ch5 Flashcards
epidermis
the superficial layer of the skin consisting of stratified squamous keratinized epithelium
dermis
the deeper layer of skin consisting of loose and dense irregular collagenous connective tissue
hypodermis
they layer of adipose tissue deep to the skin; also known as the subcutaneous tissue
eccrine sweat glands
glands in the skin that produce watery sweat as part of the body’s thermoregulatory mechanism
apocrine sweat glands
sweat glands found in the axillae, anal and areola that secrete a thick sweat that is rich in proteins. they become active at puberty and create odor when bacteria feeds on secretions.
functions of the integumentary system
protection, sensation, thermoregulation, excretion, vitamin D
excretion
eliminating wastes and toxins from the body
negative feedback loop for control of body temp
if temp is too high, thermoreceptors in the skin detect the inc in temp and send a message to the hypothalamus. the phyothalamus stimulates sweating. when temp returns to normal thermoreceptos stop sending the signal and the hypothalamus stopping the signal to sweat.
If the body temperature drops below the normal range, usually due to cold environmental conditions, the thermoreceptors in the skin detect the decrease in body temperature below the normal range and relay this to the hypothalamus. The hypothalamus stimulates the effector to respond by vasoconstriction (blood vessels in the dermis narrow, or constrict, reducing the amount of blood flow which limits the heat lost to the
environment.) Blood is also redirected to deeper tissues.
Layers of the epidermis (top to bottom)
Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale.
Thick skin has all 5 layers, thin skin has 4 layers (it does not have the
stratum lucidum.) Remember the mnemonic (Come Let’s Get Sun
Burned.) Thick skin is found on the palms of the hands and soles of the feet and does not have hair follicles.
keratinocytes
make up 95% of the epidermis. these cells manufacture keratin which is tough and protects the epidermis from mechanical damage and also makes the skin water resistant.
stratum basale
lowest layer of the epidermis where most mitosis takes place
stratum spinosum
thickest layer of the epidermis
stratum granulosum
cells fill with keratin in this layer
stratum lucidum
only found in thick skin
stratum corneum
top layer - takes 40-50 days for cells to migrate to this layer
dendritic cells (langerhans)
phagocytes of the immune system that protect skin and deeper tissues
Merkel cells
oval cells in the stratum basale that detect light touch and discriminate shapes and textures
melanocytes
melanin producing cells
callus
place where additional layers of the stratum corneum have formed in either thick of thin skin in response to repetitive pressure
dermis
deeper layer of the skin consisting of loose and dense irregular collagenous connective tissue. consists of the papillary layer and the reticular layer
lamellated corpuscles (pacinian)
sensory receptors located in the reticular layer of the dermis that detect pressure and vibration stimuli. resembles layers in a sliced onion.
epidermal ridges
folded patterns of the epidermis in thick skin that enhance gripping ability and also produce fingerprints.
melanin
pigment that is produced in melanocytes and ranges in color from brown-black to orange-red and gives UV protection
carotene
orange pigment found in carrots sweet potatoes etc
