light on the skin converts 7-dehydrocholesterol into cholecalciferol

27

in what way does the skin allow interpersonal communication

physical appearance, smell, self-identity - makeup, tattoos, etc

28

what percentage of the population is affected by skin disease

22-30% - population affected:
- 15% of consultation in GP
- 6% hospital referrals

29

what percentage of the affected population have skin cancer/lesions

50%

30

what are external causes of skin disease

temperature, UV, chemical (allergen or irritant), infection, trauma

31

what are internal cases of skin disease

systemic, disease, genetics, drugs, infection

32

what are examples of skin conditions from external causes

1. photosensitivity (light)
2. cold injury (frostbite, chilblains)
3. skin necrosis
4. cold urticaria (wheals)
5. trauma (dermatitis artefacta)

33

what are examples of skin conditions from internal causes

1.