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Chapter 4 Skin and Body Membranes. Body Membranes Cover surfaces, line body cavities, form protective sheets 2 groups – classified according to tissue.

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Presentation on theme: "Chapter 4 Skin and Body Membranes. Body Membranes Cover surfaces, line body cavities, form protective sheets 2 groups – classified according to tissue."— Presentation transcript:

1 Chapter 4 Skin and Body Membranes

2 Body Membranes Cover surfaces, line body cavities, form protective sheets 2 groups – classified according to tissue

3 Epithelial membranes Aka covering and lining membranes Do contain some connective tissue Considered simple organs (1) Cutaneous membrane – Skin –Dry membrane

4 (2) Mucous membranes (mucosa) –Epithelium on top of lamina propria –Lines any cavity w/ an exterior opening –Wet (moist) membranes –Continuously covered by secretions –Ex. Respiratory, digestive, urinary, reproductive tracts –Adapted for absorption or secretion

5 (3) Serous membranes (serosa) –Simple squamous epithelium on areolar tissue –Line cavities closed to exterior –Occur in pairs Parietal layer – wall of ventral body cavity Visceral layer – covers organs in the cavity

6 –Serous fluid – btw layers – secreted by both layers –Allows organs to move w/out friction (heart,stomach) –Name depends on location Abdominal cavity – peritoneum; lungs – pleura; heart - pericardium

7 Connective membranes Aka synovial membranes Areolar tissue – no epithelial Line fibrous capsules around joints –Smooth surface –Secrete lubricating fluid

8 Line bursae (small sacs of connective tissue) and tendon sheaths Cushion organs that move against each other

9 Integumentary System Cutaneous membrane Aka integument – “covering” 2 layers – epidermis & dermis – usually very close –Burns/friction may cause separation = blister Functions –Insulates and cushions deeper organs –Regulates body temp – capillaries, sweat glands –Mini excretory system – urea, uric acid, salts, water released w/ sweat –Synthesizes immunity proteins –Synthesizes vitamin D –Contains cutaneous receptors – touch, pressure, temp, pain

10 Epidermis Avascular Keratinocytes – majority of cells – produce keratin (tough, protective, waterproofing) May have up to 5 strata (layers)

11 (1) Stratum basale –Deepest –Best nourished via diffusion –Aka stratum germinativum because they are continually dividing –Daughter cells are pushed upward –Contains melanocytes – produce melanin (pigment) –Sunlight stimulates production –Concentrated in 1 spot = freckles, moles

12 (2) Stratum spinosum (3) Stratum granulosum (4) Stratum lucidum –Dead – unable to get nutrients and oxygen –Occurs in hairless, extra thick areas – palms, soles of feet (5) Stratum corneum –20-30 cell layers (3/4 of epidermis) –Dead – completely filled w/ keratin –Aka cornified cells (corno = horn) –Rubbed/flakes off and is replaced by lower cells –Cycle days

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14 Dermis Hide – leathergoods Strong, stretchy envelope that holds body together 2 layers (1) Papillary layer –Upper dermal –Dermal papillae – projections on superior surface –Contain capillary loops which provide nutrients –May have Meissner’s corpuscles – touch receptors –Form ridges - fingerprints

15 (2) Reticular layer –Deepest skin layer –Contains blood vessels, sweat/oil glands, Pacinian corpuscles (pressure receptors) Both layers contain phagocytes that work to prevent bacteria from going deeper If blood supply is restricted = cell death = skin ulcers (bed sores) –Ex. Decubitus ulcers – found in bedridden patients

16 Collagen fibers – provide toughness –Attract/bind water – keep skin hydrated Elastic fibers – give skin elasticity –# of fibers decreases – allows wrinkles Blood vessels help maintain temp –To release heat – vessels swell –To conserve heat – vessels constrict, may bypass capillaries

17 Hypodermis Subcutaneous tissue – adipose tissue Not part of skin Acts as an anchor, shock absorber, insulator

18 Skin Color 3 pigments –Melanin – yellow, brown, black –Carotene – yellow-orange –Oxygen-rich hemoglobin – red/pink Emotional stimuli or disease affect color Redness (erythema) –Blushing, fever, inflammation, allergy

19 Pallor (blanching) – become pale –Anemia, low blood pressure, fear Jaundice (yellow cast) –Liver disorder – bile deposited in tissues

20 Bruises (hematomas) –Where blood has left vessels and clotted in tissue space –May be vitamin C deficit or hemophilia

21 Cyanosis –Bluish cast due to low oxygen –Common in people with breathing disorders


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