BIO1110- CHP5- INT System

stratum corneum location

outermost layer

stratum lucidum location

between stratum corneum and stratum grandulosum

thick sick like hands and feet

where is stratum lucidum only present in

stratum granulosum location

beneath the stratum corneum

stratum spinosum location

beneath the stratum granulosum

stratum basale location

deepest layer

stratum corneum characteristics

layers of keratinized, dead epithelial cells that are flat and non-nucleated

stratum lucidum characteristics

cells appear clear; nuclei, organelles, and cell membranes are no longer visible

stratum granulosum characteristics

3-5 layers of flattened granular cells contain shrunken fibers of keratin and shriveled nuclei

stratum spinosum characteristics

Many layers of cells with centrally located, large, oval nuclei.

Developing fibers of keratin; cells become flat

stratum basale

single row of cuboidal or columnar cells that divide and grow; layer includes melanocytes

dendritic (langerhans) cells

Found in stratum spinosum

preforms phagocytes

protects skin and underlying tissue from infection

tactile (merkel) cells

found in stratum basale

act as sensory receptors for light touch

melanocytes

found in stratum basale

produces melanin

absorbs UV from sunlight

provides skin with color

eumelanin

brownish-black pigment of the epidermis

pheomelanin

reddish yellow pigment

papillary layer and reticular layer

the dermis can be divided into

papillary layer

superficial layer, areolar connective tissue, thinner than the reticular layer, location of dermal papillae

reticular layer

deeper layer compared to papillary layer, dense irregular connective tissue, thicker than papillary layer

hair follicle

tube-like depression of epidermal cells from which hair develops; extends into the dermis or subcutaneous layer

hair root

extends from skin surface to dermis or hypodermis

hair bulb

deepest part of hair root; contains dividing cells of hair matrix

hair shaft

portion of hair that extends beyond the skin surface; composed of dead, epidermal cells

hair papilla

contains blood vessels to nourish hair

arrector pili muscle

Attached to hair follicles, contracts in response to cold or fear, causes goosebumps, raises hair in response to cold

sweat (sudoriferous) glands

widespread in skin

originate deeper dermis or hypodermis as ball-shaped coils

apocrine sweat glands

axillary and groin areas; open into hair follicles

secrete by exocytosis

respond to emotions, pain

specialized sweat glands

ceruminous glands— ear wax

mammary glands— milk

found in the dermis

merocrine (eccrine) sweat glands

odorless, lowers body temperature, located in deep dermis, on your forehead and back

first degree burn

injures epidermis, no scarring, healing takes days to weeks

second degree burn

destroy epidermis and some dermis, may blister, stem cells and hair follicles and glands can help regenerate skin

third degree burn

destroys epidermis, dermis, and accessory structures, requires skin graft, prolonged exposure to heat

epidermis

composed of stratified squamous epithelium

basement membrane between epidermis and dermis

no blood vessels

hypodermis

insulating layer, contains blood vessels

sebaceous glands

associated with hair follicles, produce sebum, absent in palms and soles

sebum

fatty material and cellular debris

functions of the skin

protective barrier

sensation

excretion

production of vitamin D

regulates body temp