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DermJaz > Physiology > Flashcards

Physiology Flashcards

(113 cards)

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1
Q

Embryologically the epidermis comes from the ____derm

A

Ectoderm

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2
Q

Embryologically the dermis comes from the ____derm

A

Mesoderm

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3
Q

Embryologically melanocytes comes from ______

A

Neural crest cells

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4
Q

The skin is fully developed at wk __ gestation

A

Week 26

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5
Q

At 4wks gestation the components of the skin are :

A

Periderm, basal layer, dermis (corium)

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6
Q

At 16wks gestation the ____ migrate from ____ and the layers of the skin =

A

Melanocytes migrate from the neural crest

Keratin, granular, prickle cell, basal and dermis

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7
Q

The epidermis is ________ epithelium.

A

Stratified squamous

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8
Q

____ make up 95% of the epidermis

A

Keratinocytes

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9
Q

The prickles in the prickle cell layer are _____

A

Lots of desmosomes

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10
Q

The basal cell layer is ____ for rigidity

A

Undulating

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11
Q

Takes keratinocytes ____ to get from basement membrane until they are shed from the keratin layer

A

28 days normally

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12
Q

Basal cell layer : usually ____ thick
Shape of cells = ________
Contains lots of _______

A

1 cell thick
Small cuboidal cells
Lots of Intermediate filaments (keratin)

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13
Q

Prickle cell layer: shape of cells =

Lots of _____ connecting to _____

A

Larger polyhedral cells

Lots of desmosomes connecting to intermediate filaments

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14
Q

Granular layer: ____ layers of cells = thin/thick layer
Shape of cells =
Contain ___ granules which contain ___ + _____
____ secreted from keratinocytes release _____ => high ____ content
Origin of ____ and _____ are lost here

A

2-3 layers - thin layer
Flattened cells
Keratinohyalin granules contains structural filaggrin and involucrin proteins
Lamellar/Odland bodies release lipids => high lipid content
Cornified envelope origin, cell nuclei lost

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15
Q

Keratin layer- composed of ____ that overlap and have no ____
Other name =
80% ____+____
___ from ____ glues keratin together

A

Corneocytes with no nuclei
Cornified envelope
80% keratin and filaggrin
Lamellar bodies produce FAs

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16
Q

The cells that make up the epidermis =

A

Keratinocytes (95%) melanocytes ( basal and suprabasal) langerhans (suprabasal) merkel cells (basal)

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17
Q

Melanocytes are present in _____ layers

A

Basal layer and above

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18
Q

Melanocytes are ____ cells that produce _____

A

Dendritic cells

UV protection pigment

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19
Q

Melanocytes - organelle that is transferred via dendrites to adjacent keratinocytes, synthesise store and transport _____

A

Melanosomes

Melanin

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20
Q

Melanocytes convert ____ to _____

A

Tyrosine to melanin

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21
Q

Melanin comes in two forms ____ and ____ (give the colour of pigmentation they each give to skin)

A

Eu (brown/black)

Phaeo ( yellow/red)

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22
Q

Melanin forms a cap over the nucleus to protect ___ in the ____ cells and stopping it ___

A

Protects DNA in basal cells and stops it crosslinking

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23
Q

Langerhans originate from ____

A

Mesenchyme - from bone marrow

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24
Q

Langerhans cells are found in the ___ layer, ___ and ____

A

Prickle cell layer, dermis and lymph nodes

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25
Function of Langerhans cells in the skin
APCs - take antigens from skin to lymph nodes- dendritic cells
26
Only cells to contain birbeck granules (racquet shaped)
Langerhans cells
27
Lamellar bodies are ___ shaped
Racquet
28
Merkel cells are found in ____ layer between ___ and _____ | Function =
Basal cell layer between keratinocytes and nerve fibres | Mechanoreceptors
29
Pigmentation in pilosebaceous is due to ____ above the ____
Melanocytes above dermal papilla
30
90% of hairs are in this phase of growth | It takes ____
Anagen - growing phase | 3-7 years
31
10% of hairs are in this phase of growth | Takes _____
Catagen - involuting | 3-4 wks
32
<1% of hairs are in this phase of growth | Occurs in____ hairs per day
Telogen | Resting/ shedding - 50-100 hairs a day
33
Hair and nails are both composed of ____
Specialised keratin
34
Underneath nail plate lies ___ proximally and _____ distally
``` Nail matrix proximally ( similar to hair bulb) Nail bed (CT) ```
35
Functions of DEJ
Epithelial-mesenchymal interactions - support, anchorage, adhesion, growth and differentiation of epidermal cells Semi permeable membrane
36
Contents of the dermis
Collagen, elastin, ground substance, blood vessels, lymphatics, nerves, cells
37
Cells found in the dermis
Mostly fibroblasts (=>collagen) macrophages, mast cells, lymphocytes, Langerhans
38
Ground substance in dermis is composed of
Mucopolysaccharides and glycosaminoglycans
39
Blood vessels in dermis - supply is > than metabolic needs | Organised in ______ that ____and don't/do enter the epidermis
Supply > metabolic needs | Horizontal plexuses branch up and stop at DEJ along with lymphatics
40
Pressure sensors deep in dermis
Pacinian corpuscles
41
Very sensitive vibration sensors in superficial dermis
Meissners corpuscles
42
3 types of skin glands
Sebaceous Apocrine sweat Eccrine sweat
43
Skin glands that are hormone sensitive and cause acne if blocked
Sebaceous
44
Sebaceous glands are _____ distributed. Largest are found on __,___+___
Widely distributed | Face back chest
45
Function of sebaceous glands
Control moisture loss | Bacterial and fungal infection protection
46
Skin glands that produce sebum and mainly open up onto hair follicles
Sebaceous
47
Components of sebum
Squalene, wax esters, triglycerides, FFAs
48
Skin glands that are part of the pilosebaceous unit and found in axils and perineum
Apocrine sweat glands
49
Androgen dependent glands that secrete oily fluid (odorous after bacterial decomposition)
Apocrine sweat gland
50
Locations of eccrine sweat glands
Whole skin surface - especially palms, soles and axillae
51
Eccrine sweat glands have a ___ nerve supply | Stimulated by __,___+___
Sympathetic cholinergic | Mental, thermal and gustatory stimulation
52
sebaceous glands are ___ distributed and are largest on the __+__+__
widely distributed | face, back and chest
53
skin glands that produce sebum | they mainly open onto _____
sebaceous | hair follicle
54
functions of sebaceous glands
control moisture loss | bac and fungal infection protection
55
skin gland that is part of pilosebaceous unit and found in axillae and perineum
apocrine sweat glands
56
sebum components =
squalene, wax esters, triglycerides, FFAs
57
apocrine sweat glands are ____ dependent | they produce ___ that becomes odourous after ___
androgen dependent oily fluid bacterial decomposition
58
skin glands that cover the whole skin surface especially palms, soles and axillae
eccrine sweat glands
59
eccrine sweat glands have a ____ nerve supply - stimulated by ___+___+___
sympathetic cholinergic | mental, thermal ad gustatory stimulation
60
functions of eccrine sweat glands = (3)
ultrafiltration (NaCl-HCO3 into hypotonic fluid) cooling by evaporation palms and sole grip
61
2 metabolic functions of the skin
converts cholecalciferol to vit D3 (290-320nm UV) | T4 to T3 conversion
62
Immunological functions of keratinocytes in keratin layer (3) =
sense pathogens and mediate response eg. UV/allergens produce AMPs and directly kill produce cytokines and chemokines to recruit and reg immune cells
63
epidermis contains mainly ___ T cells dermis contains ____ T cells ___ also present
epidermis = CD8+ dermis = CD4+ and 8+ NK also present
64
Th1 cells activate ___ and produce __+__
macrophages | IL2 and IFNgamma
65
Th2 cells produce _+_+_ and help ___ make ___
IL4+5+6 | B cells make Ig
66
CD4+ cells ass with inflammation ___ (psoriasis) ___ (atopic dermatitis) ___ (both)
Th1 Th2 Th17
67
immunological cells in the epidermis
keratinocytes, langerhans, T cells
68
immunological cells in the dermis
dendritic cells, mast cells, macrophages, neutrophils
69
MHC I is present in ___ cells and present __to ___
most cells | endogenous antigens to CD8+
70
MHC II is present in ___ cells and present ___ to ___
APCs | exogenous antigens to CD4+
71
Scale that gives categories of skin tones and tanning patterns Type __ to __
Fitzpatrick scale | I to VI
72
part of dermis that is thin and just below epidermis
papillary dermis
73
part of dermis that has thicker bundles of type I collagen with sweat glands and pilosebaceous units
reticular dermis
74
ECM of dermis is composed of
hyaluronic acid and chondroitin sulfate
75
components of the dermis
type 1+2 collagen matrix elastic fibres ECM
76
persistance of nuclei in keratin layer =
parakeratosis
77
parakeratosis is present in psoriasis where there is ___
high cell turnover
78
acanthosis =
increased thickness of epidermis
79
papillomatosis =
irregular epidermal thickening
80
spongiosis =
oedema fluid between squames appears to increase prominence of intercellular prickles
81
chemicals in skin that mediate itch
``` histamine PGE2 ACh serotonin IL2 kallikrein substance P ```
82
nerve transmission of itch in skin is by
unmyelinated C fibres
83
mediators in the CNS for itch
opiates (endo+exogenous)
84
orange naevi that if irritated causes a wheal =
mast cell naevi
85
something usually inflam/dryness in skin triggers itch = ___ cause of itch eg.s (4)
``` pruritoceptive asteatotic eczema insect bites lichen planus (sometimes ass with hep C) psoriasis ```
86
basis of cause of itch in asteatotic eczema
direct exposure of unmyelinated C fibres in bases of microfissures and inflammatory mediators in skin released
87
type of eczema that is very xerototic => crazy paving/chicken wiring
eczema craquele
88
4 types of causes of itch
pruritoceptive neuropathic neurogenic pyschogenic
89
basis of itch in neuropathic itch
damage of any sort to central/peripheral nerves that causes itch
90
basis of itch in neurogenic itch
no evident damage in CNS but caused by something affecting the CNS receptors
91
examples of causes of neurogenic itch
haematological, paraneoplastic, opiates, kidneys (endogenous opiates), hyperthyroid, PBC
92
non specific anti pruritics =
``` sedative antihistamines emollients antidepressants (doxepin) phototherapy opiate antagonists ondansetron anti-epileptics for some neuropathic ones ```
93
cells in the skin that metabolise vitamin D
keratinocytes
94
growth development of skin follows
Blaschko's lines
95
maceration =
softening and break down of skin due to prolonged moisture exposure
96
``` erythropoeitic protoporphyria = lack of __ leading to __ build up presents at__ (age) with __ ```
ferrochelatase protoporphyrin IX early childhood discomfort, itch/tingling in sun
97
most common sweat gland on the face =
eccrine
98
acute intermittent porphyria is due to the reduced function of ___ leads to ___ in many tissues
porphobilinogen deaminase | acute neurotoxic reaction
99
Odland bodies are found in which epidermal layer
granular
100
it takes ___ days for cells to migrate from basal to keratin layer
28 days
101
Pressure sensation corpuscles
Pacinian
102
Vibration sensation corpuscles
Meissner's
103
tuberous sclerosis mode of inheritance =
auto dom
104
type 1-4 HPV =
warts
105
type 16 + 18 HPV =
cervical cancer
106
type 6 and 11 HPV =
genital warts
107
__ more likely than ointments to cause contact sensitisation
cream
108
___g of ointment for overall coverage
roughly 30g
109
medial/lateral malleolus ulcers are likely to be __ in origin
venous
110
cancer that can develop on skin ulcers
squamous cell ca
111
Breslow thickness =
depth from granular layer to deepest melanoma cell
112
SCALP layers =
``` Skin CT Aponeurosis Loose CT Periosteum ```
113
sebaceous cyst has an obvious ___ on examination
punctum

DermJaz (9 decks)

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