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Intriguing Integumentary System The Skinny on the Skin System Anatomy *Skin *Sweat *Oil Glands *Hair *Nails System Physiology-PROTECTION • Mechanical Damage (Injury) • Chemical Damage (acids, bases) • Bacterial Damage • UV Radiation (melanin) • Thermal Damage (temperature receptors) • Drying Out (outer layer is hard) System Physiology Temperature Regulation *Rich blood supply and sweat Excretion *Urea, salt, and water System Physiology Production of Proteins *Vitamin D Sensory Receptors *touch *pressure *pain *temperature The Skinny on the Skin 1. Epidermis – Outer layer – Stratified Squamous 2. Dermis – Fibrous Connective - Blister – When the two layers get rubbed and separate Subcutaneous Tissue • Adipose anchors skin • • to organs Shock absorber Insulates deeper tissues I. Epidermis • Avascular-no blood • supply (shaving) Made of up to 5 layers Skin Layers A. Stratum Corneum • 20-30 cell layers thick • Outer layer • DEAD • Contains Keratin fibers (water repellant) • Constantly worn away • You get a new epidermis every 35-45 days More Skin Layers B. Stratum Lucidum Only in hairless skin Extra thick Palms of hands, soles of feet C. Stratum Granulosum *Cells die D. Stratum Spinosum More Skin Layers • • • • • • Stratum Basale Deepest Cell Layer of Epidermis Constantly in Cell Division (millions of new cells daily) Cells get pushed to surface as they grow Melanin is in this layer Receives nourishment from dermis by diffusion Diagram of the Skin Layers F. Tanning • Melanocytes produce • • melanin in the stratum basale Sunlight stimulates the melanocytes to produce melanin (brown color) Melanin shields the nucleus from the sun’s UV rays Basal Cell Carcinoma • Happens when cells in stratum basale divide uncontrollably • Usually Slow growing and easy to remove Squamous cell carcinoma • Happens in stratum spinosum • Grows rapidly • Needs to be removed and followed with radiation Malignant Melanoma • Cancer of melanocytes • 50% survival rate • Needs removal, chemotherapy • Can spread to other parts Signs that a mole might be Cancerous A. Asymmetry – mole is not symmetrical B. Border – jagged borders C. Color – multiple colors D. Diameter – larger than ¼ inch (size of pencil eraser) E. Evolution – mole is evolving or changing II. Dermis -Strong and Stretchy (hide) A. Papillary layer -Upper layer of dermis -Dermal papillae – give nutrients to epidermis -Ridges form Fingerprints: increase gripping, friction- hands/feet --pain and touch receptors live here Dermis - Cont B. Reticular Layer -Deepest layer of dermis -Contains BLOOD VESSELS! -Sweat and Oil glands -Deep pressure receptors -Phagocytes to eat bacteria -Collagen fibers-keep skin hydrated -Elastic fibers-decrease with age - wrinkles Skin Appendages Sebaceous Glands (Oil) • All over the body, EXCEPT palms and soles of • • the feet Usually empty into a hair follicle Make SEBUM: Oil and fragmented cells -Lubricant: Keeps skin soft -Prevents hair from being brittle -Chemicals that kill bacteria • Yuk -Whitehead--when oil gland is blocked -Blackhead--dries and darkens II. Sudoriferous Glands (SWEAT) A. Eccrine -Produces sweat (water, urea, salt, uric acid) -Acidic (pH 4-6, inhibits bacteria -Found all over body -Help Regulate heat B. Apocrine -Found in Genital and Axillary regions -Large -Secrete Fatty Acids and proteins also -ODORLESS, but stinks when bacteria eats it! First Degree Burns Only Epidermis Damaged Second Degree Burns Epidermis and Upper Dermis Damaged Third Degree Burns Destroys whole thickness of skin