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Chapter Four Skin and Body Membranes. Classification of Membranes Epithelial – Cutaneous Skin Stratified squamous – Mucous (mucosa) Lines cavities Simple.

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Presentation on theme: "Chapter Four Skin and Body Membranes. Classification of Membranes Epithelial – Cutaneous Skin Stratified squamous – Mucous (mucosa) Lines cavities Simple."— Presentation transcript:

1 Chapter Four Skin and Body Membranes

2 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

3 Functions of the Skin Protection – Against disease – Insulates & cushions – UV protection – Chemical protection Defense – 1 st line of defense Prevention of Dehydration – Keratin – Keeps H 2 O in & out

4 Functions of the Skin Maintenance of Body Temp. – Heat loss – sweat – Heat retention – blood flow Excretion of Wastes – Salts – Urea – H 2 O Reception of Stimuli – Touch, pressure, pain, cold, heat Vitamin D Synthesis – Cholesterol molecules  Vitamin D (sunlight)

5 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

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8 Cell Types Keratinocytes – Make keratin Melanocytes – Make melanin – Secretes melanin – basale layer Langerhans cell – Macrophages-eat foreign substances

9 Skin Color – amount and kind Pigments – Melanin Reddish brown, or black – Carotenes yellow – Hemoglobin rosy Emotional – Redness (sympathetic) Embarrassment Anger Fear Allergies

10 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

11 Dermis cont… Reticular layer – Deepest – Blood vessels – Sweat and oil glands – Blood supply when restricted Degeneration Ulceration – bed sore

12 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

13 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

14 Infections and Allergies 1000 different conditions Fungi – Athletes foot fungus – Ringworm Bacterial – Boils and carbuncles Staphylococcus into hair follicles Oil glands – Impetigo Viruses – Herpes “cold sores” – Warts

15 Allergies – Eczema – Contact dermatitis – “rash” Unknown – Eczema – Psoriasis – Hives Yeasts

16 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

17 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

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19 Skin Cancer Basal Cell Carcinoma – Most common – Alters stratum basale cells Uncontrolled mitosis can’t form keratin Squamous Cell 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

20 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


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