Non-keratinocyte epidermal cells, and appendages Flashcards
what are the non-keratinocyte epidermal layer cells
melanocytes(basal + suprabasal), Langerhans cells(suprabasal), Merkel cells(basal)
briefly describe what melanocytes are
pigment producing dendritic cells
describe the role of melanocytes
convert tyrosine to melanin pigment, melanin absorbs light, forms protective cap over nucleus
describe where the organelles in melanocytes, full melanosomes(‘melanin granules’) are transferred to and via what
transferred to adjacent keratinocytes, via dendrites
where are Langerhans cells found
prickle cell layer of epidermis, dermis and lymph nodes
describe Langerhans cells involvement in the immune system
antigen presenting cells, pick up antigen in skin and circulate to lymph nodes via lymphatic system
what is the origin of Langerhans cells
mesenchymal origin - bone marrow
describe where Merkel cells found
in the basal epidermis between keratinocytes and nerve fibres
what is the function of Merkel cells
mechanoreceptors
what is another name for a hair follicle
Pilosebaceous unit
describe what hair pigmentation is due to
via melanocytes above the dermal papilla
what is the pilosebaceous unit made up of
the epidermal component plus the dermal papilla
what are the different growth cycles of hair
anagen(growing), catagen(involuting), telogen(resting/shedding phase)
describe how long each of the hair growth phases takes
anagen = 3-7 years(90% of hairs) catagen = 3-4 weeks(10% hairs) telogen = each day 50-100 hairs(<1%)
what word is used to describe the pattern of telogen phase of hair growth in humans
asynchronous
