INTEGUMENTARY SYSTEM INTEGUMENTARY Presentations Minimum of 7 slides Will replace test All lab members must present to receive full credit Provide medicinal and layman terminology regarding the topic. LOTS of pics please…make them good One statistical bit of information regarding the topic. Members will grade each other and class will grade group! The Skin (Basic Characteristics) Waterproof Stretchable Washable Permanent-press Invisibly repairs small cuts, rips, and burns Guaranteed to last a lifetime with reasonable care Weighs on average between 9 and 11 pounds (approx. 7%-15% of total body weight) Measures between 1.5 and 4 mm thick Thick skin –Does not have hair follicles or oil glands One last interesting FACTOID about skin: Every square centimeter of skin contains… 70 cm of blood vessels, 55 cm of nerves, 100 sweat glands, 15 oil glands, 230 sensory receptors, and approximately 500,000 cells that are constantly dying and being replaced (you lose 40 lbs of cells within your lifetime) Function: Protection Structure: Composed dermis of two major regions: epidermis and Epidermis No Labeling YET!!! Composed of epithelial cells Not vascular Made up of 4 types of cells Consists of 4-5 distinct layers New epidermis is regenerated every 2545 days Cells of the Epidermis Epidermal Cells AKA: The Dendritic Cell 4 Types of Cells: Keratinocytes Produce keratin, waxy coating Melanocytes Synthesize pigment called melanin Protect cell from UV radiation Tactile Cell AKA Merkel cell) functions as a sensory receptor for touch Langerhans’ cells Macrophages that help to activate immune system Layers of Epidermis In thick skin (soles of feet and palms of hands) there are five layers (strata); everywhere else has four Deep to Superficial: Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (only present in thick skin) Stratum corneum Dermis Strong, flexible connective tissue Cell types: Fibroblasts Macrophages Mast cells White blood cells Binds the entire body together Your HIDE Vascularized Hair follicles, oil glands, and sweat glands 2 major layers: Papillary layer Reticular layer Papillary Layer Highly vascularized Borders the stratum basale of epidermis Touch and pain receptors On palms and soles, these papillae lie atop dermal ridges, which produce whorled epidermal ridges (fingerprints) Reticular Layer 80% of dermis layer Collagen binds water, helping to hydrate the skin Elastin fibers give skin elasticity The Hypodermis Known as subcutaneous tissue or superficial fascia Structure: Has more adipose than dermis Functions: Energy reservoir Thermal insulation Hypodermic Hypodermis Into injections subcutaneous tissue since highly vascular Subcutaneous Fat Distribution PIGMENTS of the SKIN Melanin = brown Carotene = orange Hemoglobin = red Carotene Yellow to orange pigment found in certain plant products Accumulates in stratum corneum and in adipose tissue of hypodermis Most obvious in palms and soles where S. corneum is thickest Hemoglobin Red pigment of red blood cells (RBCs) Since Caucasian people contain relatively small amounts of melanin, their skin is nearly transparent which allows hemoglobin’s color to shine through Sweat Glands Exist all over skin except nipples and part of external genitalia (more than 2.5 million/person) 2 types: Eccrine and apocrine Eccrine Sweat Glands Much more numerous Most abundant on palms, soles, and forehead Eccrine Sweat Glands Secretion-called sweat-is 99% water, with some salts, vitamin C, antibodies, traces of urea, uric acid, ammonia Also contains lactic acid, which is the chemical that attracts mosquitoes Normally of pH 4 to 6 Apocrine Sweat Glands Most common in armpit and anogenital regions Larger than eccrine glands Ducts empty into hair follicles Apocrine secretion has generally same composition as normal sweat, however it has fatty acids and proteins which makes it more viscous Odorless, however, when decomposed by bacteria on skin a “Body Odor” is created Ceruminous Glands Modified apocrine glands found in the lining of external ear canal Secrete sticky cerumen (earwax) Thought to deter insects (bitter flavor) and block entry of foreign particles Mammary Glands Specialized apocrine sweat gland that secretes milk Exist in both men and women Males – little mammary tissue Females – milk develops with increase of hormones when pregnant and after birth Prolactin Progesterone Estrogen Nails Modification of epidermis Corresponds to hoofs or claws of other animals Contains hard keratin (like hairs) Clear, hard derivative of stratum corneum Growth rate is 1 mm/week New cells added by mitosis in the nail matrix Growth zone at proximal edge of nail Structure: Nail bed is skin on which nail plate rests Hyponychium is epithelium of nail bed THE END TIME FOR THE PRESENTATIONS