Ch 6 the Integumentary System Flashcards
what are the functions of the integumentary system
protection, body temperature regulation, cutaneous sensation, metabolic (synthesis of vit D) blood reservoir, excretions
epidermis
composed of keratinized stratified squamous epithelium, it contains keratinocytes, melanocytes, Merkel cells, and Langerhans’ cells
keratinocytes
produce keratin
Langerhans’/dendritic cells
epidermal microphage that helps activate immune system
melanocytes
produce brown pigment melanin (UV protection)
Merkel cells
touch receptors in association with sensory nerve endings
stratum basale
deepest epidermal layer, attached to dermis, single row of youngest keratinocytes, only place you can find melanocytes and Merkel cells
stratum spinosum
cells contain weblike system of intermediate filaments attached to desmosomes, melanin granules and Langerhans’ cells are abundant. tight connections created to form strong barrier
stratum granulosum
thin, 3-5 cell layers where drastic changes in keratinocyte appearance occurs, glycolipids produced for waterproofing, where cells “toughen up”
stratum lucidum
thin transparent band, few rows of dead keratinocytes, present only in thick skin. superficial to stratum granulosum
stratum corneum
outermost layer of keratinocytes, 3/4 of epidermis, functions include waterproofing, protection from abrasion and penetration, renders body relatively insensitive to biological, chemical, and physical assaults
papillary layer of the dermis
areolar connective tissue, superior surface contains peglike projections called papillae, which contain capillary loops, contain meissner’s corpuscles and free nerve endings for touch
reticular layer of dermis
80% of dermis, collagen fibers add strength and resiliency, elastin provides stretch and recoil
hypodermis
also subcutaneous later. deep to skin, composed of adipose and areolar connective tissue, not technically skin
melanin
yellow to reddish-brownish to black pigment responsible for dark colors. freckle/mole is a local accumulation
carotene
yellow to orange, most obvious in palms and soles of feet
hemoglobin
reddish pigment responsible for pinkish hue
merocrine gland
sweat glands for thermoregulation. secretions formed in vesicles and released by exocytosis, 99% water 1% electrolyte, some nitrogenous waste. 3-4 million in adult body
apocrine
sweat gland. modified merocrine, loses portion of cell when sweat is released, sweat contains proteins and lipids bacteria will feast upon. in axillary and pubic regions
ceruminous
sweat gland. modified apocrine glands in external ear canal that secrete cerumen
mammary
specialized apocrine sweat glands that release milk
holocrine
sebaceous gland. cells dividing, as they mature they burst releasing sebum
sebum
oily secretion
nails
scalelike modification of the epidermis on the distal, dorsal surface
hair
filamentous strands of keratinized cell produced by hair follicles. contains hard keratin which is tougher and more durable than keratin on skin. consists of medulla, cortex, and outermost cuticle
function of hair
warmth, detect presence of insects, guard scalp against physical trauma, heat loss, sunlight
vellus hair
pale fine body hair found in children and adult female
terminal hair
course, long hair of eyebrows, scalp, axillary and pubic regions
basal cell carcinoma
least malignant and most common, stratum basale cells proliferate and invade dermis and hypodermis, do not metastasize and can usually be cured by surgical excision
squamous cell carcinoma
arises from keratinocytes of stratum spinosum, grows rapidly and metastasizes if not removed
melanoma
cancer of melanocytes, most dangerous due to highly metastatic and resistant to chemo
partial thickness burn
only epidermis, redness swelling and pain
full thickness burn
appears grey white, cherry red, black, no edema or pain
contracture
when scar tissue is formed preventing movement
