Integument Flashcards
integument includes what layers?
epidermis, dermis, hypodermis, hair, nails, glands, & nerves
what are the functions of the integument?
protection, thermoregulation, sensory, metabolic, secretion
where is thick skin located?
palms of hands and soles of feet (no hair follicles)
where is thin skin located?
skin other than palms and soles of feet; thinner epidermis than thick skin & has hair follicles
stratified squamous epithelial cells produce what?
keratinocytes
what are the epidermal layers?
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
characteristics of stratum basale?
single layer of columnar to cuboidal shaped cells; numerous mitotic figures; numerous intermediate filaments (tonofilaments); desmosomes
what binds cells to basal lamina?
hemidesmosomes
characteristics of stratum spinosum?
cells: cuboidal, polygonal, slightly flat; cytokeratin aggregates to form tonofibrils; some mitotic figures
characteristics of stratum granulosum?
3-5 layers of flat polygonal cells; basophilic cytoplasm with keratohyaline granules; rod-like lamellar granules (keratinosomes); has glycolipid penetration barrier
characteristics of stratum lucidum?
only in thick skin; thin layer of eosinophilic, newly keratinized cells; no organelles/nuclei; contains eleidin (product of keratohyalin)
characteristics of stratum corneum?
15-20 layers of flat nonnucleated cells with keratin
dead flattened cells
squames
what is necessary for skin healing?
retinol (vitamin A) because its a factor for keratinocyte differentiation
first degree burn?
extends down to stratum lucidum
second degree burn?
extends down to stratum basale
third degree burn?
extends into dermis
where are glycolipids secreted to form multilayered lipids intracellularly?
stratum granulusom
what links to the side of the cell membrane of stratum corneum?
protein complex of involucrin-small proline rich loricrin complex & keratin-filagrin aggregates
melanocytes
pigment producing cells of stratum basale derived from neural crest
cytocrine secretion
process by which melanocytes distribute melanin to other cells & hair
what cells undergo exocytosis & endocytosis of pigment granules?
keratinocytes
where does melanin form?
melanosomes derived from golgi
which enzyme is needed for melanin synthesis?
tyrosinase
addison’s disease
lack of cortisol from adrenal cortex which causes overproduction of ACTH —-> increases skin pigmentation
albinism
melanocytes do not make melanin
loss of melanocytes causes?
depigmentation (vitiligo)
langerhan’s cells
star shaped; mostly in stratum spinosum/dermis near blood vessels
where are langerhan’s cells derived?
bone marrow (magrophage lineage)
what is something langerhan’s cells don’t do?
form desmosomal attachments with other cells
describe the granules in a langerhan’s cell
membrane bound, rod like shape called birbeck or vermiform granules that contain proteins (langerin) for antigen uptake
merkel’s cell
tactile epitheloid cell associated with sensory nerve ending; primarily in thick skin of palms/soles; base of cell in contact with neuron
what does the cytoplasm of a merkel’s cell contain?
small dense granules that may be related to catecholamine granules of neurosecretory cells
dermis
made of CT; supports epidermis & binds it to hypodermis (subcutaneous tissue)
how does the dermis connect with the epidermis?
dermal papillae
epidermal counterpart to dermal papillae?
epidermal ridges or rete ridges
anchoring fibrils
collagenous; extend from basal lamina to dermis/epidermis by anchoring plaques
papillary layer of dermis made of?
loose CT (fibroblasts, mast cells, & macrophages)
reticular layer of dermis composed of?
dense irregular CT; thicker than papillary layer
dermis also contains
follicles, sweat & sebaceous glands, nerves
which layer is important for thermoregulation?
papillary layer —> extensive capillary network
hypdermis
deeper continuation of dermis made of loose CT & adipose tissue
where are pacinian corpuscles found?
dermis/hypodermis junction
hair follicle
invagination of epidermis that terminates in a hair bulb
dermal papilla projects into?
hair bulb
what forms the hair root?
epidermal cells covering dermal papilla that continues with hair shaft
what forms hair medulla?
cells at apex of dermal papilla produce large, vacuolated, keratinized cells
what forms hair cortex?
cells in papilla differentiate into fusiform, heavily keratinized cells
what produces hair cuticle?
peripheral cells in root
internal and external root sheath produced by?
peripheral root cells
glassy membrane
separates hair follicle from dermis; thickened basal lamina
arrector pili muscles
smooth muscle bundles extending from dermis papillary layer to hair follicle CT sheath
sebaceous glands
not on palms/soles; holocrine gland
sebum
dead cells & cell contents
sweat glands (sudoriferous glands)
eccrine/merocrine sweat glands (simple coiled tubular glands) that receive cholinergic nerve fibers
where do merocrine glands open into?
skin surface
where is the secretory portion of sweat gland?
deep in dermis
what kind of cells do sweat glands have?
myoepithelial cells (contractile); dark cells=mucoid/pyramidal cells; clear cells=no secretory granules but lots of glycogen
what do dark cells secrete?
glycoproteins (mucous)
what do clear cells secrete?
water & electrolytes into intercellular canaliculi
apocrine glands located?
axillary, areolar, & anal regions —> ducts open into hair follicles
what do apocrine glands produce?
viscous protein containing secretion
what nerve fibers do apogrine glands receive?
adrenergic
what mechanism of secretion does apocrine glands have?
merocrine mechanism
liver spots
large freckle due to sun exposure in older people
actinic keratosis
precancerous condition of thick scaly patches of skin
basal cell carcinoma
90% of skin cancer; slow growing & treatable
squamous cell carcinoma
develops in sun damaged areas (actinic keratosis due to sun damage)
malignant melanoma
derived from melanocytes; difficult to treat
psoriasis
immune related, genetic disease; red scaly patches of skin due to inflammation and hyperplasia —-> joint problems
