Term | Description |
Keratinocytes | majority puoduce keratin (fibrous protien), joined by desmosomes, stratum basale, live 25-45 days |
Melanocytes | make melanin, stratum basale, melanin granules eventually sent to keratinocytes |
Merkel cells | occasional, associated w/ sensory nerve endings for touch |
Langerhans' cells | macrophages, stratum spinosum |
Stratum corneum | cornified layer, composed of flattened thick keratinized cells that protect against abrasion/penetration but constantly exfoliate, dead cells |
Stratum spinosum | Spiny layer, containing many keratin fibers and desmosomes, resists tension |
Stratum basale | constant mitosis replaces epidermis from basal layer |
Stratum granulosum | keratin forming granules, lamellated granules, cells beginning to flatten and membrane thickens |
What is thick skin? | skin of palms, soles, and fingertips. Has an extra layer under corneum: stratum lucidum |
What are the layers of the epidermis (superficial to deep, thin skin) | stratum corneum, stratum granulosum, stratum spinosum, stratum basale |
Apoptosis | normally cells of trans/intermed. layers of epidermis go through this, resulting in protective layer of flattened dead cells of cornified layer |
Squamous cell carcinoma | cancer occuring in keratinocytes of intermediate or transitional layers of the epidermis |
Basal cell carcinoma | abnormal growth of basal cells |
Melanoma | cancer of melanocytes and is most dangerous bc often metastizes to other tissues/organs |
Dermis type of tissue | dense connective tissue |
Dermis common cells | fibroblasts, macrophages, some mast cells and WBC |
Dermis semi fluid matrix | collagen, elastin, reticular fibers |
Dermis layers | 2 layers: Papillary (areolar connective tissue) and Reticular layer (dense, irregular conn tissue) |
Papillary layer | thin, dermal papillae(upper edges) , dermal ridges (form fingerprints) |
Reticular layer | cleavage lines (affect incision gapes), flexure lines (folds around joints) |
Eccrine glands | most common, important for thermoregulation, acidic, sweat mostly water |
Apocrine glands | dont secrete anything till puberty, sweat, fat , and protiens, pheromones |
Ceruminous glands | modified apocrine gland, earwax |
Mammary gland | specialized sweat gland, secretes milk |
Sebaceous glands | secretes sebum, softens and lubricates hair and skin, simple holocrine gland |
Things involved in touch feeling in skin | merkel cells, root hair plexus, meissners corpuscle, pacinian corpuscles, free nerve endings |
arrector pili function | raises skin in goosbumps to produce insulating layer of air |
Hair follicle layers from middle to outside | medulla, cortex, sheath. hair papilla protrudes up into hair root, then matrix (for growth) on top of that |
Nails | composed of hard keratin, growth similar to hair |