Vertebrate Body OrganizationDigestive tube suspended in coelom from mouth toanusBody supported by internalskeleton of jointed bonesVertebrae and Cranium protects nervous systemDiaphragm divides coelom into two partsThoracic cavity: Heart and lungsPeritoneal (abdominal) cavity: Stomach, intestines and liverLevels of organization -cells are organized into tissues, multiple types of tissues areorganized into organs, organs are “organized” into systemsTissue - a group of cells with similar structure and functionsThree fundamental embryonic tissuesEndoderm, mesoderm, ectodermFour adult primary tissues Epithelial, connective, muscle, nerveOrgan - a structural and functional unit composed of different tissuesExample - HeartContains cardiac muscle, connective tissue, epithelial tissueLaced with nerves to regulate heart beatOrgan system- A group of organs that function together to carryout body activitiesExample: Digestive system composed of digestive tract, liver,gall bladder, pancreasHumans contain eleven principal organ systemsTissuesEpithelial TissueCovers Every Surface of the BodyEpidermis derived from ectoderm, comprises outer layer of skin Digestive tract lined with endoderm derived epitheliumBody cavities lined with mesoderm derived epitheliumFunctions of epithelial tissuesProvide selective barrier - facilitate or impede passage of materials into underlying tissuesProtect underlying tissue from dehydration and damageSecrete materials via glandsCharacteristics of epithelial layersCells bound tightly together, one or a few cells thickPossess few blood vessels, transport materials via diffusionReadily regeneratedTwo general classesSimple epithelium - one cell layer thickStratified epithelium - more than one cell layer thickSimple squamous - flat cellswith irregular shape - lining oflungs and capillariesSimple cuboidal: Equal heightand width - lining of glandsand kidney tubuesColumnar: Height greater thanwidth - lining of digestive andrespiratory tractsStratified Squamous - skinand lining of mouthPseudostratified Columnar -lining of respiratory tractand glandsGlands - derived from invaginated epithelia, produce substancesExocrine glands - Connected to epithelium by a ductProduct channeled to outside or to body cavityEndocrine glands - No connection with epithelium, ductlessSecretions called hormones - enter blood at capillariesConnective TissueDerived from embryonic mesodermAll connective tissue has widely-spaced cells imbedded in a non-cellular matrixTwo categoriesConnective tissue proper: Loose and denseSpecial connective tissue: Cartilage, bone, bloodLoose Connective TissueStrengthened by collagen,elastin and/or reticulin fibersFibroblasts secrete collagenand fibrous proteinsCell of loose connective tissueMast cells produce histamine and heparinPhagocytic macrophages defend against invading organismsMay contain adipose (fat) cellsEach fat cell stores a droplet of triglyceridesFound under skin, between organsprovides support, insulation, food storageDense Connective TissueContains tightly packed collagen fibers - arranged in a regular or irregular pattern - has few cells Provides strong and flexible connections and coveringsRegular collagen fibers are lined up in parallelTendons bind muscle to boneLigaments bind bone to boneIrregular collagen fibers - nonparallel orientationTough coverings of organs - kidneys and adrenal glandsPerimysium covers muscles, perineurium covers nerves, periosteum covers bonesSpecialized Connective TissueCartilageHas special ground substance made from a glycoproteinCollagen fibers laid down along lines of stressFirm, flexible tissue that is tough and doesn't stretchMakes up skeleton of jawless fishes, cartilaginous fishes, and parts of skeleton in all other vertebratesCells are chondrocytes - have no direct blood supplyReceive oxygen and nutrients by diffusion from vessels in surrounding tissuesCartilage matrix is not calcified like bone - remains softFound at joints, between vertebrae, nose,earsreduces friction, and absorbs shockdifficult to repairBoneMatrix is collagen fibers hardened with calcium phosphateCells are OsteocytesBone has blood supply through canals, osteocytes have extensions to blood supply in canaliculi (small canals)Many bones in fetus first modeled in cartilageCartilage hardened by calcification, cells die, replaced by bone with living osteocytesEasily repairedBloodContains fluid matrix - plasmaCells -Erythrocytes (red cells) have hemoglobin which carries oxygenLeukocytes (white cells) lack hemoglobinNeutrophils, eosinophils, basophils can be stained Lymphocytes and monocytes have immune functionsThrombocytes (platelets) are fragments of a type of bone marrow cell - function in clottingBlood plasma contains nutrients, metabolic wastes, regulatory molecules, inorganic salts, proteins like fibrinogen and albuminThree types of vertebrate muscle:Smooth, Skeletal and CardiacSkeletal and Cardiac are “striated” muscles have lines running across muscle fibers due to arrangement of actin and myosinMuscle TissueMuscle cells (fibers) havelarge numbers of actinand myosin filaments,specialized for contractionSmooth muscle has more irregulararrangementSmooth muscle is found throughout animal kingdomCells are long and spindle-shaped, each with one nucleusCells organized into sheetsTwo types of contraction occur in smooth muscle:All muscles contract as a unit when stimulated by nerveseen in muscles lining blood vessels, and muscles of irisIndividual cells contract spontaneously (without stimulation)Causes slow, steady contraction of the tissueseen in muscles in the walls of the gutNerves suppress contractions, do not cause itSkeletal MuscleAttached to bones by tendons, contract and cause bones to moveNumerous parallel muscle cells act in concertStronger contractions result when more fibers contractNumber involved depends on stimulation by nervesContain highly ordered arrays of actin and myosin filamentsorganized in bundles called myofibrilsFibers are long and are the result of fusion of cellshave multiple nucleiEach fiber runs the length of the entire muscleCardiac MuscleVertebrate hearts made of specially arranged striated muscle fibersComposed of interconnected cells, each with its own nucleusInterconnections appear as lines called intercalated disksLines are regions where cells are linked by gap junctionsInterconnections allow heart to contract as single unitFunctioning contractile unit is called a myocardiumCertain muscle cells generate