5 Integumentary Powerpoints

5 Integumentary Powerpoints - General Functions of the...

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General Functions of the Integumentary System Protection from mechanical injury Physical protection of pathogen entry Chemical prevention of pathogen entry Sensation Thermoregulation Metabolic functions Looking good
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Basic Skin Structure The skin has 2 main layers: 1. The superficial, avascular epidermis ( epi means “above” and dermis means “skin”) consisting of 4-5 layers of epithelial cells resting upon a basement membrane. 2. The deep, vascular dermis consisting of fibrous connective tissue. Contains multiple blood vessels, and the accessory appendages.
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The Epidermis Keratinized stratified squamous epithelium. Avascular. Consists of 4 distinct cell types arranged in 4 or 5 distinct layers. Epidermal cell types: 1. Keratinocytes ( structure ) 2. Melanocytes ( pigment ) 3. Merkel cells ( sensation ) 4. Langerhans’ cells ( phagocytes - immune defense ) Yellow arrow indicates the epidermis of thick skin
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Keratinocytes Most numerous epidermal cell – found in all layers of the epidermis. Chief function is the production of keratin – a tough fibrous protein that gives strength and confers a lot of protective ability. Tightly connected to one another by desmosomes. Provides continuity, strength, and protection. Is the reason skin flakes off in sheets rather than as individual cells. Almost all of the epidermal cells in this slide are keratinocytes
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Keratinocytes New cells are continuously made in the deepest layer pushing the older cells up. As the keratinocytes move farther from the deepest layer, they make the keratin that eventually dominates their cell contents. When they have reached the upper layer, they are nothing more than scale-like bags of keratin.
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Melanocytes Spider-shaped epithelial cells that synthesize the protein pigment melanin. Found in the deepest layer of the epidermis. Melanin is made and then packaged into membrane-bound granules called melanosomes. Granules are transferred to the keratinocytes in the 2 deepest layers of the epidermis. Arrows indicate 2 melanocytes.
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Melanocytes Melanin granules accumulate on the “sunny side” of the nucleus of the keratinocytes. Would that be the apical or the basal side? Melanin granules protect the DNA within the nucleus from being damaged by the ultraviolet radiation from the sun.
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Skin Types 1. Thick Skin Found on soles of feet and palms of hands and corresponding parts of fingers and toes. Contains 5 epidermal
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This note was uploaded on 02/26/2011 for the course BIO 107 taught by Professor Smith during the Spring '11 term at NE Texas CC.

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5 Integumentary Powerpoints - General Functions of the...

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