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Skin (Integumentary system)

Skin (Integumentary system). Functions Protection Prevents water exchange Insulation, heat exchange Holds things in Cushions Excretion Immune Sense receptors Synthesis of vitamin D. Structure Two layers of tissue Epidermis-stratified squamous Become keratinized (tough)

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Skin (Integumentary system)

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  1. Skin (Integumentary system) • Functions • Protection • Prevents water exchange • Insulation, heat exchange • Holds things in • Cushions • Excretion • Immune • Sense receptors • Synthesis of vitamin D

  2. Structure • Two layers of tissue • Epidermis-stratified squamous • Become keratinized (tough) • Separation of layers causes blisters • Occurs from friction or burns • Dermis-dense connective tissue • Subcutaneous (hypodermis) • NOT part of skin • Mostly adipose tissue

  3. Epidermis-composed of 5 strata (layers)-Deep to superficial • Stratum germinativum (basale)-undergoes cell division, receives blood • Stratum spinosum-flatter and more keratin (water-proofing layer) • Stratum granulosum-flatter and more keratin • Stratum lucidum-only occur where there is no hair, extra thick, no blood, lots of keratin-soles and palms • Stratum corneum-thickest layer (20-30 cells), full of keratin, completely dead • New epidermis every 25-45 days

  4. Dermis-hide (leather products)-superficial to deep • Papillary • Dermal papillae-projections that form ridges on surface of skin • Capillary loops-nourishment • Meissner’s corpuscles-touch receptors • Leave films of sweat behind-fingerprints

  5. Reticular layer-deepest layer of skin • Sweat and oil glands • Pacinian corpuscles-pain receptors • Many phagocytes-stop bacteria • Collagen and elastic fibers (DCT) • When body temperature rises, capillaries become dilated, heat leaves skin, causes redness • Decubitus ulcers (bedsores) –weight of body puts pressure on skin, restricts blood, cells die, skin cracks and sores

  6. Skin color • Amount and kind of melanin (yellow, red, brown)-found in stratum germinativum • Lots of melanin-brown skin-exposure to sun • Amount of carotene (yellow-orange) • Stratum corneum • Eating orange foods

  7. Amount of oxygen in blood (red) • Less melanin will allow to see easier • Cyanosis-bluish skin, poor oxygen • Emotions • Redness-embarrassed, fever, hypertension • Pallor (paleness)-stress, fear, anemia, low BP

  8. Jaundice (yellow)- liver disorder • Bruises-blood clotting under surface of skin • Easily bruised-lack of Vitamin C • Hematomas-bruising

  9. Appendages • Cutaneous glands-exocrine (ducts) • Sweat glands-2.5 million per person • Eccrine glands-produce sweat (water salt vitamins, nitrogen, lactic acid) • Empty in pores • Regulate heat • Apocrine glands-axillary and pubic regions • Empty into hair follicles • Contains fats and proteins • Bacteria use fats and make smell • Precise function is unknown-pain, stress, foreplay

  10. Sebacous glands-oil, everywhere except palms and soles • Secrete sebum (oil)-keeps skin moist and prevents hair from being brittle • Contains chemicals killing bacteria • Highly active during puberty • If blocked-whitehead, blackhead, acne

  11. Hair and hair follicles • Found in epidermis • Functions-protection (eyebrows and nose hairs), warmth • Root-part of hair in follicles • Shaft-projection from follicle • Three layers-medulla, cortex, and cuticle • Wearing away of cuticle, causes split ends • Melanin is hair color • Hair follicle-part that forms hair • Arrector pili muscles-pulls hair upright when cold or frightened (goose bumps)

  12. Nails-hoof or claw of animal • Nail matrix-responsible for growth • Nails become keratinized and die

  13. Homeostatic Imbalance • Athlete’s foot-itch caused by fungus • Boils and carbuncles-infection of hair follicle • Cold sores-small fluid filled blisters that itch, can be caused by herpes virus • Contact Dermatitis-caused by poison ivy, etc. (chemicals) • Impetigo-pink water filled lesion that develop yellow crust (bacterial) • Psoriasis-red lesions could be hereditary

  14. Burns • Rules of 9-divides body to easily quantify burn • 1st degree-only epidermis is damaged (sunburn) • 2nd degree-epidermis and dermis, blisters form-most painful • 3rd degree-destroys entire skin, growth of skin is not possible, not painful (burns nerves), infection, circulatory problems, water loss

  15. Cancer • ABCD • Asymmetrical borders • Border irregularity • Colors • Diameter > 6mm • Basal Cell Carcinoma-least malignant, most common, affects stratum germinativum, shiny with white edges • Squamous Cell Carcinoma-scaly reddened lesions. Thought to be sun-induced • Malignant Melanoma-only 5% of skin cancers, spread rapidly, 50% chance of survival

  16. Developmental Aspects • Decreased subcutaneous-elderly are cold • Thinning of skin-more bruising • Loss of elasticity-wrinkles, sped up by sun • Hair balding-by age 50 1/3 of hair follicles are gone, also male pattern baldness (genetic) • Hair graying-caused by delayed action gene-decreases melanin production

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