skin histology module Flashcards
thick skin does not have
hair follicles, sebaceous glands, arrector pili muscles
where is thick skin
what does it lack
palms and plantar
lacks hair follicles, sebaceous glands
what is thin skin
what does it lack
lacks a stratum lucidum
most superficial layer of skin
epidermis
shape of cells in epidermis
stratified squamous keratinized epithelium
also melanocytes, langerhans and merkel cells
regeneration of epidermis
constant - about every 30 days
carried out by mitotic keratinocytes
cells normally divide at night
desmosomes
connect kerotinocytes together
hemidesmosomes
connect keratinocyte to basement membrane
where are melanocytes?
stratum basale
function of melanocytes
synthesize melanin in melanosomes
what does melanin do
protect against tissue damage and degradation patters
_____ increases production and changes of melanocytes
sunlight
where are langerhans cells located
primarily in the stratum spinosum
shape of langerhans cells
comma like appearance, appears pale
function of langerhans cells
antigen presenting cells in immune responses to contact antigens/allergies and some skin grafts
birbeck granules
inside langerhans cells - cytoplasmic organelles that look like tennis racket
where are merkel cells
stratum basale enar areas of well vascularized, richly innervated connective tissue
function of merkel cells
receive afferent nerve terminals and are believed to function as sensory mechanoreceptors
stratum basale
deepest layer of the epidermis
composition of stratum basale
keratinocytes, melanoyctes, langerhans, merkel
stratum spinosum
- keratinocytes connected by desmosomes
- mitotically active in deeper region
keratinocytes membrane coating granules
in the superficial regions of the stratum spinosum, the contents of the granules are released into the intercellular spaces in the form of lipid-containing sheets that are impermeable to water and many foreign substances
stratum granulosum
most superficial layer in which nuclei are still present
3-5 (10-12 nm thick) layers of flattened keratonocytes with keratohyalin granules