1. Chapter 4 Skin and Body Membranes

2. Body Membranes Body Membranes: Covers surfaces, lines body cavities and forms protective (lubricating) sheets around organs.

3. I. Classification of Body Membranes A. Epithelial Membranes: simple organs made of an epithelial sheet combined with a layer of connective tissue. 1.Cutaneous Membrane: Integumentary System (Skin) * Exposed to air/dry membrane 2.Mucous Membrane (mucosa) * Lines body cavities that are open to the exterior (ex: respiratory, digestive, urinary, reproductive tracts)

4. Epithelial Membranes, cont’d 3. Serous Membrane (serosa) * Occurs in pairs: - Parietal Layer lines body cavity - Visceral Layer covers the organs * Ex: Peritoneum – lines abdominal cavity, Pleura – surrounds lungs, Pericardium – surrounds heart

5. A.Connective Tissue Membrane A.Ex. Synovial membrane B.Lines fibrous capsules surround joints. *Membranes make FLUIDS and MUCUS!

6. Cutaneous membrane, sweat & oil glands, hair and nails A.Basic Skin Functions ~ Protection, insulations, excretion, synthesis of vitamin D ~ Cutaneous sensory receptors – touch pressure, temperature, and pain receptors II. Integumentary System

7. B. Structures of the Skin ~ Tissue of the Skin * Epidermis – outer layer/stratified squamous epithelium capable of keratinizing (hard and tough) ~ Burn or friction may cause epidermis and dermis to separate (blister)

8. Structures of the Skin, cont’d ~ Subcutaneous tissue/hypodermis – adipose * anchors skin to underlying organs * function: shock absorber, insulates, and forms curves

9. 1. Epidermis Avascular Kerantinocytes (keratin – fibrous protein)

10. 1. Epidermis, cont’d… 5 Layers – Stratum basale (geminitivum) – Stratum spinosum – Stratum granulosum – Stratum lucidum – Stratum corneum

11. 1. Epidermis, cont’d… Melanocytes (melanin) – Sunlight stimulates melanin production (tan) – Freckles & Moles – accumulation of melanin

12. 2. Dermis – “hide” - Leather 2 Layers Papillary layer – fingerprints, Meissner’s corpuscles – touch & pain. Reticular layer – blood vessels & glands; collagen & elastic fibers; Pacinian corpuscles – deep pressure

13. 2. Dermis, cont’d… Fever – Dermal capillaries swell Skin red & warm Heat radiates from skin

14. 2. Dermis, cont’d… Decubitus Ulcers (bed sores) Poor circulation Dead skin cells

15. C. Skin Color Pigment (melanin & carotene)

16. C. Skin Color, cont’d… Dermal blood vessels (oxygenated blood) Cyanosis – poorly oxygenated blood (blue) Erthema - blushing Pallor or blanching - pale Jaundice – Yellow; liver disorder Bruises – black or blue (hematoma – blood mass)

17. D. Appendages of skin Sebaceous glands (oil) Sebum – lubricant Kills bacteria Active – adolescent (hormones) Acne – infection of oil gland

18. D. Appendages of skin, cont’d… Sweat glands Eccrine sweat glands Sweat Antibacterial Body heat regulation

19. D. Appendages of skin, Sweat glands, cont’d… Apocrine sweat glands Axillary – milky, yellowish, odorless Bacteria causes body odor Activated - puberty

20. D. Appendages of skin, cont’d… Hair Hair follicle/hair root/hair shaft/cuticle (split ends) Hormones stimulate hair growth Hair color - melanin

21. D. Appendages of skin, cont’d… Nails Keratinized dead cells Nail bed – pink/rich blood supply Lunula – white crescent at base of nail