Ch. 5 Flashcards
what are the two later of the skin
epidermis and dermis
what is hypodermis composed of
areolar an adipose tissue
what are the 5 important functions of the skin
protection, body temperature regulation, excretion, production of vitamin D, sensory reception
what are the 4 main cell types found in the epidermis
keratinocytes, melanocytes, tactile epithelial cells, dendritic cells
keratinocytes
located in stratum spinosum produce keratin, fibrous protein
melanocytes
found in basal layer; manufacture and secrete pigment
tactile epithelial cells
found in basal layer; attached to sensory nerve endings
dendritic cells
found in stratum spinosum; part of immune system; macrophage-like
what are the layers of the epidermis
stratum basale, stratum spinosum, stratum granulosum, stratum lucid (only in thick skin), stratum corneum
what happens in the stratum basale
cells actively divide
what does the stratum basal contain
tactile epithelial cells and melanocytes
what does the stratum spinosum contain
thick bundles of intermediate filaments, dendritic cells
what does stratum granulosum consist of
few layers of keratinocytes
what do keratinocytes contain
keratohyaline granules- help form keratin, lamellar granules-contain waterproofing glycolipid
descrie stratum lucidum
occurs only in thick skin (palms and soles), composed of a few rows of flat, dead keratinocytes
describe the stratum corneum
thick layers of dead keratinocytes and thickened plasma membranes, protects skin against abrasion and penetration
what are the two layers of the dermis
papillary dermis (includes dermal papillae) and reticular dermis (deeper layer)
describe the papillary dermis
includes dermal papillae, increase surface area for exchange of gases, nutrients, and wastes
what are epidermal ridges (friction ridges)
elevation of dermal ridges, AKA fingerprints
purpose of epidermal ridges
increases gripping ability of hands and feet
cleavage lines
separation b/t collagen fibers
flexure lines
deep creases in palms, wrists, soles, finger, and toes
what are the two types of vascular plexuses found in the reticular dermis
dermal plexus, and sub papillary plexus
what type of tissue is in the hypodermis
areolar and adipose connective tissue
function of hypodermis
anchors skin to underlying structures, helps insulate body
what is another name for the hypodermis
superficial fascia
name the 3 pigments that contribute to skin color
melanin, carotene, hemoglobin
what is melanin made of
made from tyrosine
carotene
yellowish pigment from carrots and tomatoes
hemoglobin
caucasian skin contains little melanin, allows crimson color of blood to show though
nails
scalelike modifications of epidermis make of hard keratin
list the parts of the nail
free edge, body, root, nail folds, eponychium
describe hair
flexible strand of dead, keratinized cells
what are the parts of hair
root (embedded in skin), and shaft (projections above skin’s surface)
name the 3 concentric layers of keratinized cells hair contains
medulla (center core), cortex (surrounds medulla), and cuticle (outermost layer)
hair follicles
extend from epidermis into dermis
hair bulb
deep, expanded end of he hair follicle
root plexus
knot of sensory nerves around hair bulb
arrestor pili muscle
bundle of smooth muscle, hair stands erect when arrector pili contracts
villus hairs
body hairs of women and children
terminal hairs
hair of scalp, axillary, and pubic area (at puberty)
sebaceous glands are found one entire body except
palms and soles
function of sebum
collects dirt; softens and lubricates hair and skin
what is sweat
a blood filtrate, 99% water w/ some salts
what are the two types o sweat glands
eccrine gland (merocrine) and apocrine gland
what do eccrine gland (merocrine) produce
produce true sweat
where are apocrine glands confined
axillary, anal, and genital areas
what do procaine glands produce
special kind of sweat, musky odor attracts mate; signal info. about person’s immune system etc.
name 2 modified apocrine lgands
ceruminous glands and mammary glands
describe first degree burns
only upper epidermis is damaged
describe second degree burns
upper part of dermis is also damaged; blisters appear, skin heals w/ little scarring
describe third degree burns
consumes thickens of skin, area appears white, red, or blackened
what are the 3 types of skin cancer
basal cell carcinoma, squamous cell carcinoma, and melanoma
what type of skin cancer is the least malignant and most common
basal cell carcinoma
what is the most dangerous type of skin cancer
melanoma
where does the epidermis develop from
embryonic ectoderm
where does the dermis and hypodermis develop from
mesoderm
what do melanocytes develop from
neural crest cells
