WK 1- Skin, Hair and Nails Flashcards Preview

SSS > WK 1- Skin, Hair and Nails > Flashcards

Flashcards in WK 1- Skin, Hair and Nails Deck (70):
1

What are some functions of the skin

-Mechanical barrier
-Chemical barrier
-Defence against micro-organisms
-Immunological barrier
-Endocrine organ
-Defence against UV light
-Thermoregulation
-Sensory organ

2

What are the 5 main layers of the epidermis

Moving from top layer to bottom layer
5. Stratum Corneum, 4. Stratum Lucidum, 3. Stratum Granulosum
2. Stratum Spinosum, 1. Stratum Germinativum/basale

3

What is the most common cell of the epidermis

Keratinocyte

4

How thick is the epidermis in the face vs feet
-why is there a change

Approximately 0.1 (face) to 1mm thick (sole of feet)
-Thicker in feet to provide more protection, thinner in face to allow for mobility and sensation

5

What are the 3 non-keratinocyte cells of the epidermis

1. Melanocytes, 2. Langerhans cells, 3. Merkel Cells

6

What is the role of melanocytes

-Melanocytes are pigment cells and provide colour to the skin/hair/eyes
-Melanocytes screen out UV radiation
-All people have the same amount of melanocytes though darker skinned individuals the melanocytes produce more melanaomes, which are broken down less rapidly then caucasoids people

7

Where are melanocytes found and how is melanin transferred

located in the stratum basale, dermis and hair follicles→ most numerous on face and exposed areas of skin
-melanin is contained in melanosomes and then transferred to keratinocytes via dendritic processes

8

What is the role of langerhans cells

Langerhans cells (aka Ag presenting cells) have long dendritic processes that radiate throughout the epidermis- collect Ag- and then migrate through the epidermis and dermis into the lymph nodes where they present to T cells

9

What is the role of Merkel Cells

These are sensory mechanoreceptors--> located in stratum basale but only in thick skin
-closely associated with free nerve endings of cutaneous nerves

10

What is the dermis- what is it composed of

Layer below epidermis that is made from tough supportive connective tissue matrix predominately made of collagen
-elastic connective tissue is the other main type of fibrous connective tissue in the dermis and accounts for 4% dry weight of dermis
-returns skin to normal configuration after stretching

11

What are the layers of the dermis

Reticular (thicker lower layer) and Papillary (thinner upper layer)

12

What are the 4 cells in the dermis

Fibroblasts: synthesis and degradation of CT
Macrophages: phagocytic cells
Mast cells: secretory cells
Lymphocytes: small number collect around blood vessels in normal skin

13

What is the hypodermis- what is it composed of

Subcutaneous tissue underlying the dermis
-composed of adipose cells

14

What is the role of the hypodermis

-aid in insulating the body and allow mobility

15

What are the main sensory receptors of the skin

1. free nerve endings (merkel cells) that allow you to determine pressure on skin→ signals can be relayed to nerve fibres
2. Encapsulated receptors→ pacinian and meissners corpuscle
3. Pertichrial free nerve endings→ sit at the bottom of hair cells and relay touch

16

What are the 3 types of glands in the skin

Sebaceous glands, Aporcrine glands and Eccrine glands

17

What is the function of sebaceous glands

-greatest density on face and scalp- associated with hair follicles
-release sebum

18

What is sebum- what canal is it secreted through

a complex mixture of lipids and secreted onto the skin through the pilosebaceous canal
-sebum has an antibacterial and antifungal action and contributes to normal barrier function of skin

19

When are sebaceous glands most active - what is the connection to acne

sebaceous gland activity is high at birth but declines to almost nothing between 2 and 6 years
-between 7 and 20 sebum production is high and then will decline at the age of 20
-males on average have higher rates than females meaning males have higher rates of acne

20

What is the function of eccrine sweat glands

-release sweat, least abundant on the back

21

What is the function of apocrine sweat glands

-large gland that discharge into hair follicles rather than directly onto the surface (unlike sebaceous glands)
-no odor when first secreted but produces pheromones

22

What is the hyponychium

white area at tip of nail that prevents bacteria entering the nail bed

23

What is the onychocorneal band

distal, white band that marks the most distal firm attachment of the nail plate to the nail bed

24

How long do fingernails take to completely regenerate

12-18 months

25

What are the 3 stages of the hair cycle

Anagen, catagen and telogen

26

What occurs in anagen/how long does it last

growing phase→ follicle penetrates deeply into the hypodermis and keratinocytes in the follicular bulb proliferate to form the hair shaft and melanocytes responsible for the pigmentation of the hair are dispersed among these keratinocytes
-lasts between 2-6 years

27

What occurs in catagen

the keratinocytes and melanocytes undergo programmed death
-lasts less than 2 weeks

28

What occurs in telogen

resting stage, telogen hair has a club shaped proximal end
-lasts around 3 months

29

What is glabrous skin

glabrous skin includes the palms, soles and portions of the genitalia -> no hair follicles

30

What is nikolsky sign

shearing stress on the skin causes separation of the skin along a horizontal plane→ results in traumatic bulla and occurs in fragile skin (autoimmune)

31

What is koebner phenomenon

aka isomorphic phenomenon localisation of a non-infective skin disorder to area of trauma eg. Psoriasis, atopic dermatitis

32

What is dariers sign

rubbing of an area of mastocytosis (bunch of mast cells sitting together) causes an intensive uriticarial reaction

33

What is an abscess

Is collection of pus in a cavity greater then 1cm in diameter

34

What is angioedema

Diffuse swelling of oedema which extends to the subcutaneous tissue

35

What is a bulla

Is a circumscribed elevation of skin over 0.5 cm and containing fluid -eg. Impetigo

36

What is a burrow

Is a linear of curvilinear papule caused by a burrowing mite e.g. scabies , arrows point to scabies

37

What does central clearing mean

Rash with a normal central area

38

What is a keloid

Very raised and erythematous scar

39

What is a comedone

Is a plug of keratin and sebum wedged in a dilate pilosebaceous orifice. Open comedones are blackheads. The follicle opening of a closed comedone is nearly closed over by skin so it looks like a pinhead sized , ivory coloured papule

40

What is dysaesthesia

Tingling, burning, numbness

41

What is ecchymosis

A larger extravasations of blood into the skin

42

What is erythroderma

Rash involving at least 90% of skin surface

43

What is is eschar

Thick crust over an ulcer or erosion

44

What is excoriation

Superficial loss of epidermis (ulcer/erosion) from scratching or picking, therefore often linear and covered by crust eg. Scabies or prurigo

45

What is impetiginised

Covered in crust, pustules often weeping

46

What is lichenification

Thickening of epidermis usually due to friction

47

What is livedo

Purple lace-like or reticulated lesion usually on lower legs

48

What is keratosis

Is a horn like thickening of the skin e.g. solar keratosis

49

What is a macule

Small flat lesion of altered colour or texture
Eg. Lentigo simplex

50

What is a nodule

Raised firm ovoid lesion greater than 0.5cm in width and depth
eg. Nodular keloid scar

51

What is a micropapule

Raised lesion of 1-2mm in diameter

52

What is a papule

Small raised solid lesion less than 0.5mm
eg. Molluscum contagiosum
-can be described by their surface contours

53

What is a papulosquamous

Raised papules on a background of scale and redness

54

What is a plaque

Large raised lesion greater than 2cm in diameter but without substantial depth eg. psoriasis

55

What is purpura

Describes a large macule or papule of blood in the skin. These do not blanch if a glass slide is pushed against them.eg Suction injury and further left Henoch-Schonlein purpura

56

What is a papilloma

Nipple like mass projecting from the skin e.g. a skin tag

57

What is petechiae

Are pinhead sized macules of blood in the skin e.g. Meningococcal disease

58

What does reticulated mean

lace like

59

What is a sinus

Cavity or channel which permits the escape of fluid or pus.eg Pilonidal sinus

60

What is a stria

Streak like, linear, atrophic, pink, purple or white lesion of the skin due to changes in the connective tissue

61

What does serpiginous mean

Edge of lesion is wavy

62

What does targetoid mean

Rash that looks like a bulls eye

63

What is Telangiectasis

Erythematous, fine linear lesion composed of capillaries produced by telangiectasia- visible dilastion of a small blood vessel
eg. Spider Angioma

64

What is a tumour

Enlargement of the tissues by normal or pathological material or cells that form a mass more then 1 cm in diameter

65

What is an ulcer

Is an area of the skin where the whole of the epidermis and at least part of the dermis has been lost. e.g. SCC

66

What does verrucous mean

Very hyperkeratotic- similar to a wart

67

What is a vesicle

Small fluid filled lesion that is less than 0.5mm in diameter eg. Chicken pox

68

What does variegated mean

Multi-coloured

69

What is a wheal

Is an elevated white compressible, short-lived area produced
by dermal oedema. It is often surrounded by red axon
mediated flare

70

What does sclerotic mean

scar like