Published on January 4, 2008
Integumentary System: Integumentary System Skin Functions: Skin Functions Protection Regulates body temperature Regulates water loss Sensory perception Chemical synthesis Protection against infection Types of Membranes: Types of Membranes Serous Membranes Line body cavities that have no opening to the outside Secrete a watery fluid called serous fluid that lubricates surfaces. Membranes: Membranes Mucous Membranes Line cavities and tubes that open to the outside Membranes: Membranes Synovial Membranes Form the inner lining of joint cavities Secrete a thick fluid called synovial fluid Cutaneous Membrane: Cutaneous Membrane Also known as the skin Specialized Epidermal Cells: Specialized Epidermal Cells Keratinocytes - waterproofs the skin Melanocytes - produce melanin Everyone has about the same number of melanocytes. Skin Color: Skin Color Genetic Factors All humans have the same number of melanocytes How much melanin they produce is controlled by several genes Lack of pigment is called albinism Environmental Factors Exposure to sunlight Tissue Layers: Tissue Layers Epidermis Upper layer of the skin Dermis Has a blood supply Contains connective tissue and muscle Attached to the body by a basement membrane Epidermal Layers: Epidermal Layers Stratum corneum - nuclei and organelles are destroyed by lysosomes and the cells fill with keratin Stratum lucidum - only found in the palms and soles of feet Stratum granulosum - cells start to become keritanized Epidermal Layers: Epidermal Layers Stratum spinosum - as these cells mature they lose the ability to divide Stratum basale (germinativum) - the reproductive layer of the epidermis. Push new cells to the surface Dermis: Dermis 1-2 mm thick, 3mm thick on the soles and palms Skin is thicker in males than females Dermal Layers: Dermal Layers Papillary layer Loose connective tissue Finger-like projections capillary network found here. Temperature regulation Dermal Layers : Dermal Layers Reticular layer Dense connective tissue (mostly collagen) Responsible for the mechanical strength of the skin Dermal Layers: Dermal Layers Superficial Facia Loose connective tissue - glues skin to the body Subcutaneous Fat: Subcutaneous Fat Insulates the body, provides padding to feet and hands Accessory Organs: Accessory Organs Hair - protection, sexual attraction Hair follicles - once killed they do not regenerate Arrector pilli muscle - causes the hair to stand on end Accessory Organs: Accessory Organs Nails - white base (lunula) is the most actively growing part (.1mm/day) Holocrine Glands: Holocrine Glands Sebaceous glands produce sebum which inhibits bacterial growth, may be antifungal Keeps hair and skin soft, pliable, and waterproof. Sweat Glands: Sweat Glands There are 2 kinds, eccrine and appocrine. Eccrine Glands: Eccrine Glands Not found with hair follicles, Lower body temperature Most are found on the forehead, back and neck, 3 million total. Average day you sweat out 1 quart Apocrine Glands: Apocrine Glands Found with hair follicles, active during emotional stress, sexual stimulation, found in the armpits and groin. Hormones cause them to develop Ceruminous Glands: Ceruminous Glands A specialized apocrine gland Produce wax (cerumen) in the ear Regulation of Body Temperature: Regulation of Body Temperature Homeostatic mechanisms help keep body temperature constant. Heat Related Illnesses: Heat Related Illnesses Heat Cramps Thirst, chills, clammy skin, nausea, muscle pain and spasm. Drink water, move to shade. Heat Related Illnesses: Heat Related Illnesses Heat Exhaustion Reduced sweating, dizziness, headache, fatigue Drink water, ice on head and neck, cool shower Heat Related Illnesses: Heat Related Illnesses Heat Stroke No sweat, high body temp., deafness, halucination Call 911, place ice on head and neck, put in cold shower Cold Related Illness: Cold Related Illness Hypothermia Lowering of body temperature Reduced metabolic and heart rates Impaired mental function Can end in deep coma or death Dehydration: Dehydration Effects Increase in sodium chloride in body fluid Decrease the volume of blood plasma Decrease cardiac output Decrease blood flow to skin Increase in core body temperature Dehydration: Dehydration Prevention/Treatment Eat a balanced diet and drink adequate fluids Drink 500mL of fluid about 2 hours before exercise During exercise drink cool non-carbonated beverages (600 - 1200mL/hour) Dehydration: Dehydration For exercise longer than 1 hour sports drinks are recommended to replace lost minerals For exercise shorter than 1 hour plain water is as good as sports drinks Drink 1 liter of water for every kilogram of mass lost after exercise Healing Wounds: Healing Wounds Inflamation Blood vessels become more permeable and leak fluid around the site of the injury Scabs form if blood vessels are broken Healing Wounds (cont.): Healing Wounds (cont.) Fibroblasts join the wound together Granulation tissue may form over large wounds. Burns: Burns 2 million people seek treatment for burns annually 100,000 hospitalized 12,000 die First Degree Burns: First Degree Burns Epidermis is intact Increased blood flow to area No special treatment, will heal in a few days with no scars Second Degree Burns: Second Degree Burns Superficial - blisters form, will heal in 2-3 weeks Deep (partial thickness) - less regeneration, more scarring, dermis is damaged. Third Degree Burns: Third Degree Burns Subcutaneous nerves damaged, may not feel pain Skin may appear black, white, or red. Large amounts of fluid is lost, infection is likely Fourth Degree Burns: Fourth Degree Burns When body parts are partially or completely burned away. Burn Size Estimates: Burn Size Estimates Head and neck 9% Trunk 36% Arm 9% Leg 18% Peroneum 1% Critical Areas: Critical Areas Head - most senses are here, breathing starts here. Hands - damage here can be very handicapping. Groin - urinary, reproductive, and digestive exits are here. Slide41: Very common ABCD Asymmetry Borders Color Diameter Skin Cancer Types of Skin Cancer: Types of Skin Cancer Basal Cell Carcinoma Spread uncommon, very curable if found early Squamous Cell Carcinoma Occurs parts exposed to the sun Types of Skin Cancer (cont.): Types of Skin Cancer (cont.) Malignant Melanoma Most common in southern hemisphere where the ozone layer is thin. Deadly if not caught early!! Skin Cancer Prevention: Skin Cancer Prevention Use SPF 15 minimum. Wear hats and shirts with sleeves. Wear sunglasses to protect eyes from UV. Avoid tanning beds.