Integument Flashcards
(23 cards)
name 5 functions of the skin
protection. body temp. vitamin d. excretion. sensory.
what does keratinocyte refer to. why?
epidermal cells because the IF is keratin and it will eventually kill the cell.
what are the differences between thin and thick skin
thin- low trauma areas. hair. only 4 layers. thick- high trauma areas. no hair. 5 layers. very thick stratum corneum
what is the deepest layer of epidermis?
basal layer (stratum basale)- one layer thick. mitotically active stem cells that produce all cells above it. cuboidal or low columnar. then contain a cap of melanin that protects them from UV damage.
what is the second deepest layer of the epidermis?
spinous layer (stratum spinosum)- several layers thick (thickest) of cells held together by desmosomes. tonofibrils are groups of keratin that are anchored to the attachement plaques of desmosomes
what is the third deepest layers of the epidermis?
granular layer (stratum granulosum) 3-5 layers of granular cells. granules contain keratohyalin which compacts the tonofibrils together. they also contain lamellar bodies that release a waterproofing seal
what is the least deep layer of the epidermis?
stratum corneum- many layers of dead, keratinized cells. deep cells still held together by desmosomes but superficial cells are not
ketosis pilaris
when keratin builds up in hair follicles
melanocytes
found in the basal layer, they secrete melanin. their cytoplasm is clear and they have tiny processes that extend out to give their melanin
langerhans cells
exist in all layers. they capture and present antigens to t cells. responsible for allergic dermatitis.
merkel cells
also found in the basement layer, they are touch receptors for fine touch and texture. usually associated with a nerve.
what are the two layers of the dermis
papillary and reticular. papillary is superficial with more loose CT that interdigitates with epidermis (dermal papillae or dermal ridges). contains blood vessels, mast cells, fibroblasts, nerves and macrophages. the reticular layer is dense irregular CT with more fibers and less cells. it is thicker than the papillary layer. blood vesses, nerves and glands are also present.
what creates finger prints?
dermal ridges
what is the point of the dermal ridges/dermal papillae?
to strengthen the dermal/epidermal junction
what is the hypodermis?
fat cells and CT deep to the dermis
describe the anatomy of a hair follicle
surrounded by a tube of epithelium. bottom of the follicle is the hair bulb, which contains dermal papillae. the dermal papillae has the blood supply for the hair. the cells around the papillae are the hair matrix, and they create the hair. melanocytes are also in the matrix and responsible for hair color.
sebaceous gland
a gland that secretes sebum via holocrine secretion, often found associated with hair and arrector pili muscles. simple branched acinar structure.
sweat glands
simple coiled tubular. myoepthelial cells assist with secretion. merocrine. 2 types- eccrine and apocrine
eccrine sweat glands
secretory portion- simple cuboidal with myoepthelium. duct portion- stratified cuboidal (2 layers). primary function is evaporative cooling. dark cells- granules. clear cells- electrolytes
apocrine sweat glands
found in axillary and anogenital region. large lumens. “socially offensive.” contain pheromones.
mammilary glands
compound tubuloalveolar. alveoli are simple cuboidal or columnar. modified sweat glands. become more active during pregnancy and after birth. secretion is both merocrine and apocrine. secreted into lactiferous ducts which drain into lactiferous sinuses
messiners corpuscle
pinecone. fine touch and texture. dermal ridge
pacinian corpuscle
deep in dermis. pressure and vibrations. onion.
