BIO Ch 5- The Integumentary System.docx - 1 Biology: Human...

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1Biology: Human Anatomy and PhysiologyChapter 5: The Integumentary System5.1 Structure of the SkinIntegumentary systemSkin, hair, oil and sweat glands, nails, and sensory receptors.What are thefunctionsof theintegumentary system?1.Regulate body temperature2.Stores blood3.Protects body from external environment4.Detects cutaneous sensations5.Secretes and absorbs substances6.Synthesizes vitamin DSkin or “cutaneous membrane”Largest organ of the body in weightConsists of:1.Epidermis2.DermisPapillary layerReticular layer3.Subcutaneous LayerEpidermis:Avascular, epithelial tissueThe epidermis iscomposed of keratinized stratified squamous epithelium.It contains four principal types of cells1.Keratinocytes2.Melanocytes3.Intraepidermal macrophages “Langerhans”4.Tactile epithelial cells “Merkel”What arekeratinocyte?These are epidermal cells found in the epidermis, it makes up about 90% of the cellsThey produce a protein called keratin and lamellar granules which release a water-repellent thatdecreases water entry and loss and inhibits the entry of foreign materials.What isKeratin?This is a water resistant fibrous protein that helps protect the skin and underlying tissues fromabrasion, heat, microbes and chemicals
2What aremelanocyte?Pigmented cells that synthesize melanin.What isMelanin?This is a yellow-red or brown-black pigment that contributes to skin color and absorbs damagingUV lights.What areintraepidermal macrophagesor “Langerhans cell”Arise from red bone marrow and migrate to the epidermis.Function in the immune response to protect against microbes tha tinvade the skin.Tactile epithelial cellsorMerkel cellLocated in the deepest layer of the epidermisThey have contact with the sensory neuron (nerve cell); these detect touch sensationEPIDERMIS:What are the5 layersor strata of theepidermis?1.Stratum Basaleor stratum germinativumDeepest layerof the epidermis which is a single row of cuboidal or columnarkeratinocytes, and attaches to the basement membrane by hemidesmosomesContainsepidermal ridges (these form fingerprints)Containsbasale cells(stem cells), melanocytes, and tactile cells (merkel cells)Stem cells continually undergoing cell division (mitosis) to produce new keratinocytesKeratinocytes:Produce keratin which is a tough insoluble protein found in hair nails, and othertissues.Helps to protect the skin and underlying tissue against abrasion.2.Stratum SpinosumSuperficial to the stratum basaleKeratinocytes arranged in 8-10 layers bound bydesmosomesContains projections of melanocytes and macrophages (langerhan cells)3.Stratum granulosumThis is the middle layer of the epidermisConsists of three to five layers of flattened keratinocytes.

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Term
Fall
Professor
Allan Kew
Tags
Stratum Corneum, skin disorder, sweat gland

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