Integumentary system

1. Integumentary system And its appendages!

2. Membranes • Thin, sheetlike structure • Lines and protects body surface, body cavities and organs • Some secrete lubricating fluids to decrease fluids.

3. Membranes • 2 major categories • Epithelial • Made of epithelial and underlying connective tissue • Connective • Exclusively connective

4. Epithelial Membranes • 3 types • Cutaneous • Serous • mucous

5. Cutaneous Membrane • Skin • Approximately 16% of body weight

6. Serous membrane • Only on surfaces within closed cavities • Thin layer of simple squamous epithelium • basement membrane – connective tissue that holds and supports the epithelial tissue

7. Types of serous membranes • Parietal portion – lines cavity • Visceral portion – lines organs • Thoracic cavity – Pleura • Parietal pleura • Visceral pleura • Abdominal cavity – Peritoneum • Parietal peritoneum • Visceral peritoneum

8. Serous membrane conditions • Serous membranes secrete a thin watery fluid to help with friction. • Pleurisy – condition characterized by inflammation of membrane that line the thoracic cavity and lungs • Peritonitis- inflammation of serous membrane in abdominal cavity

9. Mucous membranes • Line body surface openings (to exterior) • Respiratory, digestive, urinary and reproductive tracts • Secrete thick, slimy material (mucus) • Mucocutaneous junction – area that skin and mucous membranes meet. • Lack accessory organs (hair, glands) • Eyelids, nasal openings, vulva, anus • Sites of common infections/irratiations

10. The Skin • 1 square inch of skin contains • 500 sweat glands • 1000 nerve endings • Yards of tiny blood vessels • 100 sebaceous glands • 150 sensors for pressure • 75 sensors for heat, 10 for cold • Millions of cells

11. Structure of skin • Epidermis – outermost, stratified squamous • Dermis – mostly connective tissue • Subcutanous – hypodermis – loose connective tissue and fat (insulation, stored energy)

12. Epidermis • Stratum germinativum • Undergo mitosis and reproduce – skin can repair itself • As new layers form, old move upward and slough off. • Pigment layer – melanin, melanocytes • Stratum corneum – tough outer layer (keratin)

13. Variations in skin • Cyanosis – skin is bluish grey, lack of blood flow • Vitiligo – areas of loss of epidermal melanocytes • Albinism – partial or total lack of melanin • Pregnancy mask – blotchy pigmented areas of brown pigmentation • Freckle – flat macule, genetic in light skin people • Age spots – flat pigmented lesions • Blisters – when specialized junctions between cells are weakened or destroyed.

14. Dermis • Cells are scattered apart with fibers in between (collagen and elastic) • Dermal papillae – parallel row of peglike projections (fingerprinting) • Stores specialized nerves for pressure, pain, temperature

15. Variations in dermis • Striae – stretch marks • As we age – elastic fibers lessen, amount of fat stored in hypodermis lessens = wrinkles • Strawberry hemangioma – malformation of dermal blood vessels (birthmarks) • Port wine stain – permanent, pigmented vascular birthmark • Stork bite – dilation of dermal capillaries

16. Appendages - Hair • Lanugo – hair of newborn, soft, fine • Hairless – lips, palms of hands, soles of feet • Hair follicle – tube where hair grows from hair papilla in dermis • Hair shaft – visible hair • Living hair papilla = growth • Alopecia – hair loss • Male pattern baldness – inherited • Arrector pili muscle – goose bumps – attached to dermal papilla and hair follicle

17. Receptors • Pacinian corpuscle – deep in dermis, detects pressures • Meissner’s corpuscle – superficial in dermis, detects light touch

18. Nails • Produced by cells of epidermis • Epidermal cells fill with keratin and become hard • Cuticle – fold of skin at base of nail • Lunula – nail body nearest root, little moon • Nail bed – under nail, pink because vascular • Onycholysis – lossof nail due to trauma

19. Skin glands • Sweat (sudoriferous) glands • Eccrine – transparent watery liquid, sweat • Apocrine – larger and secrete thicker, milky secretion, odor due to contamination and decomposition of the secretion by skin bacteria. • Sebaceous – oil for hair and skin • Secretion – sebum • Increase during puberty – pimples • Acne = papules (inflamed lesions), pustules (pus filled pimples

20. Functions of skin • Protection • Temperature regulation • Sense organ activity