Integumentary System
light-skinned races such as Caucasians
have approximately the same number of melanocytes as races with darker skins
cause of albinism
an inherited mutant gene for melanin
caused by an abrasion of the skin
a portal entry for microorganisms
determines the color of skin
amount of melanin produced by melanocytes in the skin
2 glands that produce sweat
apocrine and merocrine
region of the body where apocrine sweat glands are most numerous
axilla (armpit) and groin
a dietary substance that can contribute to the color of skin
carotene
the melanocytes in very dark skin
contain single, large, pigment granules
surrounds the nail and provides a barrier against infection
cuticle
the structure in hair that contains hard keratin
cuticle
may result in cold weather from reduced blood circulation through the skin
cyanosis, lack of oxygen in skin tissues
have greater melanin production
dark-skinned people
ways the skin promotes loss of excess body heat
dilation of dermal blood vessels, activation of eccrine sweat glands to release more sweat to skin surface, radiation, conduction, and convection
body heat is conserved
due to the contraction of smooth muscle in the walls of dermal blood vessels
will help cool the body
evaporation of sweat from the skin's surface
causes the skin to darken by stimulating the production of melanin
exposure to ultraviolet light
3 things that influence melanin production
genetics, exposure to sunlight, and pregnancy
grows for a period of time and then rests and grows again
hair
skin discoloration most likely to suggest physical trauma
hematoma
3 non-dietary substances that can contribute to the color of skin
hemoglobin, collagen, and melanin
skin color is the result of
heredity or genetic factors
glands that do not produce sweat
holocrine
a change that does not occur in aging skin
increased collagen
cause of "age spots"
increased melanocytes in certain areas of hands and face
3 changes that occur in aging skin
loss of elasticity, increased likelihood of skin infections, loss of fat from the hypodermis
same number in light-skinned and dark-skinned people
melanocytes
glands most responsible for cooling the skin
merocrine (aka eccrine) glands
skin discoloration most likely to result from anemia
pallor
most active growing region of the nail
nail matrix
modified structures derived from the stratum corneum
nails
protect the ends of fingers and toes
nails
nail technicians should not do this
pull back the cuticles aka eponychium
primary means by which body heat is lost
radiation
Eccrine sweat glands
respond primarily to elevated body temperature
is not a skin gland
salivary gland
associated with the hair follicle, aka holocrine glands, secretion is called sebum
sebaceous glands
types of skin glands
sebaceous, ceruminous, mammary
how eccrine sweat glands differ from sebaceous glands
secretion type, location in the body, sebaceous glands are associated with hair follicles, wheras sweat glands are not
skin change usually associated with aging
skin becomes wrinkled due to decrease in the number of elastin fibers
by reducing body temperature during hot weather
skin helps to maintain body homeostasis...
the activity of apocrine sweat glands
sometimes leads to body odor
produce the nail plate
specialized epithelial cells
layer of epidermis consisting of a single row of columar cells that undergo mitosis and includes pigment-producing melanocytes
stratum basale (germinativum)
the layer of epidermis that has no nuclei in its cells; flat, keratinized, dead cells
stratum corneum
the most superficial layer of the epidermis
stratum corneum
causes elderly persons to become less able to maintain stable body temperatures
sweat glands are replaced by fibrous tissue and their activity decreases as people age...
caused by an increase in body temperature
sweating
do not affect skin color
the quantity of melanocytes or amount of blood in the body
3 groups of people more likely to get skin cancer as they age
those frequently overexposed to the sun, fair-skinned blonds and redheads, and those who have a pre-existing mole
causes stretch marks
torn collagen fibers
contained in sweat
water, salts, and wastes
the hair shaft is pulled perpendicular to the skin surface, and movement of the hair follicle causes "goose bumps"
when the arrector pili muscle contracts
hair color resulting from a decrease in melanin
white
a decrease in the thickness of their subcutaneous fat layer
with aging, causes people to feel colder and usually need a higher temperature, especially in the winter