1. Function and Dysfunction of the Integumentary System

2. Functions of the Integumentary System 1. Protection – chemical, physical, and biological barrier A. Chemical Barriers: –Melanin defends against UV –Skin secretions prevent infection: sebum: fatty acids w/ mild antibacterial and antifungal properties defensin and cathelicidins (antibiotics) made by wbc –Puncture membranes of bacteria Low pH (acidic) denature proteins High salinity dehydrate pathogens

3. Functions of the Integumentary System 1. Protection – chemical, physical, and biological barrier B. Physical Barriers : –Skin continuity –Hardness and thickness of keratin –Glycolipids made by s. granulosum waterproofs the skin SEM of keratin taken from thumb

4. Functions of the Integumentary System 1. Protection – chemical, physical, and biological barrier C. Biological Barriers : –Langerhan’s Cells and Macrophages activate the immune response –DNA has ability to absorb UV light and dissipate it into harmless heat “auras” captured with specialized equipment may be due to DNA vibrating at differing frequencies (not yet proven) Can we photograph the human “soul?”

5. Functions of the Integumentary System 2. Body temperature regulation –Dilation of dermal blood vessels (cool) –Constriction of vessels (conserves heat) –Evaporation of sweat cools the body pore

6. Functions of the Integumentary System 3. Cutaneous sensation – receptors detect touch, pain, and temperature –Meissner’s corpuscles and Merkel disks: located in papillary layer of the dermis detect lighter sensations –Pacinian corpuscles: located in the hypodermis detect deep pressure –Ruffini’s corpuscles: detect heat and changes in mechanics/movement –Hair follicle receptors: respond to touch as hair bends –Free nerve endings: sense pain and irritation

7. Functions of the Integumentary System 4. Metabolic functions –makes vitamin D from cholesterol in dermal blood vessels –Keratinocytes make enzymes that disarm cancer causing chemicals that penetrate skin 5. Blood reservoir –skin vessels store up to 5% of the body’s blood volume, to be used when needed by organs 6. Excretion – small amounts of Nitrogenous wastes are eliminated in sweat