L19- Skin Flashcards

1
Q

three main layers of the skin

A

epidermis

dermis

hypodermis

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2
Q

layers of the epidermis from outer layer inwards

A

Cats Gather Suspciously Boldly

  • stratum corneum
  • stratum granulosum
  • st. spinosum
  • st. basale
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3
Q

what structures are found in the dermis

A

hair follicles

arrector pili muscle

sweat glands

sebaceous gland

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4
Q

what type of tissue is the dermis

A

irregular dense connective tissue

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5
Q

thickness of hypodermis varies in

A

ifferent regions of the body and can vary considerably between different people

Thickness plays an important role in distinguishing between males and females

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6
Q

hypodermis in men

A

hypodermis is thickest in the abdomen and shoulders

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7
Q

hypodermis in women

A

thickest in the hips, thighs, and buttocks

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8
Q

hypodermis is the

A

lowest layer of the skin

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9
Q

hypodermis also known as

A

subcutaneous layer

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10
Q

structure of hypodermis

A
  • Mainly contains adipose tissue

• Loose connective tissue – fibroblasts/ macrophages/fibres

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11
Q

function of hypodermis

A
  • energy store- generates heat
  • insulator for udnelryign muscl eheat gen
  • shock absorber
  • conencts skin to underlying muscle and bone
  • makes hormones
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12
Q

dermis located

A

between epidermis and hypodermis

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13
Q
A
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14
Q

structure of dermis

A

Three layers
• Papillary - upper

  • Reticular - lower
  • Dermal papillae – interdigitating
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15
Q

dermis shows…

A

vairbale thickness

0.6 mm on eyelid; 3 mm on hands/feet

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16
Q

function of dermis

A

• Contains hairs and sweat glands - thermoregulation • Contains sensory structures – special senses - touch • Gives structure to skin and so body shape

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17
Q

epidermis location

A

Outermost layer made of epithelial cells (keratinocytes)

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18
Q

structure of epidermis

A
  • Four layers of cells (thin skin)
  • Five layers (thick skin)
  • Held together (laterally) by adherens junctions • Some terminal nerve endings
  • NO blood vessels
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19
Q

function of epdiermis

A
  • Prevents water loss
  • Prevents entry to bacteria and parasites
  • Special cells that present pathogens to immune cells • Synthesis of keratin
  • Prevents underlying tissue loss due to abrasion
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20
Q

stratum corneum

A

Outermost layer made of squames (dead keratinocytes)

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21
Q

stratum corenum on paalms and soles of feet

A

thickest- prone to injury- continously shed

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22
Q

strautum lucidum is

A

transparent

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23
Q

where is stratum lucidum found

A

palms and soles

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24
Q

stratum granulosum

A
  • stratified squamous epithelium
  • lamellar granules
  • tonofibrils
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25
Q

lamellar granules

A

filament-associated proteins that assemble keratin fibrils and secrete it

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26
Q

tonofibrils

A

bundles of keratin filaments and keratohyalin granules- made by lamellar bodies

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27
Q

stratum spinosum

A

3 layers of cubodial epithelium (held together by desmosomes)

  • producers of lamellar bodies
  • first time golgi apparatus appears
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28
Q

lamellar bodies

A

keratin factories

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29
Q

stratum basale

A

Tall columnar epithelial cells

Constantly renew keratinocytes by cell division

As daughter cells differentiate they move away from the epidermis-dermis junction

These make keratin filaments (tonofilaments) They lose their ability to divide

Also home to the melanocytes – produce melanin

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30
Q

ketatinocytes synthesise

A

keratins that cotnribute to the strength of the epidermis

(keratin- main constituents of hair and nail, and animal horns)

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31
Q

normla transit tiem of keratinocytes from basale to stratum conreum

A

28-40 days

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32
Q

in psoriasis

A

transit time is reduced, such that stratum corneum is

produced in abundance as silvery scales every 2-3 days

33
Q

hyperkeratosis

A

too much keratin put on the surface of skin (especially on the hands and feet)

34
Q

main cell found in epidermis

A

keratinocyte

35
Q

other cells in epidermis

A

melanocytes

langerhans

merkel cells

36
Q

how many melanocytes in epidermis

A

1:8 of basal layer of epidermis

37
Q

melanocytes function

A

produce melanin, the main pigment that gives the skin its

colour

38
Q

langerhans function

A

highly specialised capacity to present antigens to
T lymphocytes mediate immune reactions e.g. in allergic contact dermatiti

39
Q

merkel cells

A

mechanoreceptor cells associated with sensory nerve

endings.

40
Q

merkel cells acoount for approx ……. cells in the epidermis

A

6-10%

41
Q

four main types of skin

A
  1. hairy 2. non-hairy 3. Thin 4. Thick
42
Q

hairy skin tends to be

A

thin skin

43
Q

non hairy skin tends to be

A

thick skin

44
Q

expection to the hairy/non-hairy/thin/ thick skin rule

A

the lips, back of the ear, some areas of the external genitalia

45
Q

location of nonhairy (thick) skin

A
  • Palmar surface of hand
  • Plantar surface of the foot
  • Area between fingers and toes (webs)
46
Q

structure of non hairy thick skin

A

NO hair, arrector pili muscles, no sebaceous glands • Thicker strata corneum
• Thinner dermis
• Increased density of mechanoreceptors

47
Q

function of non- hairy thick skin

A
  • Prevent tissue loss due to abrasion
  • Increased friction between skin and surfaces • Increased sensation
48
Q

skin can be classified based on its reaction to ultrabioloit radiation

A
49
Q

differences between thick (non-hairy) and thin (hairy skin)

A
50
Q

thick skin has deep

A

Rete ridges and extended dermal papillae

51
Q

thin (non-hairy) skin has less

A

keratin (stratum corneum narrower) and fewer dermal papillae

52
Q

skin appendages

A

skin associated sturctures that serve a particular function

53
Q

name some skin appendages

A

hairs

arrector pili

sebaceous glands

sweat glands

nails

54
Q

how many types of ahirs

A

3

55
Q

name the 3 types of hair

A
  1. langugo
  2. vellus
  3. terminal
56
Q

lanugo

A

covers the developing fetus (sometimes seen at birth)

57
Q

vellus

A

replaces lanugo
• Short,thin,lightcolouredandsoft(not

connected to sebaceous gland)

58
Q

terminal

A

head (scalp and eyebrows, nasal passage), axillae, external genital region

• Long, wide, dark coloured and coarse

59
Q

how is terminal hair produced

A

• Produced by the actions of testosterone

60
Q

hair function (4)

A

thermoregulation

sexual attraction

sensation

protection

61
Q

hair lays flat when

A

body temperature is within normal range or elevated

62
Q

hair stands erect when

A

body temperature is lower than normal range

63
Q

how do hairs stand erect

A

Arrector pili muscle contracts when stimulated by sympathetic nervous system

64
Q

hair and sexual attraction

A
  • Hair style can be alluring!
  • Apocrine sweat glands secrete oils (pheromones) that attract the opposite sex
  • Hairs trap these oils and accentuate their pungency
65
Q

hair and sensation

A

Hairs have sensory nerve endings within the bulb:

Air movement, physical interaction, vibrations transmitted to the bulb sensed and

66
Q

hair and protection

A
  • Eyelashes and nasal hair prevent dust and pathogens from entering the body
  • Eyebrows reduce the amount of light and sweat from entering the eyes
67
Q

arrector pili muscle consist of

A

smooth muscle fibres attached to papillary region of the dermis (origin) and hair bulb (insertion)

68
Q

arrector pili muscle may also induce

A

sebum release from sebaceous gland

69
Q

name 7 mechanoreceptors in the skin

A

end bulb

free nerve endings

tactile discs

meissner corpuscle

pacinina corpusle

rufinnis corpuslce

root hair plexus

70
Q

end bulbs

A

thermoreceptors

71
Q

free nerve endings

A

have nociceptors- register pain

72
Q

tactile disc

A

senses touch, pressure and texture (Merkel in non-hairy skin); Meissner in hairy skin)

73
Q

meissner corpuscle

A

tapping and flicker movements detected

74
Q

pacinian corpuscle

A

vibration

75
Q

ruffinis corpuscle

A

joint movements and tissue stretch

76
Q

root hair plexus

A

vibrations in the hair shaft

77
Q

location of nails

A

distal surfaces of phalanges (fingers and toes)

78
Q

structure of nails

A

Consists solely of alpha keratin

79
Q

gross structure of nail

A