a&p test 2 review

a&p test 2 review - Test 2 Study Guide Components...

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Test # 2 Study Guide Components of the Skin that form the cutaneous Membrane- Epidermis (or superficial epithelium) & Dermis (underlying are of the connective tissue) Functions of the Integumentary System Protection – underling tissues and organs against impact, abrasion, fluid loss and chemical attack Excretion- of salts, waters, and organic wastes by the integumentary glands Maintenance- normal body temperature through either insulation or evaporative cooling, as needed Synthesis- of Vitamin D 3 , a steroid that is subsequently converted to calcitrol, a hormone important to the normal calcium metabolism Storage- of lipids in adipocytes in the dermis and in the adipose tissue in the subcutaneous tissue Detection- of touch, pressure, pain, and temperature stimuli, and in the relaying of that info to the nervous system. Function of Skin’s epidermis- considerable mechanical protection and helps keep microorganisms out Type of tissue that forms the epidermis- Stratified Squamos Epithelium Name of cells that mostly make up the epidermis- keratinocytes. Thin Skin- covers most of the body surface and contains four layers of keratinocytes and is as think as the wall of a plastic sandwich bag. Thick Skin- on the palms of hands and soles of feet. Contains five layers of keratinocytes and is as thick as a paper towel. 4 layers of the skin. From bottom to top.
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stratum germinativum (stratum basale)- innermost epidermal layer. Hemidesmosomes attach this layer of cells to the basal lamina rhat separates the epidermis from the areolar tissue of the adjacent dermis. o The stratum germinativum forms epidermal ridges which extend into the dermis and are adjacent to the dermal papillae that project in the epidermis. o These ridges and papillae are significant because the the strength of the attachment is proportional to the surface area of the basal lamina: the more folds the, the larger the surface area becomes. Stratum Spinosum- 8 to 10 layers of keratinocytes bound together by desmosomes. Stratum Granulosum- grainy layer. 3 to 5 layers of keratinocytes. By the time cells reach this layer they have stopped dividing and started making keratin. Stratum lucidum (only in thick skin)- covers the stratum granulosum. Cells are flattened, densely packed, filled with keratin. Stratum corneum- Exposed surface of the skin. 15 to 30 layers of keratinized skin. Function of following cells in the epidermis Keratinocytes – most abundant epithelial cells. Form several layers and contain large amounts of the protein keratin. o Keratin- the tough, fibrous protein component of nails, hair, calluses, and the general integumentary surface Merkel Cells- found on skin surfaces that lack hair. Are scattered among the cells of the stratum germinativum. When compressed they release chemicals that stimulate sensory nerve endings. Melanocytes- Pigment cells that cause the brown color of skin. Distributed
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This note was uploaded on 11/18/2009 for the course BIO 121 taught by Professor Morris during the Spring '09 term at Widener.

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a&p test 2 review - Test 2 Study Guide Components...

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