Integumentary System Flashcards
considered as the true covering surface of the body
integument skin
largest organ of the vertebrate body
integument skin
15-16% of total human body weight
integument skin
covers area of 1.6 m^2 (17.5ft)
for average women
covers area of 2.0 m^2 (21.5ft)
for average men
about 1 to 2 mm thick
skin
0.5 mm thick on the _
eyelids
6mm thick on the _
palms and soles
how many dead skin cells are shed in a lifetime?
40kg (88 lb)
how many nerve endings, hairs, muscle, sweat glands, oil glands, blood vessels, heat receptors, cold receptors and pressure-sensing receptors are contained in one sq cm of human skin?
200 nerve endings, 10 hairs and muscles, 100 sweat glands, 15 oil glands, 3 blood vessels, 12 heat receptors, 2 cold receptors, 25 pressure-sensing receptors
7 functions of epidermis
1) covering and protection
2) secretion of substances
3) excretion of metabolic wastes
4) sensation and regulation of temperature
5) storage of reserved food
6) nourishment
7) respiration (in amphibians)
thin, upper part of the skin composed of stratified squamous layer of epithelial tissue
epidermis
10 to 30 cells thick, about as thick as a page
epidermis
outermost layer composed of dead cells packed with keratin
stratum corneum
tough, water proof protein
keratin
translucent layer, composed of flat dead and non-nucleated cells
stratum lucidum
composed of keratohyaline granules
stratum granulosum
prickle cell layer, composed of langerhans cells
stratum spinosum
inner layer, composed of actively dividing cells
stratum germinativum (basale)
90% of epidermal cells, produce keratin
keratinocytes
8% of epidermal cells, produce melanin
melanocytes
brown pigment, absorbs uv rays
melanin
capable of trapping antigen in the skin
langerhans cells
make contact with the ending of a sensory neuron
merkel cells
largest layer of the skin
dermis
lower, thicker part of the skin composed of fibrous connective tissue containing collagen and elastic fibers
dermis
contains muscle fibers, glands, pigment cells, blood vessels and sensory nerves
dermis
15 to 40 times thicker than thee spidermis
dermis
provides structural support for the epidermis and as matrix for many nerve endings, muscles and specialized cells in the skin
dermis
consists of areolar connective tissue, forms the dermal papillae, some contains tactile receptors called Meissner’s corpuscles
papillary region
consists of dense, irregular connective tissue, attached to underlying organs
reticular region
for light touch
meissner’s corpuscles
for deep pressure
pacinian corpuscles
for pain and light touch associated with hair follicle
naked nerve endings
for heat
corpuscles of ruffini
for cold
end bulb of krause
composed of fat-rich adipose cells
subcutaneous layer
acts as shock absorbers
subcutaneous layer
provides insulation to conserve body heat
subcutaneous layer
glands originating from the epidermal cells that have invaginated into the dermis
cutaneous or dermal glands
true glands, not destroyed during secretion, most sweat glands
merocrine glands
part of the cell is destroyed that go with the secretion, mammary gland and some sweat glands
apocrine glands
the entire cell goes with the secretion, but a new cell is produced to replace it, sebaceous or oil gland
holocrine glands
watery substance, sweat glands
serous glands
oily substance called sebum
sebaceous glands
substance with mucin
mucous glands
non living structures found on the outer layer of the epidermis
keratinized derivatives
include the hair of mammals, feathers o birds, nails or claws, beak, scales of reptiles, scutes of turtles and true horns (hollow)
keratinized derivatives
non living structures originating in the dermis and found on the outer layer of the epidermis, include the false horns (solid), plates of turtles and scales of fishes
dermal derivatives
