47 terms

ZOO 331 Chapter 5 Integumentary System

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epi
upon, outside
keratinocytes
produce fibrous protein keratin
tightly connected by desmosomes
melanocytes
found in the deepest epidermis
produces the pigment melanin which protects the apical surface of the keratinocyte nucleus from UV damage
stratum basale
firmly attaced to the dermis
single row of stem cells of keratinocytes
actively mitotic
25-45 days to reach the surface
stratum spinosum
cells contain prekeratin filaments attached to desmosomes
stratum granulosum
cells flatten, nuclei and organelles disintegrate
cells fill with keratin and release water resistant glycolipid
stratum lucidum
found only in thick skin (bottom of feet, palms)
a few rows of flat, dead keratinocytes
stratum corneum
20-30 rows of dead cells that are keratinized and lack a nucleus
protect against water loss, abrasion, and penetration
apoptosis
controlled cellular suicide
nucleus and organelles break down, plasma membrane thickens
dermis
made of connective tissue, contains nerve fibers, blood and lymphatic vessels, contain hair follicles, and the oil and sweat glands of the epidermis
two layers (papillary and reticular)
dermal papillae
capillary loops, free nerve endings (pain receptors), found just below the epidermis in the humps
papillary layer
dermal papilla sit on top of dermal ridges that cause epidermal ridges (fingerprints)
reticular layer
80% of dermal thickness
elastic fibers provide stretch- recoil properties
made of collagen fibers that provide strength and resiliency, protects against penetration of scrapes into dermis
cleavage lines
collagen running parallel to skin surface, useful in surgical incisions
flexure lines
dermis tightly secured to deeper structures, visible on hands wrists, fingers, soles, toes (palm reading)
stretch marks
extreme stretching of the skin
dermal tears leave scars
hypodermis
(subcutaneous layer) made of adipose connective tissue that allows independent movement of skin from underlying structure, padding, and thermal insulation
skin color
three pigments contribute to skin color
melanin, carotene, and hemoglobin
melanin
produced in melanocytes, same relative number of cells in all people
color differences due to the amount and form of melanin
sun exposure stimulates melanin production, shields DNA of viable skin cells
albinism
lack of melanin production
vitiligo
melanocytes destroyed (autoimmune disorder)
michael jackson
tattoos
ink inserted all the way through the epidermis to the dermis
reticular/papillary layer
carotene
yellow to orange pigment (carrots)
accumulates in stratum corneum and hypodermis
hemoglobin
pinkish hue of fair skin
found in capillaries and blood
Cyan
blue
cyanosis
blue skin color, low oxygenation of hemoglobin
jaundice
liver disorder, buildup of bilirubin(pigment) in the blood that causes a yellow color
derivatives of the epidermis
hair and hair follicles
fingernails/toenails
sweat glands
sebaceous (oil) glands
hair
dead keratinized cells
protection from insects on skin, heat loss, sunlight, and filter large particles (nose)
demodex folliculorum
dust mite that lives in the hair follicle
nails
modifications of the epidermis, protective, contains hard keratin
nail matrix is responsible for nail growth
onychomycosis
fungus of the toenail
eccrine(merocrine sweat glands)
most numerous, abundant on palms soles, and forehead
ducts connect to pores
function in thermoregulation
sweat (99% water, NaCl, metabolic waste)
secreted by exocytosis
apocrine sweat gland
axillary and anogenital areas
sweat, fatty substances, and proteins
viscous, milky or yellowish
bacterial interaction creates odor
release product by exocytosis
ceruminous glands
external ear canal, secrete cerumen (earwax)
mammary glands
secrete milk
sebaceous (oil) glands
widely distributed but not in palms or soles
secrete into hair follicles
secrete sebum (holocrine secretion, bactericidal, softens hair and skin)
acne
abnormal desquamation of keratinocytes that line sebaceous follicle>micro plug
increased androgens at puberty
propionibacterium acnes> induce a local inflammatory response, stimulate sebum production
functions of the integumentary system
skin secretions-low pH retards bacterial multiplication, secretions kill bacteria
melanin-defense against UV radiation damage
stratum corneum cells surrounded by glycolipids-block most water and water soluble substances
body temperature regulation, integumentary system
blood vessel constriction or dilation, sweating, capillaries dialate to lose more heat
cutaneous sensations
receptors detect temperature, touch, and pain
metabolic functions
synthesis of vitamin D precusor
excretion
nitogenous wastes and salt through sweat
skin cancer
most skin tumors are benign and do not metastasize
risk factors- over exposure to UV radiation, frequent irritation of skin
basal cell carcinoma
least malignant, most common
stratum basale cells proliferate and slowly invade dermis and hypodermis
cured with surgical excision in 99% of cases
squamous cell carcinoma
second most common, keratinocytes of stratum spinosum, does metastasize
usuallly scaly reddened papule on scalp, ears, lower lip, and hands
good prognosis if treated by radiation therapy or removed surgically
melanoma
cancer of melancytes-highly metastatic
treated by wide surgical excision and immunotherapy
key to survival is early detection