Annotated-Module%204%20Ingegumentary%20outline%20worksheet%20%282%29.pdf

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Anatomy and PhysiologyChapter 5: Integumentary SystemI. IntroductionoThe three layers of the skin are:1. Epidermis2. Dermis3. HypodermisoThe two primary functions of the integumentary system are:1. Protection of inner organs and tissues2. Vital in homeostasisII. Layers of the SkinA. EpidermisFunctions: protection, waterproof, prevent infection, protect against UV,protect from mechanical injury.Keratin.1. What is keratin?: intercellular, fibrous protein that gives hair, nails, and
skin hardness and water resistance.2. How is keratin made?: Through a process called keratinization, whichinvolves the hardening of cells when strands of tough, fibrous, waterproofkeratin proteins are synthesized and stored within a cell.Five Layers of the Epidermis1. Stratum basaleoCharacteristics/functions: Deepest layer, Single layer of basal cells:cuboidal-shaped stem cell that is the precursor ofkeratinocytes, Cells divide here (constantly going throughmitosis), move up and out and eventually die(stratum corneum), Cell membrane of older basal cells thicken(keratinization), Develop desmosomes that fasten to each other(waterproof)oContains these cells:1. Precursors of keratinocytes are called ___Basal________cells.2. Pigment-producing cells are called __Melanocyte__________.3. Sensory cells are called ___Merkel_____________.2. Stratum spinosumoCharacteristics/functions: Thickest layer, Contains desmosomes(“spiny”), Eight to 10 layers of keratinocytes, Langerhans cell: acts asmacrophage – destroys bacteria, foreign particles, and damaged cells,Keratinocytes begin to synthesize keratin and release a water-repellingglycolipid (makes skin waterproof).oContains these cells:
1. Eight to 10 layers of _____keraniocytes______________. Atthis timethese cells release a ____glycolipid______ thatmakes skin waterproof.2. Macrophage cells are called __langerhans__________.3. Stratum granulosumoCharacteristics/functions: Pushed up cells from stratum spinosum,Cells become flatter, membranes thicken, and they produce a lot ofkeratin and keratohyalin (“grainy”), Nuclei and other cellular organellesdisintegrates as cell dies – leaving keratin, keratohyalin, and cellmembrane.oThe cells become __flat______ and the cells produce a lot of____keratin________ and ____keratohyalin____________which appears“grainy” and gives this layer it’s nameGRANulosum.4.Stratum lucidumoCharacteristics: Present only where skin is thick (palms, soles, anddigits), Composed of dead, flattened keratinocytes, Densely packed,waterproof.oPresent only where skin is thick like: palms, soles, and digits.oComposed: dead, flattened keratinocytes.5. Stratum corneumoCharacteristics/functions: helps prevent penetration of microbes,prevents dehydration of underlying tissues, provides mechanicalprotection for underlying skin layers. Most superficial layer, exposed tooutside environment, Fully keratinized (cornification) layer (dead cells),15 to 30 layers of cells
oThis layer is replaced every ___4____ weeks.

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Term
Fall
Professor
Jane Chapman
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