Transcript Chapter 4
Chapter 4 Integumentary System Basic Skin Functions 1. 2. Keeps water and other molecules in Keeps water and other molecules out * Keratin – water-proofing protein 3. Insulates 4. Cushions deeper organs 5. Protects from: a. Mechanical damage – cuts/bumps b. Chemical – acids and bases c. Thermal d. UV e. Bacteria 6. 7. 8. 9. Regulates heat loss with a capillary network and sweat glands Mini excretory system (urea, salts, water) Manufactures proteins and vitamin D Sensory receptors Structure of the Skin Two Layers a. b. Epidermis Dermis • Deep to the dermis is the Hypodermis or subcutaneous layer • This Layer is deep to the dermis but is not part of the skin - anchors A. Epidermis • 5 layers • Avascular – no blood • Cells are made in the bottom layer and move up • New epidermis – 25 to 45 days Melanin • Skin pigment • Yellow to brown/black • Produced by melanocytes in the bottom layer • Tanning occurs when melanocytes produce more pigment • Melanin pigment umbrella over nuclei • Freckle – local concentration of melanin B. Dermis • Strong stretchy envelope that holds the body together • Two layers • Fingerprints originate from projections in this layer • Deepest layer – blood vessels (temperature), sweat, oil glands • Has collagen – toughness of the dermis • Elastic fibers – elasticity of the skin - wrinkles when lost Skin Color • Is caused by three pigments 1. amount and kind of melanin 2. Amount of carotene – orange 3. Amount of oxygen in hemoglobin (when there is a lot of oxygen – red) (when there is little oxygen – blue) Affected by emotional stimuli and disease 1. 2. 3. 4. 5. Erythema – redness Pallor – pale Jaundice – yellow – liver Bruises – blood vessels damaged and blood leaks out Cyanosis – blue cast to skin - not enough oxygen Appendages of the Skin I. Cutaneous glands (Exocrine) – give off a. Sebaceous (oil) glands 1. empty on to a hair follicle 2. produce sebum – lubricant – kills bacteria 3. Duct blocked - zit b. Sweat glands 1. sweat – clear secretion that is primarily water plus NaCl, vitamin C, traces of metabolic waste (urea) 2. Important for heat regulation 3. Hot days – lose up to 7L II. Hair and Hair Follicles – produce hair a. b. c. d. Protective functions Root – part in the follicle Shaft – part growing out of the skin Made of dead cells full of keratin III. Nails a. b. c. Scalelike, modification of the epidermis Free edge, body, root Made of dead cells full of keratin Homeostatic Imbalances of the Skin There are 1000’s 1. Infections and Allergies Athlete’s Foot • Itchy red peeling condition between the toes • Caused by: Fungus Athlete’s Foot Boils • Inflammation of the hair follicles and sebaceous glands • Staphylococcus aureus • Caused by: inflammation of a follicle Boils Carbuncles • Composite boils • Caused by: bacteria infection Carbuncles Carbuncles Cold Sore • Small fluid filled blisters that itch and sting • Caused by: Herpes simplex infection • Virus in cutaneous nerve • Dormant until emotional upset, fever, or UV light Cold Sore Contact Dermatitis - Poison Ivy • Itchy redness, swelling and blistering • Caused by: Exposure to chemicals Poison Ivy Impetigo • • • • Pink water filled lesions Around mouth and nose Yellow crust and rupture Caused by: Highly contagious staph infection • Common in elementary kids Impetigo Psoriasis • • • • • Chronic condition Reddened epidermal lesions Dry silvery scales Can be disfiguring Caused by: cause is unknown – hereditary? • Attack often triggered by trauma, infection hormonal changes, stress Psoriasis Acne • Caused by: blockage in the hair follicle 2. Burns • Skin is as thick as a paper towel • Damage affects all other body systems • Burn – tissue damage and cell death caused by heat, UV radiation, chemicals Two Life Threatening Problems 1. 2. Body loses precious supply of fluids Infection Rule of the Nines • Estimates fluid loss • 11 areas of the body, 9% each, 1% area around the genitals Burn Classification First Degree • • • • Epidermis only Red/swollen Re-growth – cells still ok Partial thickness burn Second Degree • • • • Epidermis and top of dermis Blisters Re-growth – cells still ok Partial thickness burns Third Degree • • • • Full thickness burn Area blanched or blackened Nerves destroyed No re-growth - graft Burns are Critical if: • More than 25% of the body has second degree • 10% had third degree • Third degree on face, hands or feet Skin Cancer Basal Skin Carcinoma Squamous Cell Carcinoma Melanoma The End