cutaneous membrane/integument system Flashcards
(30 cards)
skin divided into 3 layers
epidermis (thin superficial), dermis and hypodermis (thick and deep)
dermis CT contains
elastin and collagen fibres
four types of cells in epidermis
keratinocytes, melanocytes, langerhans, tactile cells (Merkel cells)
keratinocytes produce
keratin (tough fibrous protein that fills the cell) and lipid rich granules
are keratin and lipid rich granules exocytosed out of cell
only lipids. keratin stay in cell
fn of keratinocytes
mitose make lots of keratin, exocytose lipid, die and protect
skin colour is influence by (2)
blood circulation rbc, 2 pigments (carotene and melanin)
carotene is
orange yellow pigment. accumulates in epidermal cells and fatty tissues of the dermis
melanin is
yellow-brown or black pigment
describe melanin movement
produced by melonocytes in stratum basale. stored in transport vesicles (melanosomes). transferred to keratinocytes
how do melanocytes form a sunshade
injected into keratinocytes. accumulates and locates itself to form sunshade for nuclei
fn of melonocytes
melanin protects from sun damage. UV radiation causes mutation + burns (cancer + wrinkles)
skin colour depends on
melanin production not number of melanocytes
langerhans cell aka
dendritic cells
langerhans cells are produced in
bone marrow and migrate to stratum spinosum of epidermis
fn of langerhans cells
fn in immune response against pathogens that enter epidermis
how does dendritic cells kill pathogens
engulf ones that enter epidermis (phagocytosis) and migrates to immune system
merkel cells located in
stratum basale
merkel cell fn
detect light touch sensation
what are tactile (merkel) disc
specialised sensroy nerve endings
lest numerous epidermal cells
merkel cells
most abundant epidermis cells
keratinocytes
in which layer does keratinocyte start to die
stratum granulosum
thick skin on palms is due to which epidermis layer
stratum lucidum
