derm 2 Flashcards
Function of the hair (6)
Protection against external factors Sebum- oily substance on our skin Apocrine sweat Thermoregulation Social and sexual interaction reservior for Epithelial and melanocyte stem cells
what is Terminal hairs
scalp, eyebrows and eyelashes, beard
what sort of hair covers the rest of our body
vellus hairs
what regions have no hair
(except palms, soles, mucosal regions of lips, and external genitalia.
what are the stages to hair cycle (3)
Anagen
Catagen
Telogen
(then loss of hair)
what is anagen
where new hair forms and grows
catagen
regressing phase(hair is shrinking) lasts 3 weeks
telogen
resting phase (blood supply removed from hair) lasts 3 months
what is a hair follicle
pilosebaceous follicles
where does the sebaceous gland open
at the hair follicle
what sort of muscle is the Arrector pili
smooth muscle
what orientation is it
extends at angle between surface of dermis and point in follicle wall.
Holocrine sebaceous glands which open into the ….
pilary canal → in axillae - follicles associated with apocrine glands.
what is the Infundibulum
Uppermost portion of the hair follicle extending from opening of sebaceous gland to surface of the skin
what is the sebaceous gland (function)
secreates sebum
what is the isthmus
Lower portion of upper part of hair follicle between opening of sebaceous gland and insertion of arrector pili muscle
where is the buldge
Segment of the outer root sheath located at insertion of arrector pili muscle
what is special about the buldge
hair foliicle stem cells reside there
what happens if they migrate downwards
generate the new lower anagen hair follicle → enter hair bulb matrix, proliferate and undergo terminal differentiation to form hair shaft and inner root sheath.
and upwards
form sebaceous glands and to proliferate in response to wounding
function and location Outer root sheath (ORS)
Extends along from the hair bulb to the infundibulum and epidermis serves as a reservoir of stem cells
function of Inner root sheath
Guides / shapes hair
Encloses follicular dermal papilla, mucopolysaccharide-rich strome, nerve fiber & capillary loop.
Function of the nails (5)
Protection of underlying distal phalanx
Counterpressure effect to pulp important for walking and tactile sensation
Increase dexterity / manipulation of small objects
Enhance sensory discrimination
Facilitate scratching or grooming
how is the nail plate made
Final product of proliferation and differentiation of nail matrix keratinocytes- lose organelles and become keratin
what is the only visible part of the nail matrix
lunula
how does the nail matrix produce the nail plate
Nail matrix keratinocytes differentiate → lose their nuclei and are strictly adherent - cytoplasm completely filled by hard keratins
does it contain melanocytes in the matrix
yes
what does white or red show on skin
red- inflammation
white- keratin
what is Psoriasis
Chronic, immune-mediated disorder
can a genetic predispostion cause it
not enough on its own, need enviromental triggers
what are the cells involved
involves T-cells and their interactions with dendritic cells and cells involvement in innate immunity, including keratinocytes
what does it cause on the skin
(chronic plaque psoriasis) Sharply demarcated, scaly, erythematous plaques characterise the most common form of psoriasis
where is it commonly found
of involvement are scalp, elbows and knees, followed by nails, hands, feet and trunk (including intergluteal fold)
doe sit just invlove the skin
Psoriatic arthritis is most common systemic manifestation
what is the pathophysiology in psoriasis
Stressed keratinocytes release DNA / RNA → form complex with antimicrobial peptides → induce cytokines (TNF-α, IL-1 and IFN-α) production → activate dermal dendritic cells (dDCs)
what do the dermal dentrictic cells do
dDCs migrate to lymph nodes → promote Th1, Th17, Th22 cells → chemokine release – migration of inflammatory cells into dermis → cytokine release → keratinocyte proliferation → psoriatic plaque
what are the clinical features
plaques/scales,
can occur on the nails
what is erythroderma
inflammation that occurs to more than 90% of skin, lose the skin properties like more vunreable to infection
what can aggrivate psioris
smoking and drinking
how is it managed
Topical therapies
like vit d analogs or vit a analogs
phototherapy- causes t cell apoptosis
narrowing UVB
PUVA
what is atopic eczema
Intensely pruritic chronic inflammatory condition
what is pruritic
causes itching
is it enviro or gentic
both
when does it start
infancy or early childhood
what is the difference between eczema and dermatitis
nothing
how to treat
Daily emollients and anti-inflammatory therapy are cornerstone of management
what is the function of Filaggrin
bind and aggregate keratin bundles and intermediate filaments to form cellular scaffold in corneocytes
what is the diff in the filaggrin with people with eczema
muatated filaggrin
function of corneocytes
essential part of skin barrier. property
what is a resuolt of this
increase transepidermal water loss (TEWL)
what does that cause
Impaired protection against microbes and environmental allergens
what causes the inflammation
Staphylococcal superantigens stimulate Th2 lymphocyte responses and subvert T‐reg
SPCL find the skin of eczma more hospitable
are eosinophils inlvoled
yes
what signs/symo of eczema are there in skin
Acute inflammation of cheeks, scalp and extensors in infants
and adults/children
Flexural inflammation and lichenification in children and adults
thikening of skin due to extensive/chronic ithcing
disorded pigmentation
exgerrated of normal skin marking
what happens when you lose the hydration of the epidermis
less flexible
casuing fissuring
v painful affect quality of life
what is Allergic contact dermatitis
allergic caused by contact with substance
what is a feature of Atopic eczema
(Impetiginisation)
what pathogen causes it
Gold crust
Staphylococcus aureus
what is Venous stasis eczema
is a long-term skin condition that affects the lower legs
barrier function lost
what are erosions
breaches to epidermis that dont go all the way thru- if they did they would be ulcers
what is Eczema
herpeticum
emergency, not to be confused with eczema
breakdown of the skin barrie
more pron to herpes virus
how to treat atopic eczema
Lifestyle Emollients (at least 3 times a day) Omission of soap Clinical Nurse Specialist involvement Topical application technique Day treatment Habit reversal(stop them itching) Co-morbidities
how to tell that it is not due to allergy
Patch testing
Biopsy
when would you do biopsy
nipple eczema that dioesnt repsond to treatment
to exclude pagents disease
Adverse effects of topical corticosteroids:
Rare: skin atrophy, folliculitis, exacerbation of acne and rosacea, infection
Very rare: perioral dermatitis (right), rebound syndrome (tachyphylaxis), allergy (to steroid itself or vehicle)
Extremely rare: hormonal imbalance (suppression of hypothalamic-pituitary-adrenal axis), hirsuitism
Adverse effects of topical calcineurin inhibitors:
Burning sensation
what is the aporcrine gland
a modified suncaoues gland
how many layers do soles and palms have
5 (lucidium is only in the soles and palms)
the evapouration of sweat which cools you down
epinochyiom
in the exam
