Hole s Human Anatomy and Physiology Eleventh Edition Shier Butler Lewis Chapter 6 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1
Referred to as Cutaneous Membrane Composed of several tissues including: Stratified squamous epithelium Glandular epithelium Dense irregular CT Smooth muscle Adipose Nervous tissue 2
1. Protection 2. Excretion 3. Regulates body temperature 4. Sensory reception 5. Contains immune system cells 6. Synthesizes Vitamin D 7. Acts as a blood reservoir 3
Physical Barrier From water loss From injury From chemicals and microorganism Chemical Barrier ph of 5-6 Prevents microorganism growth Biological Barrier Langerhan s cells (epidermis) Macrophages and mast cells (dermis) 4
Minimal amounts of urea and uric acid are excreted through the skin via sweat. 5
Uses negativefeedback mechanism. See Figure 6.11 on page 183 6
Hyperthermia abnormally high body temperature Hypothermia abnormally low body temperature 7
Light touch detection = Meissner s corpuscles Located in dermal papillae Concentrated in areas such as fingertips, palms, soles, eyelids, tip of tongue, genitalia Pressure detection = Pacinian corpuscles Located in deep dermis and subcutaneous regions 8
UV rays in sunlight activate Vitamin D synthesis Vitamin D needed for normal bone and tooth development 9
Dermis houses about 10% of the body s blood vessels Skin only requires 1-2% of the body s blood 10
Some cells (keratinocytes) produce substances that simulate development of some WBCs Langerhan s and macrophages Interact with T-helper cells 11
2 Layers Epidermis Dermis Subcutaneous layer beneath dermis NOT part of skin 12
AKA - hypodermis Composed of loose connective tissue adipose tissue Insulates Contains major blood vessels 13
http://www.youtube.com/watch?v=m7qirjxwhzc&feature=related http://vimeo.com/9143114 Epidermolysis Bullosa, or EB, is a rare genetic skin disorder the the majority of people have never heard of, yet it affects 100,000 children across the United States. Children born with this disease lack the ability to produce the collagen-7 protein that acts as a glue to bind the inner and out layers of skin together. 14
keratinized stratified squamous epithelium lacks blood vessels rests on basement membrane melanocytes provide melanin thickest on palms and soles (0.8-1.4mm) 15
1. stratum corneum outermost, composed of dead keratinized cells 2. stratum lucidum extra layer only found in thick skin of soles and palms 3. stratum granulosum 3-5 layers of flattened cells with keratin granules 4. stratum spinosum many layers of spiky cells with large nuclei 5. stratum basale innermost layer, single layer of mitosing cuboidal epithelium, containing melanocytes 16
on average 1-2 mm thick Functions: 1. binds epidermis to underlying tissues 2. Nourishment of epidermis Contains : Muscle cells Sensory receptors Blood vessels Hair follicles Glands 17
Papillary layer (20%) Composed of loose CT Papillae (finger-like projections) form fingerprints Meissner corpuscles 18
Reticular layer (80%) Composed of dense CT Bundles of collagen, elastic, and reticular fibers give skin its strength & resiliency Pacinian corpuscles 19
Hair Follicles Nails Sebaceous Glands (Oil) Sudoriferous Glands (Sweat) 20
epidermal cells tube-like depression extends into dermis hair root hair shaft hair papilla dead epidermal cells melanin arrector pili muscle 21
protective coverings nail plate nail bed lunula 22
usually associated with hair follicles holocrine glands secrete sebum absent on palms and soles 23
sudoriferous glands widespread in skin originates in deeper dermis or hypodermis eccrine glands apocrine glands ceruminous glands mammary glands 24
Genetic Factors varying amounts of melanin varying size of melanin granules albinos lack melanin Environmental Factors sunlight UV light from sunlamps X rays darkens melanin Physiological Factors dilation of dermal blood vessels constriction of dermal blood vessels accumulation of carotene jaundice 25
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Skin becomes scaly Age spots appear Epidermis thins Dermis becomes reduced Loss of fat Wrinkling Sagging Sebaceous glands secrete less oil Melanin production slows Hair thins Number of hair follicles decrease Nail growth becomes impaired Sensory receptors decline Body temperature unable to be controlled Diminished ability to activate Vitamin D 27
Acne Vulgaris most common skin disorder sebum and epithelial cells clog glands produces whiteheads and blackheads (comedones) anaerobic bacteria trigger inflammation (pimple) largely hormonally induced androgens stimulate sebum production treatments include antibiotics, topical creams, birth control pills 28
Athlete s Foot Fungual infection usually in the skin of the toes and soles Ringworm Fungal infection on the skin that creates a ring like pattern Both like moist environments and are spread by direct contact or contact with contaminated objects.
Birth mark (aka nevus ) Over 80% of babies have one 2 types: vascular & pigmented Vascular involves blood vessels in skin Pigmented results from abnormal amounts of pigments in skin Common types include café au lait spots, moles, port-wine stains, Mongolian spots, and hemangiomas Can but rarely cause severe disfigurement & tumor growth
Boil vs Carbuncle Boil in a bacterial infection of the skin, produced when bacteria enter a hair follicle. Carbuncles are bacterial infections that have spread to the subcutaneous tissues.
Eczema Non-contagious skin rash, often accompanied by itching, blistering, crusting, scaling, oozing and bleeding. Some types are an inherited condition Psoriasis Skin cells grow at an abnormally high rate. Results in red patches with silvery scales Immune system related and can be inherited
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1 st degree (superficial partial-thickness burn) Only epidermis is involved Edema (swelling), shedding of surface skin Area will appear red in color Heals without scaring
2 nd degree ( deep partial-thickness burn) Involves both epidermis and dermis Fluid escapes from dermal capillaries and collects in epidermal cells.thus blistering occurs May be red in color or waxy white Usually heals without scaring
3 rd degree (full-thickness burn) Destroys the epidermis, dermis, & accessory structures of the skin Area will look leathery, and be red, black or white in color Skin grafts are necessary for healing (autograft or homograft) Scaring will occur http://www.youtube.com/watch?v=exo _ApjKPaI&feature=player_embedded
Carcinomas arise from epithelia cells squamous or basal types Usually treated by surgical removal Most common type of skin cancer Melanomas arise from melanocytes Harder to treat On the rise in last 20 yrs b/c of tanning habits