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LEC 3 Integumentary System.pdf

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Health Sciences
Health Sciences 2300A/B
Jamie Melling

LEC 3: Integumentary System September-07-12 2:08 PM • Integumentary system- large organ that covers the body • Two components of skin epidermis(above) and dermis • Hypodermis is NOT part of the skin - fat and areolar tissue • Made up of almost entirely epithelial cells, organ must contain multipletissues • Portion of skin made up of one epithelial tissue -stratified squamous • Keratinized squamousepithelium , keratin is a small protein that gives it integrity and strength • Keratinocytes- carries melanin, pigment that gives colour to substance relates to colour of skin • Melanocytes are cuboidal epithelial cells that actually produce melanin rapidly, keratinocytes take-up melanin and spread it out • Melanin surroundsovertop of to protect • As tissues grows the deep keratinocytes are lost as well as tan • Merkel cells- nervous cell, exist in epithelial of the epidermis • Langerhanscells-macrophages , may exists near the middle to clean up tissue Layers • Stratum- "layer" • Active layer of epithelial , cells rapidly divide and pushed towards more superficial • layers as they die also known as "germ" layer- highly active and replicated • Spinosum is the largest in SIZE and made up almost entirely melanocytes all are attached to each other • Granulosum- cells undergo cell death b/c they become too far removed from an oxygen source that is only in the dermis. As they die they release lipid filled sacs, hydrophobic creates a water proofinglayer at granulosum • Lucidum only exists where there'sthick skin - palms and feet , everywhereelse layer above granulosum is a corneum • Corneum- dehydrated and stuck together- many layers of dead cells Lectures Page 1 DERMIS • Made up almost entirely of connective tissue • Lots of vessels within it, also makes leather from animals b/c its very strong • Skin must be strong, component within skin that gives it strength- dermis • As we age connective tissue in dermis loosens and flab takes over • Ink for a tattoo is placed on the dermis- won't stretch as fast • Wave like- increase surface area b/w epidermisand dermis( blood vessels), EPIDERMIS strengthens the attachment b/w epidermis and connective tissue Dermis 2 types of layers • Papillary - is not as strong as reticular region, both contain orientated (gathered together) collagen fibres, not as dense as reticular MORE VESSELS • Reticular- has an additionalfibre called the reticular fibre, more fibres, gives strength (ink for tattoo) • Damage to reticular destroys the vessels within the dermis and as a result bleeding, vessels regenerate as stretch marks (cells no longer function, becomes white, no longer vascular) • Scar will result from destruction of dermis MORE FIBRES • Nervousfibres all exist within dermis, scratch bleeds you've moved to dermis Go against pattern of fibres during surgery more apparent scar • Hypodermis- made up of fat, adipose tissue • Fat insulates the body, stored in different regions abdominal male, hips female Areolar tissue Fat tissue
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