Tissues Epithelial Tissues Connective Tissues Muscle Tissues Nervous Tissues

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  • TissuesEpithelial TissuesConnective TissuesMuscle TissuesNervous Tissues

  • ObjectivesUpon completion of this chapter, you should be able to:Describe the general characteristics and functions of epithelial tissue.Name the types of epithelium and identify an organ in which each is found.Explain how glands are classified.Describe the general characteristics of connective tissue.Describe the major cell types and fibers of connective tissue.

  • ObjectivesUpon completion of this chapter, you should be able to:List the types of connective tissue that occur within the body.Describe the major functions of each type of connective tissue.Distinguish among the three types of muscle tissue.Describe the general characteristics and functions of nervous tissue.Complete the review activities at the end of the chapter.

  • Aids to Understanding Termsadip- fatchondr-cartilage-cytcellepi-upon-gliaglue (bind cells together)osseo-bonephago-to eatpseudo-falsesquam-scalestrat-layerstria-groove (alternating)

  • Epithelial TissuesCovering and lining; glandularAlways has a free surface, while underside is anchored to connective tissue by a thin, nonliving layer called the basement membrane (lamina)Lack blood vessels (nourished by substances diffusing from connective tissue)Reproduce readily.Protective barriers (skin, lining of mouth), secretion, absorption, excretion, and sensory reception

  • Epithelial TissuesClassificationArrangementSimple ~ single layers of cellsStratified ~ many layers of cellsPseudostratified ~ one layer w/ cells of differing heightsShapeSquamous ~ thin, flattened cellsCuboidal ~ cubelike cellsColumnar ~ elongated cellsTransitional ~ expandable

  • Simple Squamous EpitheliumSingle layer of thin, flattened cellsOccurs commonly where diffusion, osmosis, and filtration are taking placeair sacs of lungswalls of capillariesinsides of blood and lymph vesselscovers membranes that line body cavities

  • Simple Cuboidal EpitheliumSingle layer of cube-shaped cells w/ centrally located nucleusSecretion, AbsorptionKidney tubules Glands -- secretion of glandular productssalivary glandspancreasliverovaries

  • Simple Columnar EpitheliumSingle layer of elongated cells w/ nuclei located near basement membraneProtection, secretion, absorptionLining of uterusLining of various organs of digestive tract, e.g., stomach and intestinesMicrovilli often cover surface, increasing surface area for more effective absorptionGoblet cells scattered throughout, secreting protective fluid (mucus) onto free surface

  • Pseudostratified Columnar EpitheliumNuclei located at two or more levels within cellsCilia extend from free surfaceGoblet cells scattered throughout tissueProtection, secretion, movement of mucus and cellsLines passages of respiratory systemLines tubes of reproductive system

  • Stratified Squamous EpitheliumMany layers of cells; thickFlattened near surface, cuboidal or columnar deeperProtectionSkin (epidermis)As older cells are pushed outward, they accumulate the protein keratin, harden, and dieLines mouth cavity, throatLines vagina, anal canal

  • Transitional EpitheliumAlso called uroepitheliumSpecialized to undergo changes w/ tensionContracted, several layers of cuboidal cells; distended, appears to contain only a few layers of cellsDistensibility, protection, barrier from diffusioninner lining of urinary bladder passageways of urinary system

  • Glandular EpitheliumSpecialized to produce and secrete various substances into ducts or into body fluidsFound within columnar or cuboidal epitheliumExocrine glandsglands that secrete products into ducts that open onto some internal or external surfaceEndocrine glandsglands that secrete products into tissue fluid or blood

  • Types of Exocrine GlandsUnicellular glandsSingle secretory cellmucus-secreting goblet cell

    Multicellular glandsSimple glandscommunicate with surface by means of unbranched ductsCompound glandscommunicate with surface by means of branched ducts

  • Simple GlandsSimple tubular gland intestinal glands of small intestinesSimple coiled tubular glandEccrine (sweat) glands of skinSimple branched tubular glandMucous glands in small intestineSimple branched alveolar glandSebaceous gland of skin

  • Compound GlandsCompound tubular glandBulbourethral glands of male

    Compound alveolar glandSalivary glands

  • Glandular SecretionsMerocrine glands fluid product that is released through the cell membranesalivary glands, pancreatic glands, certain sweat glands of skinApocrine glandscellular product and portions of the free ends of glandular cells that are pinched off during secretionmammary glands, certain sweat glands of skinHolocrine glandsentire cells that are laden with secretory productssebaceous glands of skin

  • Connective TissuesMost abundant tissue in bodyMany functions, esp. support, protection (against infection), repair, storage (fat), packaging, production of blood cellsWide range of vascularity (mostly, good supplies)Cells widely scattered in an intercellular matrix Fibers and ground substanceTypes of connective tissue vary in their proportions of cells, fibers, and ground substance

  • Connective TissuesMajor Cell TypesFibroblasts widely distributed, large, star-shaped cellssecrete proteins that become fibersMacrophagesMotile cells that are sometimes attached to fibersclear foreign particles from tissues by phagocytosisMast cellslarge, usually located near blood vesselsrelease substances that may help prevent blood clotting (heparin) and promote inflammation (histamine)

  • Connective TissuesConnective Tissue FibersCollagenous fibers (white fibers) thick, threadlike fibers of collagen with great tensile strengthhold structures togetherElastic fibers (yellow fibers)bundles of microfibrils composed of elastin; elasticprovide elastic quality to parts that stretchReticular fibersthin fibers of collagen (major structural protein of body)form supportive networks within tissues

  • Loose (Areolar) Connective TissueBinds organs togetherHolds tissue fluidsLocated beneath the skin, between muscles, and beneath epithelial tissuesCells are mainly fibroblasts, located some distance apart and separated by gel-like ground substance that contains many collagenous and elastic fibers

  • Adipose TissueProtection, insulation, and storage of fatLocated beneath the skin, around the kidneys, behind the eyeballs, and on the surface of the heartContain large fat droplets that cause nuclei to be pushed close to cell membrane

  • Fibrous Connective TissueBinds organs togetherLocated in tendons (connect muscles to bones), ligaments (connect bones to bones at joints), protective white layer of eyeball, and deep layer of skinContains many closely packed, thick, collagenous fibers and a fine network of elastic fibers; few cells -- fibroblastsBlood supply relatively poor -- slow repair

  • Elastic Connective TissueProvides elastic qualityLocated between adjacent vertebrae, in walls of arteries and airwaysConsists mainly of yellow, elastic fibers in parallel strands or branching networks

  • Reticular Connective TissueSupportLocated in walls of liver, spleen, and lymphatic organsComposed of thin, collagenous fibers arranged in a three-dimensional network

  • CartilageSupports parts, provides frameworks and attachments, protects underlying tissues, and forms structural models for many developing bonesChondrocytes occupy small chambers called lacunae and are completely surrounded by matrixEnclosed in a covering of fibrous connective tissue called the perichondrium (location of blood supply)Lacks direct blood supplyThree types: hyaline, elastic, and fibrocartilage

  • Hyaline CartilageSupport, protection, provides frameworkLocated in ends of bones, nose, and rings in walls of respiratory passagesMost common type of cartilageRole in the growth of most bones and repair of bone fractures

  • Elastic CartilageSupport, protection, provides flexible frameworkLocated in framework of external ear and part of larynxMatrix contains many elastic fibers

  • FibrocartilageSupport, protection, shock absorptionLocated between bony parts of backbone, pelvic girdle, and kneeVery tough; many collagenous fibers

  • Bone (Osseous Tissue)Support, protection, provides frameworkLocated in bones of skeletonMost rigid connective tissue, due largely to calcium phosphate and calcium carbonate in matrixProtects vital parts in the cranial and thoracic cavities, and serves as attachment for musclesContains red marrow -- forms blood cellsMatrix deposited in thin layers called lamellaeOsteocytes clustered in concentric circles around osteonic (Haversian) canals

  • BloodCells (red, white, platelets) are suspended in a fluid intercellular matrix called plasma

    Most blood cells form in hematopoietic tissues in red marrow within the hollow parts of certain bones

  • Muscle TissuesContractile; elongated cells (muscle fibers)Three types: skeletal, smooth muscle, cardiac muscleSkeletal muscle tissuefound in muscles attached to bonescontrolled by conscious effort (voluntary muscle tissue)cells have many nuclei, plus alternating light and dark cross-markings called striationsResponsible for moving head, trunk, and limbs, as well as movements involved with facial expressions, writing, talking, singing, chewing, swallowing, and breathing

  • Muscle TissuesSmooth Muscle Tissue Lacks striations; single, centrally located nucleusFound in walls of hollow internal organs (stomach, intestines, urinary bladder, uterus, blood vessels)Involuntary muscle tissueResponsible for moving food through GI tract, constricting blood vessels, and emptying bladderCardiac Muscle Tis