Lab Chp. Four: The Integumentary System Flashcards
integumentary system
skin and its accessory organs
What are the functions of the skin?
- Thermoregulation (homeostatic regulation of body temperature)
- Cutaneous Sensations (pressure and temperature)
- Protection (Physical, chemical, and biological barrier)
- Excretion and absorption
- synthesis of vitamin D
keratinocytes
make keratin which forms a physical barrier
pigments
protection from harmful UV rays
lipids
insulation
calcitrol
active form of Vitamin D
why is the synthesis of vitamin d in the skin so important?
because it allows calcium to be metabolized
precursors to vitamin d are synthesized when the skin is exposed to ______
UV radiation
What are the two distinct layers of skin?
- Epidermis
2. Dermis
Epidermis
- Stratified squamous epithelium
- some principle cell types:
a) keratinocytes
b) melanocytes
keratinocyte
the predominant cell type in the epidermis, the outermost layer of the skin, constituting 90% of the cells found there.
melanocyte
are melanin-producing cells located in the bottom layer (the stratum basale) of the skin’s epidermis. produces pigment.
What are the layers of the epidermis, in order from top to bottom?
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
Stratum corneum
many layers of keratinized, dead epithelial cells; appear scaly and flattened; resists water loss, absorption, and abrasion
stratum lucidum
cells appear clea; nuclei, organelles, and plasma membranes no longer visible
stratum granulosum
three to five layers of flattened granular cells; contain shrunken fibers of keratin and shriveled nuclei
stratum spinosum
many layers of cells with centrally located, large, oval nuclei; develop fibers of keratin; cells becoming flattened in superficial portion
stratum basale
a single row of cuboidal or columnar cells; layer also includes melanocytes; frequent cell division; some cells become parts of more superficial layers
Apocrine sweat gland
becomes active at puberty
arrector pili muscle
causes hair to stand on end and goose bumps to appear
dermis
inner layer of skin
eccrine sweat gland
responds to elevated body temperature
Epidermis
general name of entire superficial layer of skin