Skin Flashcards
4 cell types in epidermis
- keratinocytes
- merkel discs
- meloncytes
- langerhans/dendritic
does the epidermis have a blood supply?
no
function of epidermis
strength and barrier to water loss + infection
how are keratinocytes connected?
via desmosomes and hemidesmosomes
origin of keratinocytes
ectoderm
origin of melanocytes
neural crest
where in the epidermis are melanocytes located?- 2
basal layer and hair bulb
via which enzyme do melanocytes create melanin?
tyrosinase
function of melanine
protect cell nucleus from harmful UV light
what is albinism
melanocytes cannot produce melanin due to lack of tyrosinase
benign and malignant skin cancers
benign = lentigos malignant = nevi`
origin of langerhans
mesoderm
where in the epidermis are langerhans cells found
upper and middle spinous layer
function of dendritic/langerhans cells
phagocytotic
origin of merkel cells
ectoderm
where in the epidermis are merkel cells found
basal layer
function of merkel cells
light, touch and pressure receptors
how many layers of epidermis;
i) thick skin
ii) thin skin
i) 5
ii) 4
name for shedding of skin cells
desquamation
protein found in granular layer of epidermis
filaggrin
function of filaggrin
retains water in keratinocytes as barrier
which 2 diseases are caused by mutations in filaggrin?
asthma and atopic dermatitis
5 layers of skin top to bottom
Basale Spinosum Granulosum Lucidum Corneum
which layer of epidermis is only in thick skin
stratum lucidum
4 cells in S. basale
stem
keratinocytes
melanocytes
merkel
4 cells in S.Spinosum
keratinocytes
desmosomes
prickle
langerhans
in which epidermal layer do keratinocytes begin to die
S. granulosom
where is the cornified envelope?
epidermis - S. Granulusom
function of cornified envelope
separates layers of inner active cells and outer layers of dead keratinocytes
which epidermal layer do K exit mitosis?
S.Spinosum
what are corneocytes? where are they?
epidermal S. lucidom - dead keratinised cells
in what strata are keratin fibres produced and lamellar bodies formed?
S. spinosum
in what strata do lamellar bodies release lipids?
S. granulosum
is the dermis vascularised?
yes
in what skin layer are hair follicles, seb glands and sweat glands produced
Dermis
2 layers of dermis - state upper and lower
upper - papillary
lower - reticular
what protein is contained in dermal layers
collagen
fingerlike projections in papillary dermal layer
dermal papillae
what 3 things do dermal papilllae contain
- free nerve endings
- light touch receptors (m-corp)
- capillary loops
what pressure + stretch receptors are contained in reticular layer
pacinian corp + ruffini endings
3 types of cell i dermis
- fibroblasts
- mast cells
- dermal macrophages
what disease of the skin are mast cells the main effector?
urticaria
major tissue in hypodermis
adipose
function of hypodermis
shock absorber
which layer of skin thickens with weight gain?
hypodermis
muscle near hair shaft
arrector pilli muscle
what creates new hair cells
hair matrix
dermal tissue containing capillaries
hair papilla
3 stages in hair cycle
- anagen
- catagen
- telogen
growing hair phase
anagen
degenerative hair phase
catagen
resting hair phase
telogen
condition of excessive hair growth
hirsuitism
what causes hirsuitism
tumours of ovary and adrenal gland produce excess androgens
what is poly-cystic ovary syndrome
benign cyst in ovary affecting hormones
what is alopecia areata
immune system attacking hair follicles
3 types of skin glands
merocrine
apocrine
holocrine
type of skin gland - sebaceous glands
holocrine
type of skin gland - sweat glands
apocrine and merocrine
process of merocine glands
exocytosis
process apocrine glands
lipids leaving in cell membrane fragments
process of holocrine glands
rupture
sweat secretion composition of merocrine sweat glands
watery - 1% salt
sweat secretion composition of apocrine sweat glands
viscous and milky - fats and proteins
which 2 places are apocrine sweat glands located?
axillary and anogenital