Chapter 5: Integumentary
1st 11 pages of Chapter 5: Integumentary System in Fundamentals of Anatomy and Physiology, Martini
Terms
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- Langerhans cells
- located in the Stratum Spinosum; participate in immune response by stimulating a defense against: microorganisms that manage to penetrate superficial layers of epidermis and superficial skin cancers.
- Keratinocytes
- dominate epidermis; body's most abundant epithelial cells; form several layers; contain large amount of the protein keratin.
- Two pigments found in epidermis
- carotene and melanin
- Stratum Corneum
- at the exposed surface of both thick and thin skin; contains 15-30 layers of keratinized cells; water resistant, but NOT waterproof
- Sensible Perspiration
- produced by active sweat glands
- What determines skin color?
- epidermal pigmentation and dermal circulation
- Why does swimming in fresh water for an extended period cause epidermal swelling?
- Fresh water is hypotonic in relation to skin cells, so water will move into the cells by osmosis, causing them to cell
- Stratum Germinativum
- location of stem cells that divide and replace; innermost epidermal layer; also called stratum basale; hemidesmosomes attach the cells of this layer to the basal lamina that separates the epidermis from the areolar tissue of the adjacent dermis; forms epidermis ridges
- Thick layer of Epidermis
- Contains 5 layers of kerotin; occurs on the palms of the hands and the soles of the feet; about as thick as a paper towel
- What causes dandruff?
- excessive shedding of cells from the outer layer of skin in the scalp, the stratum corneum
- blister
- fluid acculates in pocket when damage breaks the connection between superficial and deeper layers of epidermis
- Stratum Lucidum
- In the thick skin of the palms and soles, a glassy, clear layer covers the stratum granulosum; cells flattened, densely packed and filled with keratin
- If a splinter penetrates to the third layer in the palm, what layer of epidermis is the splinter lodged in?
- The stratum granulosum layer
- keratinocyte process in the dermis
- takes 15-30 days for the stratum germinativum to the stratum corneum; exposed to chemicals that shrink cytoplasm and leave the cytoskeletal elements and desmosomes intact; some of the cells continue to divide in the Spinosum increasing the thickness of the epithelium; keratinocytes displaced from spinosum in the granulosum, most have stopped dividing and begin making keratin and keratohyalin; as the keratin fibers develop, the cells grow thinner and flatter and their membranes thicken and become less permeable, keratohyalin forms dense cytoplasmic granules that promote dehydration of the cell as well as aggregation and cross-linking of the keratin fibers, nuclei and other organelles then disintegrate, and the cells die; further dehydration creates a tightly interlocked layer of cells that consist of keratin fibers surrounded by keratohyalin; become 15-30 layers of protective superficial layers of cells filled with keratin called the stratum corneum
- Insensible perspiration
- water from interstitial fluids slowly penetrates the surface, to be evaporated into the surrounding air; lose roughly 500mL each day this way; unable to see this water loss
- Layers of Epidermis
- The strata: the stratum germinativum, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
- Thin Layer of Epidermis
- contains four layers of keratinocytes and is about as thick as the wall of a plastic sandwich bag
- Integumentary System
- accounts for about 16% of total body weight; first defense against an often hostile environment
- Merkel Cells
- specialized cells located in skin surfaces that lack hair
- Stratum Granulosum
- superficial to the spinosum; grainy layer; consists of 3-5 layers of keratinocytes displaced from the spinosum; cells have stopped dividing and begin making large amounts of the proteins keratin and keratohyalin
- 2 Components of Cutaneous Membrane
- Epidermis and Dermis
- Keratin
- a tough, fibrous protein; the basic component of hair and nails in humans
- 2 Major components of Integumentary System
- Cutaneous Membrane and Accessory Structures
- Stratum Spinosum
- Consists of 8-10 layers of kertinocytes; means "spiny layer"; one of daughter cells moves out of germinativum to this layer
- Keratohyalin
- forms dense cytoplasmic granules that promote dehydration of the cell as well as aggregation and cross-linking of the keratin fibers.
- Would sanding the tips of your fingertips permanently remove prints?
- Not permanently, the ridges are determined by the arrangement of tissue in the dermis, which is not permanently affected by sanding
- General functions of skin and subcutaneous layer
- Protection, Excretion, Maintenance, Synthesis, Storage and Detection
- Epidermis
- superficial epithelium; stratified squamous epithelium