1. Integument Flashcards
(29 cards)
Characteristics of 5 layers of Epidermis
- corneum - keratinized 2. lucidum - only in thick skin, subdivision of stratum corneum, clear, homogenous layer 3. granulosum - intense staining granule 4. spinosum - spinous cell layer 5. basale - mitotically active cells
Thick vs Thin
thick vs thin corneum hand/feet vs everywhere All layers vs no lucidum and reduced granular layer
Heaviest amount of melanin
in Stratum basale (to shield nuclei from UV)
Stratum spinosum
Stratum granulosum
Thin
Pooly stained
Nuclei become pyknotic
Only seen in Thick
Looks identical wth stratum corneum in EM
Stratum Corneum
keratinized, flattened denucleated cells
Gives wear/tear function to skin
renewed
3 types of non-kerantinocytes in Epidermis
Melanocyte - resist staining, round cell bodies with long dendritic ending near basale/spinosum, Tyrosinase produced in ribosome -> rough ER -> Golgi -> melanosome -> melanin
langerhan’s cell
Merkel cell
function of Merkel cell
sensory receptors
responde to temperatre
characteristics of Merkel cell
cytoplasm has dense core granules
clear cells, desmosome connect to keratinocytes
present in basal layer
Merkel cell-neunite complex
unmyelinated sensory fiber associated with Merkel cell
2 layers of dermis
Papillary
Reticular layer
papillary layer of Dermis
immediately under epidermis
highyl vascular, less dense irregular fibroelastic CT
forms dermal papillae (interdigitate with epidermal pegs)
may contain capillaries or sensory endings
Reticular layer of Dermis
thick bundle
dense irregular CT
Both rich in collagen, elastic fiber
Dermis vs Epidermis
Epidermis - avascular
Dermis - vascular (capillaries in papillary layer)
Papillary layer of Dermis
Epithelial cell
derive hair, sweat gland, sebacceous, finger nails, mammary glands
Hair folicle
invagination of epidermis into dermis/hypodermis
ends as hair bulb
3 layers of mid-level follicles
outer root sheath
inner root sheath - dissolves and disappears at sebaceous gland level.
hair shaft
hair follicle characteristics
lined with stratified epithelium that is continuous with epidermis
In active follicles, matrix cells of bulb form cap over dermal papilla ( heavily oignmented stem cells that generate the hair)
Layers of hair follicle
Cortex -> cuticle -> internal root sheath -> external root sheath -> Glassy membrane -> Dermal sheath
sebaceous gland
outgrowth of outer root sheath
several acini end in duct
drains into upper hair follicle
holosecretion (Sebum)
stratified cells in alveloli (full of unstained cells)
hair buldge
mass of cells attached to hair follicle just below sebaceesous gland. (stem cells mirgrate to give rise)
bald still has hair follicles including hair buldge
Arrector pili muscle
smooth muscle bundle from CT of hair follicle below sebaceous gland to papillary for dermis
Contraction = goos bump
