integumentary system skin & its appendages (hair, nails, skin glands) integument = skin, principle...

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  • Integumentary System

    Skin & its appendages (hair, nails, skin glands)

    Integument = skin, principle organ of integumentary system

  • Functions of Skin (cutaneous membrane)

    Protection

    1st line of defense vs microbes. Tough cells of stratum corneum (thick skin b/c stratified squamous epis) protects vs. tears, cuts Keratin (protein) H2O proof protects vs fluid loss, keeps fluids in Melanin in pigment layer prevents UV rays from penetrating body

    Vit D manufactured in skin w/ sunlight (uvB Rays)helps Ca/P absorption strong bones

  • Temp Regulation

    Regulates sweat secretions sweat evaporates heat lost

    Regulates flow of blood close to body surface Blood vessels dilate close to surface heat lost by radiation

    Blood vessels constrict heat conserved

  • Sense Organ

    Millions of nerve endings, receivers for body, keep it informed of environmental changes, react to stimuli (pain, pressure, temp, etc)

  • Structure of the skin Skin is cutaneous membrane: sheetlike organ composed of 2 layers of distinct tissue

    Epidermis: Outermost skin layer Thin sheet of stratified squamous epis

    Dermis: Deeper layer Thicker than epidermis Consists of mostly connective tissue

  • Subcutaneous TissueLoose connective tissue & fat Not part of skin itselfCarries major blood vessels & nerves to skin above Rapid, painfree absorption of injected materialSpongy, porous layer

  • Stratum Basale

  • EpidermisStratum corneum Dead, flat cells full of keratinKeratin is waterproof proteinCells are shed/sloughed

    Stratum lucidum (lucid = clear apparent in thick skin3-5 layers of clear cellsThicker areasSoles of feet, palms prints

  • Stratum granulosum3-5 layers Keratinization begins hereCytoplasm replaced w/ tough, H2O proof proteinCells beginning to die

  • Stratum spinosum 8-10 layers Keratinocytes take in keratin

  • Stratum basale (stratum germinativum)Single layer of cuboidal to columnar cellsStem cells that produce keratinocytesMelanocytes - # the same for all racesMelanin produced in a melanosomeBasal cell to surface about 2-4 weeks

  • Increased [melanocyte] deeper skin color

    Sun melanocytes w/ melanin tan

    sun exposure melanin deposits in dermis

    [melanin] in relation to blood vol or [O2]

    blood flow to skin pink, flush, blush

    blood flow to skin bluish gray - cyanosis

    *Notice above more w/ less w/ [melanin]

  • When skin cells deprived of O2 Decubitus UlcerBed SoresTissue breaks down Decubitus Ulcer of Elbow

  • Cells of epidermis pkd tightly & held together by spot welds

    (junctions btwn membranes of adjacent cells. If weakened/destroyed skin falls apart) Burns, friction, irritant exposure blisters (top layer raised fluid filled)

  • Fx in immune response, damaged by UV radiationContains melanin skin color, absorbs UV radiation90% of epidermisMerkel cells in deep in epidermis hairless areas ? Fx in touch sensation

  • *Merkel cell in deepest layer of hairless skin ? Fx in touch sensation*

  • Dermal-Epidermal Junction: junction between thin epidermal layer of skin above and thicker dermal layer below

    2. Dermis: Deeper of 2 primary layers Much thicker, Made mostly of connective tissue Cells scattered w/ fibers in between, not pkd like Epidermis

    Fibers: some tough & strong others stretchable, elastic

  • Upper Dermis: Dermal Papillae // rows of peglike projections

    Important part of dermal-epidermal junction helps bind 2 skin layers together

    Forms ridges & grooves fingerprinting/ID Epidermis follows contours of dermal papillae Develop before birth, unique, individual, never changes but to grow larger fingerprints & footprints (+ ID)

  • Deeper area of dermis filled w/ dense network of interlacing fibers collagenous giving toughness to skin

    Elastic fibers also present stretchable, elasticity Age, # of elastic fibers in dermis, amt fat stored in subcutaneous tissue wrinklesloss of elasticity, sags, pliant

    (botox, collagen injections, retinol, collagenous fibers wrinkles!

  • Appendages of the skin

    Hair: human body covered w/ hair

    At birth, most follicles required for hair growth present

    Lanugo: newborn hair, fine & soft, lost & replaced w/ new, stronger & more pigmented hair

  • Lips, palms, soles hairless

    Most body hair invisible

    Most visible on scalp, eyelids, eyebrows

    Pubic & Axillary (under arm) hairs develops w/ puberty (result of hormone secretions)

  • Cells of epidermis grow into Dermis forming hair follicle (sm tube)

    Hair growth begins from cluster of cellsHair Papilla located at follicle base

    **

  • Papillanourished by a dermal blood vesselRoot hidden in follicleShaft (dead cells)visible part of hair

    As long as cells in Papilla alive, newHair replaces pluckedNeither makes hair Grow faster of effects epithelial cellsThat form hairs b/c theyre embedded in dermis

    Depilliatories destroy protein in hair shaft (Ex. Nair)****

  • Arrector Pili(Errects hair)Smooth/involuntarymusclesAttached at base of dermal papillaabove & to side of follicle Frightened or cold contract

    Each muscle pulls on 2 points of attachmentup on hair follicle,down on part of skin goose bumps *

  • Sensory Receptors: allows body surface to act as sense organ Relays messages to brain, sensations of pain, temp, pressure Meissners Corpuscle: dermis surface, light touch Pacinian Corpuscle: deep dermis, detects pressure

    Thermoreceptors: temp receptors in skin (detect stimulus & send impulse to hypothalamus (control center) in brain (Uses feedback loop, like thermostat)

  • Nails: accessory organs of skin, produced by cells in epidermis. Epidermal cells over terminal ends of fingers/toes fill w/ keratin (protein) hard, plate like

  • Nail Plate/Body: visible part of nail Root: lies in groove, hidden by fold (cuticle)Luna: (little moon) crescent shaped white area near rootNail Bed: under nail, thin layer of epithelium has blood vessels pink & translucent blood (O2) cyanosis blue nail bed free edge

  • Skin Glands

    Sweat / Sudoriferous Glands: most numerous

    eccrine sweat glands (most) sm. distributed all over body surface produce perspiration/sweat eliminates wastes (NH3, UA, maintains BT) 1 sq inch = 3000 eccrine glands pores (outlets of small ducts)

    apocrine sweat glands 10 in armpit & pigmented skin @ genitals. (scent glands)Lgr vs eccrine & secrete thicker, milky secretions, odor from contamination & decomposition of secretion by skin bacteria. Enlarge / function @ puberty

  • Most numerousArmpits, pigmented areas, genital areasOil glands, secrete sebum, s after puberty (opens to hair follicles)

  • Sebum during adolescence, stimulated by blood levels of sex hormones

    Sebum accumulates, enlarges duct of sebaceous gland white pimples darkens blackhead

    Acne Adolescence overactive secretion of sebaceous glands w/ blockage & inflammation of ducts Ages 10-195x sebum secretion sebaceous gland ducts get plugged w/ skin cells & sebum w/ bacteria comedo (pus filled pimples from 20 infection w/in or beneath epidermis in hair follicle or sweat pore

  • Sebaceous Glands: Secrete oil (sebum) for hair & skin, Found wherever hair grows Tiny ducts open to hair follicles

    Secretion: Sebum, lubricates hair/skin

  • Milia: sm white bumps on newborn, accumulation of sebaceous gland material Vernix Caeseosa: oily substance produced by fetuss sebaceous glands

  • Burns fire, heat, UV light, chemicals, electrical

    Burns, treatment & recovery depend on: Total area involved Severity of burn determined by depth of injury & amt of body surface affected

    *Treatment Prevent fluid loss & infection Skin Grafts cultured

    Estimating Body Surface: (% body surface burned)

    Rule of 9s to determine extent of burn injury

  • Body divided into 11 areas of 9% each + 1% genitals Total = 100%Head front 4.5% back 4.5%

    Arms front 4.5% (x2) 9.0 back 4.5% (x2) 9.0

    Torso front 18% back 18%

    Legs front 9% (x2) 18.0 back 9% (x2) 18.0

    genitals 1%

  • Burn Classification:

    Based on # of tissue layers involved

    1st degree: Sunburn, minor discomfort, skin red surface layers of epidermis may peel 1-3d No blistering Minimal tissue destruction

  • 2nd degree: Involves deep epidermal layers Always causes injury to upper layer of dermis Damage sweat glands, hair follicles, sebaceous glands, BUT NOT complete dermis destruction Blisters, severe pain, swelling, fluid loss, scarring common

  • 3rd degree: Complete destruction of epidermis/dermis, tissue death extends below 10 skin layers into subcutaneous tissue, muscle & bone. Insensitive to pain (destruction of nerve endings) serious scarring

  • Types of Body Membranes

    Membrane: Thin, sheet-like structure

    Cover & protect body surfaceLine body cavitiesCover inner surfaces of organs (dig, reprod, resp) Anchor organs to each other or bonesCover internal organsSome membranes secrete lubricating fluids to friction during organ movements (Ex. heart beating, lung expansion/contraction, in joints between bone)

  • 2 Main Types of Body Membranes Epithelial Membranes Connective Membranes

    Cutaneous membranes Synovial membranesSkin (Integumentary)

    Serous membranes

    Mucous membranes

  • Epithelial Membranes

    a. Cutaneous membranes: (Epidermis/Dermis) skin

    10 organ of integumentary system

    skin outer epidermis composed of stratified squamous epithelial cells

    underlying epidermis is dermis made of connective tissue

    subcutaneous

  • Epithelial Membranes contdb. serous membranes: 2 distinct tissue layers

    (secrete thin watery fluid helps friction lubricant)

    1. epithelial sheet: thin layer simple squamous epis

    2. connective tissue layer: basement membrane supports epis

    2 Types of serous membranes Parietal lines walls of body cavities Visceral covers surface of organs in cavities

  • Pleura: Serous membrane of thoracic cavity

    Peritoneum: Serous membrane of abdominal cavity

    (lines cavities) (covers organs)parietal & visceral pleura (of thoracic cavity)parietal & visceral peritoneum (of abdominal cavity)

  • pleurisy: inflammation of serous membranes (pleura) lining chest cavity (parietal) and covering lungs (visceral)

    pain friction of lungs rubbing vs. walls of chest cavity

    peritonitis: inflammation of serous membranes lining abdominal cavity (parietal) and covering abdominal organs (visceral) Sometimes from infected appendix

  • Epithelial Membranes contdc. Mucous Membranes: Line body surfaces open to outside Structure depends on location Most secrete mucus moist, lubricate, protect keeps soft

    Respiratory: Ciliated simple columnar epis mucus Digestive: Esophagus: stratified epis resist abrasion Intestines: simple columnar epis Urinary/Excretory: simple cuboidal absorption Reproductory

  • Connective Tissue Membranes No Epithelial componentSynovial Membranes: Line joint spaces between bone Smooth, slick Secrete synovial fluid Line bursae sacs (cushion) between moving parts friction between joints

  • Now, Brain Storm and think of as many examples of how structure dictates function as you can,then explain them!