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Chapter 5 The Integumentary System © 2012 Pearson Education, Inc. http://farm2.static.flickr.com/1231/534175495_73a6d12308.jpg Integumentary System The largest system of the body • Cutaneous membrane (SKIN) • Outer epidermis (epithelial tissues) • Inner dermis (connective tissues) • Contents: • Originate in the dermis extend thru the epidermis to skin surface • Hair, Nails, Multi-cellular exocrine glands • Cardio vascular- Blood vessels in the dermis • Nervous - Sensory receptors for pain, touch, and temperature • Hypodermis (Superficial Fascia or Subcutaneous Layer) NOT PART OF THE SKIN • Loose connective tissue, below the dermis • Location of hypodermic injections © 2012 Pearson Education, Inc. Integumentary System FUNCTIONS of Skin 1. Protection 2. 3. 4. 5. 6. • underlying tissues and organs from abrasions • WBC in dermis…immunity • Keratin…water proofing • Production of melanin- skin color--protects from UV Excretion of salts, water, and organic wastes (glands) using sweat and sebum…protects from bacterial infections • “Acid mantle”- pH of skin 4-6- reduces bacterial growth Maintenance of body temperature (insulation and evaporation) • Sweat…evaporates to cause cooling • Blood vessels…vasoconstriction/vasodilation • Arrector pili…goose bumps Synthesis of vitamin D3 Storage of lipids Detection of sensations: touch, pressure, pain, and temperature © 2012 Pearson Education, Inc. Epidermis Avascular (no blood vessels) stratified squamous epithelium • Nutrients and oxygen diffuse from capillaries in the dermis Cells of the Epidermis • Keratinocytes- most abundant (90%) • Contain large amounts of the protein keratin • Protects from heat, microbes, and chemicals; releases a waterproof sealant • Water barrier forms between the S. granulosum and the S. spinosum – crucial for retaining water and preventing dehydration. © 2012 Pearson Education, Inc. Bound firmly to one another with numerous desmosomes which accounts for the toughness of the epidermis. Epidermis © 2012 Pearson Education, Inc. • Thin Skin - Covers most of the body (0.08mm “sandwich bag”) • Has four layers of keratinocytes 1- Stratum basale 3- Stratum spinosum 4- Stratum granulosum 5- Stratum corneum • Thick Skin -Covers the palms of the hands and soles of the feet (0.5mm standard paper towel) • Has five layers of keratinocytes from basal lamina to surface 1. Stratum basale (S. Basale) 2. Stratum spinosum (S. Spinosum) 3. Stratum granulosum (S. Granulosum) 4. Stratum lucidum (S. Lucidum) 5. Stratum corneum (S. Corneum) © 2012 Pearson Education, Inc. Epidermis STRATUM BASALE – Deepest and thinnest layer- thought to be a single layer of cells • Attached to basement membrane by hemi-desmosomes • Produces a strong bond between epidermis and dermis • Forms epidermal ridges (fingerprints) • Dermal papillae (tiny mounds) • Strengthens attachment between epidermis and dermis • Area is actively dividing -has many basal cells or germinative cells • Primarily comprised of basal keratinocyte cells, considered to be the stem cells of the epidermis. Kerotinocytes in this layer do not produce keratin. As new cells develop they are pushed upwards. Eventually the cells will be little more than a plasma membrane and keratin. • Specialized Cells • Merkel (tactile) cells- nerve cells (1%)-most sensitive skin w/o hair- release chemicals that stimulate sensory nerve endings • sense of light touch; discrimination of shapes and textures. • Melanocytes (8%) • Contain the pigment melanin scattered throughout S.basale • Absorb damaging ultraviolet (UV) light © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Epidermis STRATUM SPINOSUM — consists of spiny prickle cells; interlock to support the skin • When processed cells shrink. Strength of desmosomes create pulling action resembling miniature “spiny” pincushions. Not seen in living cells. • Deeper layers continue to divide, increasing thickness of epithelium; upper layers no longer participate in mitosis • 99% of cells (8-10 layers bound by desmosomes) are kerotinocytes produced by division of stratum basale- are prekeratin. • Contain dendritic (Langerhans) cells (1%) derived from bone marrow = White Blood Cells (WBC) participate in immune response against pathogens that penetrate the skin • Phagocytize melanin from melanocytes present in S basale © 2012 Pearson Education, Inc. Epidermis Stratum Granulosum — the “grainy layer” • 3-5 keratinocytes layers • Cells stops dividing begin producing keratin, a tough, fibrous protein found in hair and nails • As keratin fibers develop the cells grow thinner and flatter. Membranes thicken and become impermeable • Cells produce keratohyalin granules that dehydrate the cell; nucleus and other organelles disintegrate and cell dies. This creates a tightly interlocked layer of cells. • Lamellated granules secrete glycolipids into the extracellular space, form around the fibers and produce a water barrier. © 2012 Pearson Education, Inc. Epidermis Stratum Lucidum — the “clear layer” • Found only in thick skin - palms, feet soles • protects against sun ultraviolet-ray damage Stratum corneum the “horn layer” • 15 to 30 layers of keratinized cells thick • Top layer flat, dead cells- Packed with keratin • Water resistant but not water proof; water from interstitial fluids penetrate the surface and evaporate-insensible perspiration • S. Corneum continuously sheds and is replaced every 2 wks • Dead cells call dander • Dandruff –clumps of dander stuck together with sebum (oil) • Keratinization - Formation of a layer of dead, cells filled with keratin; Occurs on all exposed skin surfaces except the eyes • Keratin protects the body from melanin and UV rays © 2012 Pearson Education, Inc. Cell Types and Layers of the of the Epidermis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sweat pore S. Corneum Exfoliating keratinocytes S. Lucidum Stratum granulosum Dead keratinocytes Sweat duct Living keratinocytes Dendritic cell Stratum spinosum Tactile cell Melanocyte Stem cell Stratum basale Dermal papilla Tactile nerve fiber Dermis Dermal blood vessels Figure 6.3 © 2012 Pearson Education, Inc. PERSPIRATION Epidermis • Insensible perspiration- UNAWARE • Interstitial fluid lost by evaporation through the stratum corneum (500 ml/d) • Cannot see or feel water loss • If cells of the S corneum are damaged their effectiveness as a water barrier is compromised. The superficial and deeper layers of the epidermis are separated. Fluid accumulates between producing blisters. • Dehydration results: • Severe damage to S. Corneum (serious burns) results in excessive loss of interstitial fluid and life-threatening circumstances • Sensible perspiration -AWARE • Water excreted by active sweat glands © 2012 Pearson Education, Inc. Skin Color Influenced by Pigments Carotene- Orange-yellow pigment (found in fruits/vegetables) • Can accumulate in epidermal cells and fatty tissues of the dermis • Can be converted to vitamin A • Gives yellow hue to the palms, feet, corns Hemoglobin • Network of blood capillaries varies in dermis • Gives reddish color to the skin © 2012 Pearson Education, Inc. Skin Color Melanin - Yellow-brown or black pigment • Approximately the same amount of melanin in ALL skin • Produced by melanocytes in stratum basale • Pigment phagocytized by keratinocytes of upper layers of epidermis • Synthesized from amino acid TYROSINE. The ENZYME TYROSINASE converts tyrosine into melanin. • Melanin protects skin from sun damage • Amount of pigment is controlled by: • Genetics – amount of tyrosinase • Melanin production, not number of melanocytes • UV exposure - stimulates melanin synthesis (ie: tan) • Causes DNA mutations and burns that lead to cancer and wrinkles © 2012 Pearson Education, Inc. Clinical Applications of Skin Color • Pallor: temporary reduction of blood flow to the skin due to shock, low BP, anemia • Cyanosis - bluish color in the nails and skin due to oxygen circulation deficiencies • Jaundice - yellowish color to skin and whites of eyes due to the buildup of yellow bilirubin in blood from liver/blood disease • Vitiligo: partial or complete loss of melanocytes patchy skin • Erythema: redness of skin due to dilation of blood capillaries in the dermis, caused by inflammation, infection, allergy or burns • Albinism: melanocytes are present but genetic condition fails to produce tyrosinase necessary to synthesize melanin no color in the skin, hair and eyes • Freckles: area of skin where melanin is increased and concentrated- no increase in melanocytes • Liver spots: INCREASE in melanocytes-unequal dispersal • Bruises: mass of clotted blood beneath the skin © 2012 Pearson Education, Inc. Cyanosis Jaundice Liver spots Vitiligo © 2012 Pearson Education, Inc. Albinism Skin Diseases • Athlete's foot (also known as ringworm of the foot) is a fungal infection of the skin that causes scaling, flaking, and itch of affected areas, and in severe cases, swelling and amputation of the foot • Oral herpes, colloquially called cold sores or fever blisters, is an infection of the face or mouth. Most common form of infection. © 2012 Pearson Education, Inc. Vitamin D3 • Epidermal cells produce cholecalciferol • In the presence of UV radiation • Liver converts cholecalciferol to calcidiol • Kidneys convert calcidiol into calcitriol • Aids absorption of calcium and phosphorus • Insufficient vitamin D3 • Can cause rickets in children • Causes osteomalacia in adults © 2012 Pearson Education, Inc. Skin Cancer 1 million cases diagnosed per year • three common forms of skin cancer 1. basal cell carcinoma (rarely metastasize) arises in epidermis 2. squamous cell carcinoma (may metastasize to lymph nodes) • Good recovery with early detection • Human papilloma virus associated with development 2. Squamous cell 1. Basal cell © 2012 Pearson Education, Inc. Skin Cancer malignant melanomas (metastasize rapidly) ≤ 5% of cancers arise from melanocytes most common cancer in young women Usually fatal-- 5-14% survival rate; causes the majority (75%) of deaths related to skin cancer • 6 months life expectancy following diagnosis • Melanoma cells preprogrammed with ability to metastasize. Unlike other cancer cells that must “learn” how to travel and spread to other regions of the body. • key to treatment is early detection watch for changes in mole asymmetry, border, color, diameter, evolving (“ABCDE”) • risks factors include-- skin color, sun exposure, family history, age and immunological status 3. • • • © 2012 Pearson Education, Inc. http://1.bp.blogspot.com/7TidcKtzFUk/UTOdRRFhP_I/AAAAAAAAAZs/Tzf4grG1ZU/s400/Malignant+melanoma.jpg http://sunsafekids.tripod.com/sitebuildercontent/sitebuilder © 2012 Pearson Education, Inc. pictures/melanomas.jpg THE DERMIS • Located between epidermis and subcutaneous layer • Connective tissue layer • collagen & elastic fibers; fibroblasts, macrophages & fat cells • Anchors epidermal accessory structures nerves, (hair follicles, nail roots, blood vessels, glands) Two major regions (zones) • papillary region • reticular region • Consists of dense irregular connective tissue • Contains larger blood vessels, lymphatic vessels, nerve fibers and collagen and elastic fibers © 2012 Pearson Education, Inc. Skin – Dermis PAPILLARY region • Lies directly beneath the epidermis and connects via finger-like projections - dermal papillae • Contains capillaries that nourish the epidermis • Upper region of dermis comprised of areolar (loose) CT • In hands and feet the papillae project into the epidermis and forms contours in the skin's surface called friction ridges that help to grasp by increasing friction. The ridges occur in patterns, fingerprints, that are genetically determined and are therefore unique to the individual • All of the ridges of fingerprints form patterns called loops, whorls or arches • Each ridge contains pores, which are attached to sweat glands under the skin which leave distinct patterns on surfaces. • Contains Meissner’s corpuscles (touch) & free nerve endings for sensations of heat, cold, pain, tickle, and itch; hands, feet, lips and genital organs; low nerve threshold (requires minimum stimulation to register sensation); sensitive to light touching. © 2012 Pearson Education, Inc. http://classes.midlandstech.edu/carterp/Courses/bio110/chap09/Slide2.JPG © 2012 Pearson Education, Inc. http://static.howstuf fworks.com/gif/fing erprint-2.gif © 2012 Pearson Education, Inc. Skin - Dermis RETICULAR region: • Dense irregular connective tissue • Lower region of dermis • Has glands, hair follicles and fat tissue • Specific arrangement of collagen fibers reflect on the surface as cleavage lines and wrinkle lines on the surface • Surgeons utilize these lines to improve healing time and decrease scaring; A parallel cut remains shut, heals well; a cut across (right angle) pulls open and scars • Provides strength and elasticity to the skin; Resist force in a specific direction © 2012 Pearson Education, Inc. Figure 5-8 Cleavage Lines of the Skin https://s3.amazonaws.com/classconn ection/944/flashcards/8985944/jpg/72 q-412-1525C77086D30FE02A5.jpg © 2012 Pearson Education, Inc. The Dermis- Clinical Applications • Dermatitis - inflammation of the papillary layer • Caused by infection, radiation, mechanical irritation, or chemicals (poison ivy) • Characterized by itch or pain • Skin Damage • Sagging and wrinkles (reduced skin elasticity) from • Dehydration; Age; Hormonal changes; UV exposure • Stretch marks • Thickened tissue resulting from excessive stretching of skin due to: pregnancy / weight gain • Psoriasis: more rapid division of the stratum basale thicker S corneum dry scales and flakes on the surface • Callus and Corns: frequent friction on skin over a bone (manual labor or tight shoes) increases keratinocytes replication resulting in thicker S corneum painful thickening • Skin treatments such as cortisone easily move through the epidermal layer of skin to reach the dermis. Cortisone is lipid based (steroid) and can easily move through the phospholipid bilayer plasma membrane of epidermal cells. © 2012 Pearson Education, Inc. Tattoos • A tattoo is a form of body modification, where a design is made by inserting ink, dyes and pigments, either indelible or temporary, into the dermis layer of the skin to change the pigment. • The presence of foreign material activates the immune system's phagocytes to engulf the pigment particles. As healing proceeds, the damaged epidermis flakes away as the connective tissue dermal layer mends and pigment is trapped within fibroblasts. • The word tattoo is a form of the Polynesian word meaning “to write”. © 2012 Pearson Education, Inc. The Dermis Dermal Strength and Elasticity • Presence of two types of fibers 1. Collagen fibers- very strong, resist stretching but bend easily- provide flexibility 2. Elastic fibers -permit stretching and recoil • Skin turgor- water content of the skin helps to maintain the properties of flexibility and resilience Innervation (Nerves) of the Skin • Nerve fibers in skin control: • Blood flow • Gland secretions • Sensory receptors • Light in dermal papillae • Deep pressure and vibration—in reticular layer © 2012 Pearson Education, Inc. The Hypodermis;Subcutaneous; Superficial fascia (NOT part of the Integumentary system! • Lies below the epidermis and dermis • Stabilizes the skin • Allows separate movement • Attaches skin to the underlying muscle layers • Made of elastic areolar and adipose tissues • Superficial area contains large arteries and veins; few capillaries and no vital organs • The site of subcutaneous injections using hypodermic needles. Drugs injected into this area of the skin due to high quantities of blood vessels and absorption capacity. • Subcutaneous fat distributions result of hormones (leptin, insulin) • Fat can be removed using liposuction which tears the adipose tissue from the body © 2012 Pearson Education, Inc. Accessory Structures: HAIR • Located in dermis • Project through the skin surface • 2.5 million hairs; 75% on general body surface and not the head • Body covered with hair, except: • Palms; Soles; Lips; Portions of external genitalia • Functions of Hair • Protects and insulates • Guards openings against particles and insects • Sensitivity to very touch • Types of Hair • Vellus Hair: Soft, fine; covers body surface • Terminal hairs: Heavy, pigmented • Head, eyebrows, eyelashes, and pubic area • Other parts of body after puberty © 2012 Pearson Education, Inc. Accessory Structures of Skin - Hair Hair comprised of Soft keratin and Hard keratin Hair parts: Shaft (visible) Root (imbedded) Layers of the Hair- medulla, cortex & cuticle Hair follicle = Jacket that surrounds hair root • Base of the follicle • Bulb • Surrounded by touch sensitive nerves – hair root plexus • Dermal papillae contains a knot of capillaries that supply nutrients for hair growth • Hair Matrix = Germinal cells in papilla for hair growth Arrector pili: • Smooth muscle band - attaches follicle to epidermis • Contracts goose bumps Sebaceous glands lubricate the hair / control bacterial growth © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Structure of Hair and Follicle three layers of the hair • medulla • flexible soft keratin- core of loosely arranged cells and air spaces • varies in thickness- Thick or coarse hair usually contains a medulla. • Fine hair for the most part lacks a medulla, as does naturally blonde hair. • cortex • constitutes the bulk of the hair; hard keratin- hard stiffness • cuticle • multiple layers of very thin, scaly cells that OVERLAP EACH OTHER- hard keratin- free edges directed upward. Accounts for split ends Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © 2012 Pearson Education, Inc. Hair Growth Cycle Growth stage = Active growth stage of the hair fiber • can last from 2- 7 years. At any given moment 80-85% of our hair is in this phase Resting stage = hair growth begins to “shut down” and stop activity • cells accumulate keratin & follicle atrophies • Old hair (club hair) falls out and growth stage begins again; new hair pushes the old hair out of the follicle • Normal hair loss is 70 to 100 hairs per day Growth and replacement Influences • Cycle affected by illness, diet, high fever, surgery, blood loss, severe emotional stress, and gender (hormones). • Chemotherapeutic agents affect the rapidly dividing matrix hair cells resulting in hair loss. © 2012 Pearson Education, Inc. Hair Color • Produced by melanocytes at the hair papilla • Determined by genes Hair color depends upon amount and type of melanin: • Dark hair – a lot of melanin • Red and blonde hair – different type of melanin • Gray hair – decrease in melanin production (decreasing tyrosinase) • White hair – absence of melanin and presence of air bubbles in hair medulla; without melanin hair is white as remaining hair structures are transparent. • Less melanin is produced as one ages © 2012 Pearson Education, Inc. Sebaceous Glands and Sweat Glands Exocrine Glands in Skin • • Sebaceous Glands (oil glands) • Holocrine glands; Secrete sebum Sudoriferous “Sweat” Glands - Watery secretion • Apocrine glands • Merocrine (eccrine) glands © 2012 Pearson Education, Inc. Glands of the Skin – SEBACEOUS GLAND (Oil) • Located in the dermis - 3-4 millions in adult skin • Absent in the palms and soles • Exocrine (holocrine) gland –cells are destroyed • produce sebum - contains cholesterol, proteins, fats & salts • Acinar glands accumulate lipids until engorged then burst • secretions are stimulated by hormones at puberty • Most sebum is secreted into hair follicles; exception: lips, eyelids • Function: • moistens hairs • waterproofs and softens /lubricates the skin • inhibits growth of bacteria & fungi (ringworm) Conditions: • Cradle cap in infants • Acne -- bacterial inflammation of glands © 2012 Pearson Education, Inc. sebacious apocrine Eccrine merocrine © 2012 Pearson Education, Inc. Glands of the Skin -SUDORIFEROUS GLANDS • Located in the dermis • Duct opens on to the surface of the skin • Two types: • heat induced (merocrine)-moves via ducts to surface of skin • emotional (apocrine) – open into hair follicle • Function: • regulates body temperature through evaporation (perspiration) • help eliminate wastes such as urea http://sweatthroughit.com/wp-content/uploads/2014/01/sweat-gland.jpg • Indicative of emotional or nervous responses Sweat: protein-free filtrate of blood plasma (water), salts, urea, lactic acid, ammonia…. • Released through exocytosis © 2012 Pearson Education, Inc. Merocrine (Eccrine) sweat glands 1. Located all over the body, more in the palm and soles 2. Secretory portion is in dermis with duct to surface Apocrine sweat glands (larger) Limited in distribution to the skin of the armpits, pubis, eyelids, ear canal, and nipples secretory portion in dermis ; duct opens into hair follicle 3. Active right after birth Active after puberty 4. Secretion is commonly referred to Secretions are more viscous, sticky and have a distinct odor. Source of pheromones. as “sweat” 5. regulate body temperature Do not play a role in thermoregulation of through evaporation (perspiration) the body – prevents overheating; help eliminate wastes such as urea, Responds to hormonal and nervous flushes microorganisms and stimulus other harmful chemicals © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Other Glands of the Skin Ceruminous (wax) glands: • Present in the skin lining the external canal of the ear • Modified apocrine sudoriferous gland • Secretes a waxy liquid (cerumen) • Function: Protection against moisture and insect entry into the ear canal Mammary (milk) glands: • Located between the pectoralis major muscle and the skin • Present in both male and female but only function in females-action of gland is triggered by pregnancy. • Modified apocrine sudoriferous gland • Secretes milk • Function: Nutrition for the newborn © 2012 Pearson Education, Inc. Sebaceous Glands and Sweat Glands Control of Glands • Sebaceous and Apocrine sweat glands • Autonomic nervous system (ANS) • Works simultaneously over entire body • Merocrine sweat glands • Controlled independently • Sweating occurs locally • Thermoregulation • Autonomic nervous system (ANS) • Works with cardiovascular system • Regulates body temperature • The main function of sensible perspiration © 2012 Pearson Education, Inc. Nails • Role: Protection - Made of thick, keratinized epidermis/hard keratin/ • Nail Plate is divided into: • Nail body - visible part • Nail root – embedded into the skin • Nail growth: in the nail matrix surrounding the nail root • Lunula: white region of the nail body…thickened stratum basale • Eponychium (cuticle): S. corneum layer that projects over nail body © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Nails and Health • Color • Discolored: diabetes • Bluish; asthma, heart condition, lung disorder • Pale nails; asthma • Yellowing: diabetes, liver issues • Black streaks: heart • White-reddish: folic acid, protein vitamin C Deficiency • Shapes • Curl under at tips: respiratory, heart • White and thin: Vitamin B12 deficiency • Vertical ridges: iron deficiency, poor nutrient/vitamin absorption • Horizontal ridges: mental stress in some cases normal • White spots: iron and zinc deficiency © 2012 Pearson Education, Inc. Repair of the Integument 1. Bleeding occurs due to dilated blood vessels • Mast cells trigger inflammatory response 2. A clot-scab (network of fibrin) forms restoring the integrity of the epidermis and restricting the entry of microorganisms • Germinative cells migrate around the wound • Macrophages remove the remaining clot and debris and deposit new collagen to replace it. • Granulation tissue forms – a combination of blood clot, fibroblasts, and blood vessels © 2012 Pearson Education, Inc. Tissue Injuries and Repair Inflammation – first response; redness, swelling, heat, pain • Triggered by trauma-injury, infection • Damaged cells release chemical signals into the surrounding interstitial fluid (Prostaglandins) • As cells break down: • Lysosomes release enzymes that destroy the injured cell and attack surrounding tissues • Tissue destruction is called necrosis • Dead tissue and cellular debris (pus) accumulate in the wound • Can form abscess – pus trapped in an enclosed area • Injury stimulates mast cells to release histamine, heparin, prostaglandins • Blood vessel dilate – bringing nutrients, O2, removing waste • Results in redness, pain, warmth, swelling © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Tissue Injuries and Repair • Regeneration • When the injury or infection is cleaned up • Healing (regeneration) begins • Process: • Fibroblasts/ Fibrocytes move into necrotic area • Lay down collagen fibers to bind the area together (scar tissue) • New cells migrate into area • Or are produced by mesenchymal stem cells • The four tissue types vary in their ability to regenerate and repair. • Epithelial and some connective tissue regenerate well • Nervous tissue and cardiac regeneration poor or not at all • Permanent replacement of normal tissue with scar tissue results in fibrosis (scar tissue formation); structure and function are not restored. © 2012 Pearson Education, Inc. Repair of the Integument 3. Epithelial cells multiply and spread beneath scab. • Epithelium regenerates while the underlying connective tissue undergoes fibrosis or scaring. • Fibroblasts produce the scar tissue. • Inflammation decreases, clot disintegrates 4. Scab sheds; Fibroblasts disappear • Epidermis and blood vessel are restored to normal function • A raised keloid (thick raised area of scar tissue) may form Wound Healing animation http://www.youtube.com/watch?v=IYL6vg89uds © 2012 Pearson Education, Inc. Keloid © 2012 Pearson Education, Inc. Burns Caused by: Fire, electricity, radiations, and chemicals Produces: Dehydration- most dangerous issue; lowered body temperature, decreased blood pressure, decreased or no urine production (kidneys shut down), infections • First degree burn – epidermis is damaged erythema, pain, flaking and peeling • Second degree burn – epidermis and part of the dermis is damaged erythema, blister formation, pain, partial loss of skin functions and some scarring • Blister –separation of the epidermis and dermis layers by a fluid-filled pocket. • Third degree burn – epidermis, dermis and accessories lost marble white area surrounded by redness, major scarring • Debridement: removal of dead skin (eschar) to prevent the spread of infection © 2012 Pearson Education, Inc. Degrees of Burn Injuries Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Full-thickness burns (a) First degree 1st degree © 2012 Pearson Education, Inc. (b) Second degree 2nd degree (c) Third degree 3rd degree Rule of Nines Head Trunk Arms Legs Groin 9% 36% 18% 36% 1% 100% Ex: burns that went into the dermis and occurred over entire surface of both arms would be classified as: • 2nd degree burn over 18% of the body © 2012 Pearson Education, Inc. Burn Therapy Skin Graft: • Autograft – skin from one area to another area of self • Isograft – skin from an identical twin…matching MHC antigens • Homograft – temporary graft skin from another person (donor, cadaver, foreskin) • Heterograft – temporary grafts from another animal (ie: pig, bovine) © 2012 Pearson Education, Inc. Effects of Aging on the Integumentary System • Cells • Epidermal thinning • Decreased numbers of dendritic (Langerhans) cells • Decreased melanocyte activity • Activity • Decreased glandular activity (sweat and oil glands) • Decreased function of hair follicles • Production • Reduced blood supply • Decreased vitamin D3 production • Reduction of elastic fibers • Decreased hormone levels • Slower repair rate © 2012 Pearson Education, Inc.