Chapter 5 Flashcards
superficial fascia
superficial to the tough connective tissue wrapping the skeletal muscle (called fascia)
Epidermis layers from superficial to deep
stratum corneum, stratum lucid, stratum granulosum, stratum spinosum, stratum basale
Epidermis layers from deep to superficial
stratum basale, stratum spinosum, stratum granulosum, stratum lucid, stratum corneum
Keratinocytes
produce keratin
Four distinct cell types
keratinocytes, melanocytes, dendritic cells, tactile cells
Dendritic cells
star-shaped macrophages = phagocytic
AKA: Langerhans cells
Tactile cells function
sensory receptor for touch
Stratum corneum
AKA: horny layer
Stratum lucidum
clear layer
Tonofilaments
are keratin intermediate filaments that makes up tonofibrils in the epithelial tissue
Stratum granulosum
granular layer
Stratum spinosum
prickly layer
Stratum basale
basal layer or stratum germinativum
Dermal papillae
peg-like projections indenting the overlying epidermis
Cleavage (tension) lines
separations or less dense regions between bundles, tend to run
Langer’s lines
important in surgery (want incisions parallel)
Flexure lines
dermal folds that occur at or near joints where dermis is tightly secured to deeper structures
Melanin in albinos
missing
Shaft
portion in which keratinization is complete and projects from the skin and extends about halfway down portion of hair embedded in skin
Root
area where keratinization is still ongoing
Medulla
central core consisting of large cells and air spaces, only part of hair that contains soft keratin
Cortex
bulky layer around medulla, consists of several layers of flattened cells
Cuticle
single layer of cells overlapping each other like shingles on a roof, provides strength and keeps inner layers tightly compacted
Papilla of hair follicle
nipple-like bit of dermal tissue protruding into build and supplies nutrients and signals hair to grow
Wall of hair follicle
outer peripheral connective tissue sheath derived from dermis, thickened basal lamina, inner epithelial root sheath
Hair matrix
actively dividing area of hair bulb
Hair bulge
located a fraction of a mm above the hair bulb
Arrector pili
bundle of smooth muscle cells that pulls hair follicle upright and dimples the skin in response to cold temperatures or fright
Nails contain
hard keratin
Free edge
nail tip
Nail plate or body
visible attache portion
Proximal root
embedded in skin
Nail bed
extension of deeper layers of epidermis
Nail matrix
responsible for nail growth
Sweat
hypotonic filtrate from blood released by exocytosis to prevent overheating
Dermicidin
microbe-killing peptide
pH of sweat
between 4 to 6
Sebaceous (oil) glands
hormonally activated (esp. as teenagers)
Function of sebum
softens and lubricates skin and hair, prevents moisture loss, bacterial action
Dendritic cells of the epidermis
active elements of the immune system and play the role of antigens
Macrophages in dermis
second line of defense and dispose of viruses and bacteria that penetrate the epidermis
DNA
absorbs UV radiation and transfers it to atomic nuclei
insensible perspiration
don’t notice this routine sweating
