Week 1 Flashcards
(93 cards)
1
Q
What is the difference between prevelance and incidence?
A
Prevelance= number of people in the population at any one time that have a particular disease incidence= number of new cases of a disease over a fixed period of time
2
Q
What lines mark the developmental growth pattern of skin? If a condition follows these lines what is it a sign of?
A
Blaschko’s lines
sign of congenital/embryological skin condition
3
Q
What form of epithelium is the epidermis composed of? What are the majority of the cells called?
A
stratified squamous epithelium
keratinocytes
4
Q
Identify the four layers of the epidermis and list them in order
A
Keratin layer
granular layer
prickle cell layer
basal layer
5
Q
How thick is the basal epidermal layer? What shape are the cells? How do the cells of the prickle cell layer differ?
A
One cell thick usually
small cuboidal
larger polyhedral cells with many desmosomes
6
Q
What structural proteins are packed into granular layer cells?
A
Filaggrin and Involucrin
7
Q
What are the cells of the keratin layer of the epidermis called? What makes it suitable to be the most superficial layer? What major organelle is absent?
A
Corneocytes
Tight waterproof layer
nuclei
8
Q
Apart from keratinocytes name three other cells found in the epidermis
A
melanocytes
Langerhans cells
Merkel cells
9
Q
From where do melanocytes originate? What pigment do they produce? What organelles do they possess? what is the function of this pigment?
A
neural crest
melanin
melanosomes
absorbs light
10
Q
What is the function of melanin caps?
A
they cover the nuclei of basal cells to protect their DNA
11
Q
What is Vitiligo?
A
An autoimmune disease causing loss of melanocytes
12
Q
What is Nelson’s syndrome?
A
A disorder where melanin stimulating hormone is produced in excess by the pituitary gland
13
Q
What are Langerhans cells?
A
Dendritic cells which are found in the prickle cell layer and Dermis. they detect antigenic material
14
Q
What are Merkel cells? What causes merkel cell malignancy?
A
Mechanoreceptors of the skin
infection
15
Q
Give another name for a hair follicle
A
pilosebaceous unit
16
Q
What muscle is associated with the pilosebaceous unit?
A
Arrector pili muscle
17
Q
Name the three phases of hair growth
A
Anagen
telogen
catagen
18
Q
What contributes to the pigmentation of hair?
A
Melanin from melanocytes
19
Q
What supplies blood to the hair follicle?
A
Hair Papillae
20
Q
What is the name of hair loss that can occur during periods of systemic stress
A
Telogen effluvium
21
Q
What is the name of autoimmune hair loss?
A
Alopecia areata
22
Q
What do you name the half moon shape of the nails? From what area does the nail grow?
A
lunula
nail matrix
23
Q
What gland is associated with the hair follicle? What does it produce and what is its function?
A
sebaceous glands
sebum- acts as an emollient (Moisturiser)
24
Q
What is the name of the interface between the dermis and epidermis?
A
Dermo-epidermal junction
25
Name two diseases of the dermo-epidermal junction
Bullous pemphigoid
| epidermolysis bullosa
26
What does the dermis consist of?
Connective tissue
| blood vessels, nerves, lymphatics
27
What brings about photoaging?
Exposure to UV light causes loss of collagen and elastic fibres in the dermis
28
What is dermographism?
itchy skin reaction to stroking of skin
29
Name two special sensory nerve receptors of the skin
```
Pacinian corpuscles (Pressure)
Meissner's corpuscles (vibration)
```
30
What is hirsutism?
male pattern hair growth in women due to excess androgens
31
Name the three glands found in the skin
sebaceous
Apocrine
eccrine
32
Eccrine glands and apocrine glands are found in the _________.Apocrine glands are ______ glands of the ______ and __________. Meanwhile eccrine glands are sweat glands which cover the whole body. They are under __________ control
```
Dermis
sweat
axilla
perineum
sympathetic
```
33
The superficial fascia (___________ ______) of _______ connective tissue lies above the deep fascia of ______ connective tissue
subcutaneous fascia
loose
dense
34
Name the four fascia of the upper limb. what about the thigh and the leg?
```
pectoral
brachial
deltoid
antebrachial
fascia lata
crural fascia
```
35
What does the popliteal artery bifurcate into?
anterior tibial and posterior tibial
36
What does the brachial artery bifurcate into?
radial and ulnar
37
What supplies blood to the palms? What drains the palm?
deep and superficial palmar arterial arches
| dorsal venous network and venous arches
38
Name the two main superficial veins of the upper limb and the vein that goes between them in the cubital fossa. Which is lateral and which is medial?
cephalic vein- Lateral
basilic vein- medial
median cubital vein
39
Name two superficial veins of the lower limb
great saphenous
| small saphenous
40
Name the two main veins of the thigh and the three main veins of the leg
```
deep femoral
femoral
anterior tibial
posterior tibial
fibular
```
41
Vitamin D metabolism occurs in the skin. _____________ is converted to Vitamin D3 by ____________ __ light. Furthermore ________ hormone metabolism also occurs in the skin.
Dehydrocholesterol
Ultraviolet B
Thyroid
42
Give another name for the keratin layer of the epidermis
stratum corneum
43
What three attributes do keratinocytes have that make them effective against infection
surface receptors to detect pathogens
Produce AMPs (Antimicrobial Peptides) which directly kill pathogens
Produce cytokines and chemokines
44
Langerhans cells are _________ __________ _____ and are characterised by having a ________ granule
Antigen Presenting cells
| Birbeck
45
What types of T cell are found in the dermis? What about the epidermis?
CD4+ CD8+
| CD4+
46
Which two dendritic cells are found in the dermis?
Dermal DC
| Plasmacytoid DC- produce IFN alpha
47
What are the Hallmarks of Psoriasis?
Inflammatory skin lesions
reversible plaques
1/3 psoriatic arthritis
48
Give three possible environmental causes of psoriasis
```
Koebner's phenomenon- after mild trauma to the skin
bacterial pharyngitis
psychological stress
HIV infection
beta blockers/lithium
```
49
Mutations of the gene for what protein are associated with atopic eczema?
Filaggrin gene
50
What are SPT I and SPT IV?
2 of the skin phototypes
51
What is the difference between phototoxicity and photosensitivity?
phototoxicity is damage caused by prolonged exposure to light
photosensitivity is abnormal reactions of the skin to sunlight which is characteristic of certain diseases e.g. photodermatosis and a side effect of different drugs
52
What facial component is worth checking in the investigation of cutaneous photosensitivity
retroauricular area
53
What are porphyria?
A group of rare disorders due to inborn errors of metabolism in which there are deficiencies in the enzymes involved in the biosynthesis of haem. the accumulation of the enzymes substrate gives rise to the symptoms of the disorder
54
Cutaneous porphyria involves porphyrins as ___________ which are the chemicals that absorb radiation. Manifestations in the skin relate to where the porphyrins accumulate.
chromophores
55
What is the most common form of porphyria?
porphyria cutanea tarda
56
What enzyme has reduced activity in porphyria cutanea tarda? What porphyrin builds up as a result?
Uroporphyrinogen decarboxylase
| uroporphyrinogen
57
Name the symptoms of PCT
unilocular blisters
subcutaneous calcium deposits
skin fragility
hyperpigmentation
hirsutism- excessive hair growth for age/sex/race
solar urticaria
morphoea- skin thicker and firmer than normal (localised scleroderma)
58
How would you investigate PCT?
wood lamp of urine- appears pink in high levels of porphyrin
59
Having diagnosed PCT what is the next step?
```
Diagnose underlying condition causes=
alcohol excess
viral hepatitis
haemochromatosis
oestrogen
```
60
What enzyme has reduced action in erythropoietic porphyria? As a result, what substrate increases and what substrate decreases?
Ferrochelatase
protoporphyrin
Haem
61
In CEP what is the most common first sign?
Child has red urine
marked photosensitivity
anaemia
62
What do you call the middle and outer layer of the a hair?
middle-medulla
| outside-cuticle or cortex
63
What is the typical histological pattern of acute dermatitis?
spongiosis- fluid accumulation within vesicles
64
Give three histological features of psoriasis
parakeratosis- granular layer cells retain nuclei
micro-abscesses- neutrophil accumulation
elongated rete pegs- they are thicker and longer than usual
65
What is Toxic Epidermal Necrolysis (TEN)?
Drug induced keratinocyte death where epidermis detaches from the dermo-epidermal junction in large necrotic sheets.
66
Why does skin failure have a high mortality rate?
there is a loss of thermoregulation- contribute to CV risk
increased risk of infection
failure of homeostatic function- high fluid and electrolyte loss- CV risk
67
What are the three stages of wound healing?
first inflammation
second tissue remodelling and proliferation
third tissue remodelling
68
What is the difference between first, second and third degree burns?
1st- epidermis only- wet, erythematous and blistering
2nd (partial thickness)- epidermis and dermis
3rd (full thickness)- beyond dermis- white/black charred and numb
69
What are the characteristics of chronic skin wounds e.g. leg ulcers?
slough- mixture of dead cells, polymorphs and bacteria
often yellow/green colour
slow resolution
70
Give four causes of pressure sores
prolonged pressure over bony area
lack of blood flow
friction of bedding/clothing
irritation from sweat/blood/urine/faeces
71
How might you avoid pressure sores?
Use special mattresses, turn patient regularly, keep skin clean and hydrated, ensure regular skin assessment, ensure good nutrition
72
How do you differentiate between Staph Aureus and Staph epidermidis?
S. Aureus- coagulase positive
| S. epidermidis- coagulase negative
73
Give six possible presentations of S. aureus skin disease
impetigo, rash, carbuncle, folliculitis, abscess, scalded skin syndrome
74
What are toxinoses?
Diseases associated with a single protein component- a toxin or endotoxin
75
What does TSST-1 stand for?
Toxic shock syndrome Toxin-1
| causes a massive cytokine storm- inappropriate immune response
76
What are the diagnostic criteria for toxic shock syndrome?
Fever
diffuse macular rash and desquamation
hypotension
3+ organs involved
77
Give three examples of virulence factors of bacteria that allow them to evade host defences
Protein A
super antigens like TSST-1
Coagulase
Capsule
78
What condition is Streptococcus Pyrogenes primarily associated with? What family of strep. does it belong to? what distinguishes this family from others? what Lancefield group does it belong to?
Pharyngitis, scarlet fever
group A streptococci
Beta Haemolytic
A
79
Name three skin diseases associated with Strep. pyrogenes
impetigo
cellulitis
necrotising fasciitis
80
What is impetigo?
A strep pyrogenes/staph aureus skin infection that is associated with children, highly contagious and usually presents on the face
81
What is PVL?
Panton-Valentine Leukocidin
| attribute of staph aureus
82
Name two toxins associated with invasive GAS
streptolysin S
| haemolysin
83
Identify the three routes of drug administration using the skin
topical- diffuses into the skin to effect local area
transdermal- diffuses through the skin to the dermal capliiaries and then to other tissues and organs
subcutaneous- drug injected into the subcutaneous fat between the skin and muscle
84
What is the name of the protein crosslinks between the corneocytes that provide tensile strength to the layers
corneodesmosomes
85
What makes up the lamellar structures between the corneocytes? It acts as a reservoir for what type of drug?
intercellular lipids- ceramides, cholesterol, free fatty acids
Acts as a reservoir for lipid soluble drugs such as glucocorticoids
86
Name the three pathways by which topical drugs may passively diffuse across the stratum corneum
intercellular pathway
transcellular pathway
appendageal pathway
87
Identify the six vehicles of topical drugs
```
lotions
ointments
gels
creams
pastes
powders
```
88
What is the equation for Fick's law?
J=KpCv
Kp=permeability coefficient
Cv= concentration of drug in the vehicle
drug concentration and partition coefficient are dependant on the vehicle
89
In the case of a ___________ drug in a ___________ base the drug shall diffuse readily into the stratum corneum.
lipophilic
| hydrophilic
90
Give two ways of improving drug absorption by the skin.
hydration of the skin- vehicle used/cling film
| Excipient use- increase the solubility of hydrophobic drugs
91
Identify some of the effects of glucocorticosteroids like clobetasone
Possess anti-inflammatory, immunosuppressant, and vasoconstricting effects plus anti-proliferating action upon keratinocytes and fibroblasts
92
Name the three types of hair
Lanugo
Terminal
Vellus
93
What are the four diagnostic criteria of toxic shock syndrome
Fever
Hypotension
3+ organ involvement
diffuse macular rash and desquamation
