PHYSIOLOGY - skin structure Flashcards
which embryological layer does the epidermis come from
ectoderm
which embryological layer does the dermis come from
mesoderm
where does the neural crest come from embryologically
melanoblasts
what is the gastrulation stage of embryology
organisation into germ layers
how long does full regeneration of the skin (epidermis) take
28 days
what are blaschkos lines
the lines in which skin develops in
what is the outer most layer of the epidermis
keratin layer
what layer of the epidermis is internal to the keratin layer
granular layer
what layer of the epidermis is internal to the granular layer
prickle cell layer
what layer is internal to the prickle cell layer
basal layer
which layer is internal to the basal layer
dermis
what is the keratin layer also known as
stratum corneum
what 4 cells are in the keratin layer
keratinocytes
corneocytes
fillagrin protein
keratin protein
what are corneocytes
dead keratinocytes
where do keratinocytes originate
basal layer
what is the function of keratinocytes
vitamin D synthesis
when are keratinocytes activated
sunlight
what 3 cells are in the granular layer
lipids
odland bodies
birbeck granules
what does the prickle cell layer consist of
desmosomes (connections)
what 2 types of cells are in the prickle cell layer
birbeck granules
Langerhans cells
what do birbeck granules look like on histology
tennis rackets
what type of cells are Langerhans cells
dendritic cells
what does the prickle cell layer look like on histology (in comparison to the other layers)
‘prickly’ goes up and down in waves bc of the polyhedral cells
where is the basal layer
at the bottom
Basal = ‘Bottom’
what 2 cells are found in the basal layer
melanocytes
merkel cells
what do melanocytes do
convert tyrosine to melanin pigment
what are merkel cells
receptors - have nerves attached to them
which 2 layers is the dermal-epidermal junction between
basal layer of epidermis and the dermis
which layer contains muscles, blood vessels, lymphatics and nerves
the dermis
what is one of the main cells in the dermis
what is its function
fibroblasts
produces collagen
what type of corpuscle is in the dermis
meissener corpuscle
what type of corpuscle is in the subcutaneous fat
pacinian corpuscle
what are the 3 hair follicle growth phases
Anagen
Catagen
Telogen
(get in the ACT)
which hair follicle growth phase is the growing phase
anagen
in which hair follicle phase does the hair involute (curve)
catagen
what happens in the telogen phase of hair follicle growth
resting, nothing
hair can fall out
what type of cells are nail cells
specialised keratin cells
what is the growth rate of nails
0.1mm per day
what do sebaceous glands produce
sebum
where do you find sebaceous glands
mainly face and chest (but everywhere)
around hair follicles
which group of people to sebaceous glands not work in
pre pubertal
purpose of sebaceous glands
protect from fungal infection
control moisture loss
what do apocrine glands produce
sweat
where do you find apocrine glands (2)
axilla
perineum
which skin glands produce a smell
apocrine glands
where are eccrine glands (3)
everywhere esp;
soles of feet
palms of hands
how do eccrine glands release their produce
exits skin directly
Eccrine glands = Exit skin directly = are Everywhere
how do apocrine glands release their produce
via hair follicles
what is hyperkeratosis
increased thickness of keratin layer
what is parakeratosis
persistence of nuclei in the keratin layer
should there normally be nuclei in the keratin layer
if there is, what has happened
example
no
cell turnover has been too quick
psoriasis
how does psoriasis present on histology
parakeratosis - nuclei in keratin layer
what is acanthosis
increased thickness of epithelium
what is another word for acanthosis
hyperplasia
what is papillomatosis
irregular epithelial thickening
think papilloma = benign tumour = irregular in shape
what is spongiosis
oedema/fluid between cells
which cells does the skin have that are important for immune defence (2)
Langerhans cells
T cells
general function of keratin layer
waterproof barrier
what is the function of blood vessels in the skin
temperature regulation by vasoconstriction/vasodilatation
the production of melanin form melanocytes is significant because…
protects DNA from UV
