Integumentary System

Classes of Body Membranes Epithelial  Cutaneous-Skin –Keratinizing, stratified, squamous epithelium superficial to fibrous connective tissue –Dry

 Mucous- –Epithelial tissue on top of a loose connective tissue base –Lines all body cavities open to the outside –Wet

 Serous –Simple squamous epithelium attached to areolar connective tissue –Lines body cavities closed to the outside –Parietal vs. Visceral layers –Serous fluid between layers

Connective Tissue Membranes  Synovial –Composed only of connective tissue –Lines the fibrous capsules surrounding joints where they provide smooth surface and secrete lubricating fluid –Also lines small sacs of connective tissue called bursae and the tube-like sheaths of tendons –Cushions organs moving against eachother during muscle activity (i.e. tendon across a bone’s surface)

Skin Functions  Barrier to keep insides in and outsides out  Protection from bacterial invasion, chemical exposure, UV, mechanical damage  Thermal homeostasis  Production of Vit. D  Houses sensory receptors

SKIN  Epidermis: –Outermost layer of skin –Made up of stratified squamous epithelium –Keratinization…outermost cells are dead

 Dermis: –Deep to the epidermis –Made up of dense connective tissue –Dermis and epidermis are firmly connected, though a burn or friction may cause them to separate, forming a blister

 Subcutaneous Tissue-Hypodermis –Deep to the dermis –Made of adipose tissue (fat) –Anchors skin to underlying tissues –Insulator and shock absorber

Burns  Life Threatening Concerns: –Dehydration (loss of fluid from damaged areas)  Dehydration can lead to the shut down of kidneys and circulation shock (low blood volume) –Infection  Burned area is only sterile for about 24 hrs. After that bacteria can invade.

Burns By Degree  1 st Degree –Only epidermis is damaged –Red and swollen like a sunburn  2 nd Degree –Epidermis and upper region of dermis –Red and painful w/blisters and/or seepage  3 rd Degree –Entire thickness of skin damaged –Grey-white or blackened –Classified as critical if:  Over 25% of body with 2 nd degree burns  Over 10% of body with 3 rd degree burns  3 rd degree burns of face, hand and feet

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Rule of Nines: Estimation of Fluid Loss Due to Burns  Anterior Surfaces –Trunk 18% –Legs 9% each –Arms 4.5% each –Perineum 1%  Posterior Surfaces –Trunk 18% –Legs 9% each –Arms 4.5% each –Head and Neck 4.5%