Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

RB Y2 Dermatology > Structure and Function of the Skin > Flashcards

Structure and Function of the Skin Flashcards

You may prefer our related Brainscape-certified flashcards:
Dermatology Board Prep flashcards
1
Q

what are the lines of normal skin development called

A

Blaschko’s lines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

epidermis layer

  • what does it arise from
A

stratified squamous that arises from dividing basal keratinocytes

varies at different body sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

rete ridges

A

downward projections of the epidermis into the dermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

name the layers of the epidermis

A

keratin

granular

prickle

basal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

keratin layer of epidermis

A
  • also called stratum corneum
  • Composed of layers of flattened, scale-like cells. Thousands of these dead cells shed from the skin surface every day and are replaced by new ones from deeper layers.
  • Corneocytes – terminally differentiated keratinocyte, are toughened and provide protection to the skin. Compose most of the stratum corneum
  • contains filaggrin, involucrin and keratin (80% keratin and filaggrin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where is teh keratin layer of epidermis thicker

A

areas of increased mechanical pressure eg sole of foot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what does the keratin layer of epidermis provide

A

a tight waterproof barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

granular layer of epidermis

A
  • Consists of 3/4 flattened layers of cells
  • Keratohyalin granules that are the precursor to keratin, producing the keratin layer above.
  • Odland bodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

prickle layer of epidermis

A

contains polyhedral cells with lots of desmosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

basal layer of epidermis

A
  • single layer of cells in conact with dermis
  • cells in the epidermis proliferate from the basal layer - most metabolically active during foetal development
  • contains melanocytes, merkel cells, keratinocytes and langerhans cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

keratinocytes

A
  • can secrete a variety of cytokines in response to tissue injury or certain skin disease. play a role in immune function (innate and adaptive), cutaneous inflammation and tissue repair
  • Produce keratin, which toughens and waterproofs the skin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what can keratinocytes be activated by

A

UV or sensitizers (eg allergic contact dermatitis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

which cell carry out vitamin D metabolism

A

kertatinocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does HPV infection of keratinocytes cause

A

warts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

melanocytes

A

dendritic cells formed in the basal layer and secrete the pigment melanin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

where do melanocytes migrate from

A

neural crest to the epidermis in the first 3 months of foetal development

found above basal layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the function of melanocytes

A

provide DNA protection from UV radiation

  • convert tyrosine to melanin which absorbs light
  • full melanosomes transferred to adjacent keratinocyte via dendrites and form protective cap over nucleus.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are racial differences in skin pigmentation due to

A
  • Found in equal numbers in black and white skin, but vary in melanin production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

vitilgo

A

autoimmune disease with loss of melanocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

nelson’s syndrome

A

excess of melanin stimulating hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

merkel cells

A

found in the basal layer of the epidermis between keratinocytes and nerve fibres

act as mechanoreceptors - numerous on finger tips and oral cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

basement membrane zone

A
  • A structure consisting of collagen, hemidesmosomal proteins, integrins and laminin
  • collectively, they hold the skin together, keeping the epidermis attached to the dermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

dermis

A

contains blood and lymphatic vessels, nerves, muscles, appendages and a variety of immune cells (mast cells and lymphocytes etc)

also contains, type I and III collagen, elastic fibres, ground substaces, fibroblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what cells are involved in collagen synthesis

A

fibroblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

langerhans cells

  • what are they characterised by
A

characterised by the Birbeck granule

26
Q

why does skin sag as one gets older

A

collagen fibres are lost - they provided structure and tensile strength

27
Q

dermographism

A

exaggerated wealing tendency when the skin is stroked

28
Q

what are the 2 layers of the dermis

A

papillary - thin and lies just below epidermis, intertwines with rete ridges

reticular - thicker bundles of type I collagen, contains appendage structures

29
Q

pacinian corpuscles

A

somatic sensory nerves that sense pressure

30
Q

Meissners

A

somatic sensory nerves that sense vibration

31
Q

what is a pilosebaceous unit

A

The structure consisting of hair, hair follicle, arrector pili muscles and sebaceous gland is an epidermal invagination known as a pilosebaceous unit.

32
Q

what causes the pigmentation of hair follicles

A

melanocytes above the dermal papilla

33
Q

what are the 3 types of hair

A

terminal (eg scalp, beard, pubic)

vellus (face of women, prepubertal children)

lanugo (anorexia nervosa and newborns)

34
Q

what are the 3 stages of hair growth

A

anagen = growing

catagen = involuting

telogen= resting

35
Q

what is the telogen phase of hair growth like in humans

A

asynchronous

36
Q

sebaceous skin gland

A

responsible for secreting sebum or grease onto the skin surface (via the hair follicle) and are found in high numbers on scalp and face

hormone sensitive and inactive until puberty

control moisture loss and prevent from fungal infection (maintain skin barrier)

37
Q

apocrine glands

A

scent glands found in the axilla and perineum

are androgen dependent - dont function until puberty

38
Q

eccrine glands

A

sweat glands found on the whole skin surface, except mucosal surfaces

they are most common on the face, palms and soles of feet

39
Q
A

A sebaceous

B apocrine

C eccrine

D = eccrine sweat gland, E = sebaceous gland, F = arrector pilli muscle, G = apocrine sweat gland

40
Q

subcutaneous layer of the skin

A

consists predominantly of adipose tisuse as well as blood vessels and nerves

provides insulation and acts as a fat store

41
Q

name some functions of the skin

A

metabolism and detoxification

thermoregulation

immune defence

communication

sensory

42
Q

describe the skin’s role in vitamin D metabolism

A

UV exposure allows the conversion of 7 dehydro-cholesterol in the skin to vitamin D3 (cholecalciferol)

43
Q

arthus reaction

A

localised type III hypersensitivity

skin testing in type III leads to arthus reaction - localised vasculitis as a result of immune complex deposition

44
Q

compare the growth rate of nails to toe nails

A

nails - 0.1mm day

toe nails are slower

45
Q

are nails or toe nails more commonly affected by disease

A

toes

46
Q

describe nail anatomy

A
47
Q

what are the physiological factors of skin that allow it to act as a barrier

A

low pH (5.5)

low oxygen tension

48
Q

define skin failure

A

Skin failure is defined as loss of normal temperature control with inability to maintain the core body temperature, and failure to prevent percutaneous loss of fluid, electrolytes and protein, with resulting imbalance, and failure of the mechanical barrier to prevent penetration of foreign materials.

49
Q

innate and adaptive immune system in skin

A
  • The innate immune system of the skin comprises neutrophils and macrophages as well as keratinocyte-producing antimicrobial peptides. Expression of these peptides is both constitutive and induced by skin inflammation and they are active against infection and play a role in wound healing
  • Adaptive immune response is slower in onset, results in immunological memory and is mediated by T and B lymphocytes
50
Q

role of keratinocytes in immune protection

A
  • secrete a variety of cytokines in response to tissue injury or certain skin disease
  • produce AMPs which kill pathogens directly
51
Q

role of Langerhans cells in immune protection

A
  • Langerhans cells are a type of dendritic cells (antigen presenting) interspersed with keratinocytes in the basal layer of the epidermis.
  • migrate throughtout the epidermis and dermis and travel via lympahtics to present antigens in lymph nodes - activate T cell response
52
Q

where are Langerhans cells formed

A

bone marrow

53
Q

which T cells are found where in the skin

A
  • T cells (epidermis/dermis), mainly CD8+ T cells found in the epidermis and CD4+ and CD8+ found in the dermis.
54
Q

T cell action

A
  • CD4+ T helper cells
    • TH1 activate macrophages to destroy micro-organisms. Their effector cytokines are IL-2 and IFNg
    • TH2 activate B cells to produce plasma cells which produce antibodies. Their effector cytokines are IL-4, -5 and -6
  • CD8+ T cells
    • Can kill infected cells directly via apoptosis
55
Q

where are T cells produced and where do they mature

A

produced in bone marrow and mature in thymus

56
Q

which T cells are associated with psoriasis and atopic eczema

A
  • CD4+ TH cells associated with inflammation include TH1 (psoriasis), TH2 (atopic dermatitis) & TH17 (psoriasis and atopic dermatitis).
57
Q

what immune cells are found in the dermis

A

macrophages, neutrophils, mast cells, dermal dendritic cells

58
Q

plasmacytoid DC

A
  • DC that are found in inflamed skin, secrete IFN alpha
  • Those who suffer from psoriasis typically exhibit skin lesions where pDCs accumulate
59
Q

which chromosome do MHC molecules occur on

A

6

60
Q

MHC class II cells

A
  • Found only on antigen presenting cells e.g. phagocytes, macrophages, dendritic cells
  • An APC takes up an antigen, processes it and retains a fraction called an epitope on the APC surface.
  • This coupled within an MHC class II molecule mediates antigen presentation.
  • Present to helper T cells – CD4 receptors
61
Q

immunology of psoriasis

A
  • The KC under stress releases factors that stimulate the pDC to produce IFN alpha, and release IL-1 beta, IL-6 and TNF
  • Chemical signals activate the DC, which migrate to skin draining lymph node to present to and activate T cells: TH1 and TH17
  • T cells are attracted to the dermis by chemokines and secrete IL-17 and 22. This stimulates KC proliferation, AMP release and neutrophil-attracting chemokines
  • Dermal fibroblasts become involved
62
Q

immunology of atopic eczema

A
  • Impairment of skin barrier is a key factor:
    • Mutations in the filaggrin gene is associated with severe/early onset disease
    • Decreased AMP, may account for susceptibility to infection
  • It allows access/sensitisation to allergen and promotes colonisation by micro organisms
  • Immunological cells are found in lesions, probably attracted by the stressed keratinocytes

RB Y2 Dermatology (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions