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Medicine yr1 > FOUND-SKIN > Flashcards

FOUND-SKIN Flashcards

1
Q

what are the functions of skin (5)?

A
  • —>protection (from trauma/ irritants, infection , UV)
  • —>temperature regulation
  • —->sensory detection
  • —->interpersonal detection
  • —->vitamin D production
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2
Q

what is the role of the epidermis?

A

-contains cells that produce pigment and protect immune system

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3
Q

describe the contents of the epidermis.

A
  • stratifies squamous epithelium
  • keratinocytes derived from stem cells
  • 5 LAYERS (Come Lets Get Some Bread)
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4
Q

how is vitamin D produced by the skin and which layer?

A

Vitamin D3 produced by cleavage of 7-dehydro-cholesterol by UVB

-epidermis

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5
Q

what does the epidermis do in response to injury or inflammation?

A

increased proliferation

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6
Q

what is the basal layer of epidermis made up of?

A
  • single layer of cuboidal keratinocytes-produce keratin proteins
  • connected to adjacent cells by desmosomes
  • attached to basement membrane by hemidesmosomes
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7
Q

what do basal cells do?

A

divide to produce new keratinocytes which migrate upwards

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8
Q

what are desmosomes?

A

directly form cell to cell adhesions

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9
Q

what are hemidesmosomes?

A

hemidesmosomes form adhesions between cells and the basement membrane

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10
Q

how long does it take for for the basal layer to shed completely?

A

-4 weeks

  • 2 to reach corneal layer
  • further 2 until shedding
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11
Q

how many cells thick is the spinous layer?

A

5-10

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12
Q

describe the spinous layer

A
  • progressive flattening of cells towards the surface

- desmosomes open to allow the passage of water and individual cell movement

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13
Q

describe the structure of the granular layer.

A
  • 1 to 3 cells thick

- contains keratohyaline granules

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14
Q

what are the roles of the granular layer?

A
  • prepare cells to form the corneal layer

- important layer as barrier to water loss

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15
Q

what does the thickness of the corneal layer depend on?

A

on the site of the layer

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16
Q

what is the structure of the corneal layer?

A
  • semipermeable layer of the cells without nuclei

- dead keratinocytes

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17
Q

what is the role of the corneal layer?

A
  • acts as a barrier

- when barrier function is disrupted function leads to disease

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18
Q

what are the roles of the dermis (5)?

A
  • provide structural support
  • thermoregulation
  • form various elements of the immune system
  • intricate network afferent and efferent nerves for sensation and control of vascular tone
  • mediates itch sensation
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19
Q

what is the structure of the dermis?

A
  • vascular
  • comprised of connective tissue-tensile strength in multiple directions
  • contains sebacous (oil) and sweat glands
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20
Q

what are the different cell types in the dermis?

A
  • macrophages
  • fibroblasts
  • mast cells
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21
Q

where do melanocytes reside and what percentage of cells do they make up here?

A

basal layer of epidermis

10%

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22
Q

what do the numbers of melanocytes depend on?

A

racial skin type

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23
Q

what type of cell is a melanocyte?

A

form of dendritic cell

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24
Q

what do melanocytes do?

A
  • produce melanosome

- melanosome synthesises melanin-absorbs UVB

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25
Q

what is the role of melanin?

A
  • concentrated in basal layer
  • induced by UV
  • absorbs UV
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26
Q

what are the different types of UV and how much damage do they each cause?

A
  • UVC-cannot penetrate skin
  • UVB-penetrates skin-direct energy absorption by DNA-can cause mutations-cancer
  • UVA-penetrates skin more
  • visible light penetrates most
  • these both cause DNA strand breaks/ oxidative damage/ base modification -can cause cancer
27
Q

what is cutaneous immunosurveillance?

A

the immune system within skin (in healthy cells) which can repair much of the damaging effects of light

28
Q

what happens when immunosurveillance fails?

A

greater risk of squamous cell carcinoma

29
Q

where are Langerhans cells predominantly situated?

A

epidermis (spinosum)

30
Q

where are Langerhans cells derived from?

A

bone marrow

31
Q

what is the role of Langerhans cells?

A

antigen processing not antigen presenting

  • important in cutaneous immunosurveillance and contact
  • initiate adaptive immune response
32
Q

where are merkel cells situated?

A

located just above basement membrane (between dermis and epidermis-basale)

33
Q

what is the role of merkel cells?

A

rudimentary touch receptor-mechanoreceptors (pacinian and meissner’s corpuscles)

34
Q

what do merkel cells contain?

A

neuroendocrine peptides with intracytoplasmic granules

35
Q

what are 2 examples of merkel cells?

A
  • pacininan corpuscles-deep dermis

- meissiner’s corpuscle-more superficial dermis

36
Q

which cell is the primary cell of the dermis?

A

fibroblast

37
Q

what are the roles of the fibroblasts?

A
  • produce key components of extracellular matrix

- important in wound healing and scar formation

38
Q

what type of cell is a mast cell and where does it originate from?

A

granulocyte

bone marrow

39
Q

what is the role of a mast cell?

A

role in defence but also involved in allergic reactions

40
Q

what are some other immune cells in the dermis?

A
  • dermal dendritic cells
  • macrophages
  • lymphocytes
  • neutrophils
  • eosinophils
  • plasma cells
  • —->all play role in infection and inflammation
41
Q

what are nails made of?

A

hard keratin

42
Q

where does the nail plate grow from?

A

nail matrix

43
Q

what are the roles of nails?

A
  • protects the fingertip

- provides counter pressure to aid sensation

44
Q

what are hairs made up of?

A

keratin

45
Q

where is hair produced?

A

hair follicles

-follicular unit-also comprises of sebaceous glands and errector pili muscles

46
Q

what are the 2 types of hair?

A
  • terminal (coarse)

- vellus (fine)

47
Q

how does hair grow?

A

in a cycle (grow/ rest/ fall out phases)

48
Q

what are the functions of hair?

A
  • protection
  • sensory (eg cat whiskers)
  • temperature regulation
  • social
49
Q

name 2 hair abnormalities?

A
  • hirsutism-too much hair growth in antigen receptive areas-can be sign of hormone imbalance
  • alopecia areata-immune system switches off hair follicles in specific area-can regrow but random
50
Q

what are the 2 types of sweat glands?

A
  • eccrine

- apocrine

51
Q

what is the role of eccrine glands?

A

sweating allows heat loss

52
Q

what is the role of apocrine glands?

A

sweating may be linked to pheromones-causes body odour

53
Q

what does the density of glands depend on?

A

the site

54
Q

what is a dermatome?

A

area of skin supplied by single nerve

55
Q

what are the 3 hair generation phases?

A

1-TELOGEN- epidermal cells of follicle are forming
-cells of hair matrix divide and are added to the base

2-ANAGEN-hair growth phase

3-CATAGEN-hair falls off the follicle

56
Q

which protein does hair generation involve?

A

alpha keratin

57
Q

what is the role of pacinian corpuscles?

A

deep pressure mechanoreceptor

58
Q

what is the role of meissner’s corpuscle?

A

mechanoreceptors, fine touch

59
Q

what is the role of the end-bulbs of krause?

A

thermoreceptors

60
Q

what is the role of ruffinis end organ?

A

skin stretch

61
Q

what is the role of the sebaceous gland?

A

release sebum into skin and hair via holocrine secretion

62
Q

what are the 5 layers of the epidermis?

A

Come Lets Get Some Bread

1-stratum CORNEUM 
2-stratum LUCIDUM
3-sratum GRANULOSUM 
4-stratum SPINOSUM 
5-stratum BASALE
63
Q

which cell types are in the epidermis?

A
  • dead kertainocytes (s. corneum)
  • lamellar granules (s. granulosum)
  • keratinocyte (s. spinosum)
  • langerhans (s. spinosum)
  • melanocyte (s. basale)
  • merkel cell (s. basale)

Medicine yr1 (55 decks)

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