Skin Structure & Function Flashcards

1
Q

Epidermis tissue type

A

Stratified squamous epithelium

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2
Q

Dermis tissue type

A

Connective tissue

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3
Q

Layers of the epidermis

A
Superficial to deep - 
Keratin layer 
Granular layer 
Prickle cell layer 
Basal layer 
(then dermis)
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4
Q

rete ridges

A

downward projections of the epidermis down into the dermis

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5
Q

Blaschko’s lines

A

lines of normal cell development in the skin - not seen normally.
Presence indicates a developmental growth pattern of skin problem

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6
Q

What composes 95% of the epidermis

A

Keratinocytes

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7
Q

Why is there continuous regeneration of the epidermis

A

Keratinocytes migrate from the basement membrane of the epidermis

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8
Q

How long does the process of keratinocyte migration normally take

A

around 28 days

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9
Q

How long does the process of keratinocyte migration take in psoriasis

A

45 days

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10
Q

In what layer of the epidermis can intra-epidermal blistering occur

A

Prickle cell layer -

lots of desmosomes (connections) that are burst apart by hydrostatic pressure

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11
Q

What layer of the epidermis is the origin of the ‘cornified envelope’

A

Upper cells of the granular layer - stratum corneum

lose their nuclei and become surrounded by tough envelope of proteins

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12
Q

what are corneocytes

A

terminally differentiated keratinocytes that are non-nucleated

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13
Q

what common skin complaint affects keratinocytes

A

Warts - HPV 4+11

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14
Q

why are children more susceptible to warts

A

cornified envelope hasn’t formed properly

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15
Q

Other epidermal cells apart from keratinocytes

A

melanocytes
langerhans cells
merkel cells

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16
Q

What are skin appendages

A

hair follicles
sebaceous glands
sweat glands

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17
Q

what are melanocytes

A

melanin-producing neural-crest derived cells

pigment-producing dendritic cells

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18
Q

What layer of epidermis are melanocytes found

A

basal layer

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19
Q

Vitiligo

A

autoimmune disease with loss of melanocytes

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20
Q

Albinism

A

genetic partial loss of pigment production

21
Q

Nelson’s syndrome

A

Clinical sign for presence of a pituitary tumour - melanin stimulating hormone produced in excess by pituitary

22
Q

What layer of epidermis are Langerhan’s cells found in

A

Prickle cell layer (suprabasal)

also dermis and lymph nodes

23
Q

What are Langerhan’s cells

A

main skin resident immune cell

antigen-presenting - pick up antigen in skin and circulate to lymph node

24
Q

Characteristic of Langerhan’s cells

A

Birbeck granules

25
What are merkel cells
mechanoreceptors found in skin (mostly palms and soles) responsible for light touch sensation
26
What layer of epidermis are merkel cells found in
basal layer
27
what are hair follicles also known as
pilosebaceous unit (adjacent sebaceous gland)
28
dermal papillae definition
any small elevation in the dermis that indent the inner surface of the epidermis
29
Label the different parts of the pilosebaceous unit
(be able to do)
30
phases of growth of hair follicles
Anagen = growing (3-7yr) Catagen = involuting (3-4wks) Telogen = resting (shedding) (each day 50-100 <1%)
31
Label the different parts of the nail unit
(be able to do)
32
Hyponychium of the nail
secures the free nail edge
33
Structure of the Dermo-Epidermal junction
From superficial to deep - ``` Hemidesmosomes - at basal cell layer of epidermis Lamina lucida Lamina densa Sub lamina densa zone (then dermis) ```
34
Inherited conditions of the DEJ
Epidermolysis bullosa - mutation of one of the proteins in the DEJ
35
Acquired conditions of the DEJ
Pemphigus Pemphigoid Dermatitis herpetiformis - autoantibodies to proteins in the DEJ
36
What are the different components of the dermis
Cells: fibroblasts, macrophages, mast cells, lymphocytes, Langerhans cells Fibres: collagen, elastin Ground substance: jelly like mass Blood vessels, lymphatics, nerves
37
Role of fibroblasts in dermis
Collagen secretion
38
Role of macrophages in dermis
Antigen presentation
39
Role of Langerhans cells in dermis
Antigen presentation
40
Role of mast cells in dermis
Chemical messengers
41
How do blood vessels in the dermis appear
as horizontal plexuses
42
role of lymphatic vessels in dermis
continual drainage of plasma proteins, extravsculated cells and excess interstitial fluid
43
Specialised nerve receptors in the dermis
Pancinian receptors - pressure receptors (nearer bottom of dermis) Meissners corpuscles - vibration receptors (nearer top of dermis)
44
Different types of skin glands
Sebaceous glands Apocrine glands Eccrine glands
45
What are sebaceous glands
exocrine glands that secrete oily sebum present on face and chest mostly hormone sensitive inactive until puberty
46
What are apocrine glands
develop as part of pilosebaceous unit (coiled side part on histology) found mostly in armpits, areola of nipples androgen dependent sweat glands
47
What are eccrine glands
common sweat gland found throughout skin except mucosal surfaces mostly palms/soles to aid grip
48
Main metabolic roles of skin
vitamin D metabolism | thyroid hormone metabolism (T4 to T3)