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Chapter Four. Skin and Body Membranes. Classification of Membranes. Epithelial Cutaneous Skin Stratified squamous Mucous (mucosa) Lines cavities Simple columnar Serous One layer Simple squamous Serous fluid Parietal & Visceral Lines body cavities Around organs
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Chapter Four Skin and Body Membranes
Classification of Membranes • Epithelial • Cutaneous • Skin • Stratified squamous • Mucous (mucosa) • Lines cavities • Simple columnar • Serous • One layer • Simple squamous • Serous fluid • Parietal & Visceral • Lines body cavities • Around organs • Pleura & Pericardium • Simple squamous
Functions of the Skin • Protection • Against disease • Insulates & cushions • UV protection • Chemical protection • Defense • 1st line of defense • Prevention of Dehydration • Keratin • Keeps H2O in & out
Functions of the Skin • Maintenance of Body Temp. • Heat loss – sweat • Heat retention – blood flow • Excretion of Wastes • Salts • Urea • H2O • Reception of Stimuli • Touch, pressure, pain, cold, heat • Vitamin D Synthesis • Cholesterol molecules Vitamin D (sunlight)
Layers of the Skin - integumentary • Epidermis • Strata • Stratum basale • Closest to dermis • Undergoes mitosis • Nutrients from diffusion • Stratum spinosum • Flattened cells w/ spines • Stratum granulosum • Granules w/ keratin • Stratum corneum • “horny” • 20-30 cell layers • Soles. Palms, fingertips-stratum lucidum
Cell Types • Keratinocytes • Make keratin • Melanocytes • Make melanin • Secretes melanin – basale layer • Langerhans cell • Macrophages-eat foreign substances
Skin Color – amount and kind • Pigments • Melanin • Reddish brown, or black • Carotenes • yellow • Hemoglobin • rosy • Emotional • Redness (sympathetic) • Embarrassment • Anger • Fear • Allergies
Dermis – “hide” leather • Thick connective tissue layer beneath stratum basale. • Collagen • Elastin • Papillary layer • Upper, uneven • Receptors (pain, touch) • Dermal papillae • Fingers-fingerprints • Soles-footprints
Dermis cont… • Reticular layer • Deepest • Blood vessels • Sweat and oil glands • Blood supply when restricted • Degeneration • Ulceration – bed sore
Appendages of the Skin • Glands • Sebaceous glands • Oil • Sebum: lubricant, bacteria killing • Whiteheads (blocked oil gland) blackhead acne • Seborrhea – excess oil • Sweat glands – 500 ml a day (25 million) • Eccrine • Sweat • Clear • 99% water • Salts, urea, lactic acid, • pH 4-6 • Apocrine • Axillary & genital areas • Fatty acids, proteins, sweat (yellowish) • Empty into hair follicles
Appendages of the Skin cont.. • Nails • Modified epidermal cells • Keratin • Hair • 100,000 hairs scalp • Follicle • Keratinized cells • Arrector Pili (goose bumps)– smooth muscles -Hairs erect-increase blood flow to skin • Cuticle • Keep hairs separate
Infections and Allergies1000 different conditions • Fungi • Athletes foot fungus • Ringworm • Bacterial • Boils and carbuncles • Staphylococcus into hair follicles • Oil glands • Impetigo • Viruses • Herpes “cold sores” • Warts
Allergies • Eczema • Contact dermatitis • “rash” • Unknown • Eczema • Psoriasis • Hives • Yeasts
Skin in Stress • Wound Repair • Wound • Inflammatory reaction • Blood flow • Edema • swelling • Clots • Stop bleeding • WBC’s • Fight bacteria • Pus • Dead blood cells • Dead bacteria • Scabs
Skin in Stress cont… • Burns • Thermal • Heat • Chemical – electrical - UV • First degree • Epidermis “red” • Heal 2-3 days • Second degree • Epidermis & dermis • Blisters • Third degree • Skin blackens • Skin grafts • Risk of death • Fluid loss , imbalance of electrolytes • Kidney failure • Replace proteins , infection
Skin Cancer • Basal Cell Carcinoma • Most common • Alters stratum basale cells • Uncontrolled mitosis can’t form keratin • SquamousCell Carcinoma • Stratum spinosum • Scaly reddish papulae • Spreads to lymph nodes • Malignant Melanoma – (5%) • Brown black patches • Lymph & blood vessels • ABCD rule moles • Asymmetrical, border, color, diameter 76mm
Disease States • Erythema • Turns red • Pallor, blanching • Anemia • Low blood pressure • Jaundice • Yellowing • Liver disorder • Porphyria • purple • Bruises • Hematoma • Broken capillaries • Cyanosis • “bluish” • Low 02 in blood