Physiology Flashcards
layers of the skin
epidermis appendages dermo-epidermal junction dermis sub-cutis layer
what are the epidermal layers?
keratin layer
granular layer
prickle cell layer
basal layer
what is the epithelium of the epidermis?
stratified squamous epithelium
another name for the keratin layer?
stratum corneum
what is the keratin layer made up of?
corneocytes and lamellar granules with lipids and keratinocytes
what are corneocytes?
keratinocytes that have lost their nuclei
what is the granular layer made up of?
flatten cells with keratohyalin granules (Odland bodies) with filaggrin and involucrin proteins
prickle cell layer
polyhedral cells with desmosomes
basal layer
cells with high metabolic rates and melanocytes
role of melanocytes in the basal layer
absorb sunlight and converts tyrosine to melanin for pigmenting hair and skin
what migrates from the basement membrane to the stratum corneum over 28 days?
keratinocytes
what are keratinocytes involved in?
vitamin D production
conditions where epidermal turnover control is lost?
cancer
psoriasis
other cells in the epidermis
Langerhans cells (Birbeck granules) merkel cells
appendages in the skin
nails
hair
glands
what are hairs in the skin attached to?
arrector pili
sebacous gland
how are hairs pigmented?
melanocytes
phases of hair growth
anagen (growing)
catagen (transitioning)
telogen (resting)
three types of glands in the skin
- sebaceous
- apocrine
- eccrine
describe sebaceous glands
attached to hairs
hormone sensitive
produce sebum
describe apocrine glands
present in axilla and perineum
androgen dependent
describe eccrine glands
whole skin surface controlled by sympathetic nerves
ultrafiltration
thermoregulation
cells that make up the dermis
connective tissue fibroblasts macrophages mast cells fibres ground substances
role of fibroblasts in the dermis
produce collagen
