Tissue Types

Tissue TypesJunctionsWhat do you think a junciton is?Hint: Turn left at the junction of 202 and route 1

Way of attaching cells together why necessary?

Pg 69 in text book

Tight Junctionsseal adjacent epithelial cells

How Made- proteins hold the membranes of neighboring cells together

Functions:They prevent the passage of molecules and ions through the space between cells.

Where found:Small intestineSkin

DesmosomesAnchoring junctions

How made- thickening of adjacent PMs are connected by proteins

Function:Prevents cells that are put under stress from being pulled apart

Where found:between skin cellscardiac muscle

Gap Junctions Intercellular channels tunnels between cells

How made- proteins that span the length of the plasma membrane & bond together

Function: lets ions and small molecules move between cells

Where found: cardiac muscle in the heartsome neurons in the brain

Body TissuesTissuesGroups of cells with similar structure and functionFour primary typesEpithelial tissue (epithelium)Connective tissueMuscle tissueNervous tissue

Epithelium CharacteristicsCells fit closely together often sheet-likeThe apical surface = free surfaceThe lower surface of the epithelium rests on a basement membraneAvascular (no blood supply)Regenerate easily if well nourishedSo the function and locations of these tissues would be

Epithelium CharacteristicsFigure 3.17a

Epithelium CharacteristicsCells fit closely together and often form sheetsThe apical surface is the free surface of the tissueThe lower surface of the epithelium rests on a basement membraneAvascular (no blood supply)Regenerate easily if well nourishedSo the function and locations of these tissues would be?

1. Epithelial TissuesLocationsBody coveringsBody liningsGlandular tissueFunctionsProtectionAbsorptionFiltrationSecretion

Classification of EpitheliaNumber of cell layersSimpleone layerStratifiedmore than one layer

Figure 3.17a

Shape of cellsSquamousflattenedCuboidalcube-shapedColumnarcolumn-like

Simple EpitheliaSimple squamousSingle layer of flat cellsUsually forms membranesLines body cavitiesLines lungs and capillaries

Simple EpitheliaSimple cuboidalSingle layer of cube-like cellsCommon in glands and their ductsForms walls of kidney tubulesCovers the ovaries

Simple EpitheliaSimple columnarSingle layer of tall cellsOften includes mucus-producing goblet cellsLines digestive tract

Simple EpitheliaPseudostratified columnarSingle layer, but some cells are shorter than othersOften looks like a double layer of cellsMay function in absorption or secretion

Select 1 of the following types of epithelia and be able to describe its appearance, location in the body, & functionSimple squamousSimple cuboidalSimple ColumnarPseudostratified columnar

Stratified EpitheliaStratified squamousCells at the apical surface are flattenedFound as a protective covering where friction is commonLocationsSkinMouthEsophagus

Stratified EpitheliaStratified cuboidaltwo layers of cuboidal cellsStratified columnarsurface cells are columnar, cells underneath vary in size and shapeStratified cuboidal and columnarRare in human bodyFound mainly in ducts of large glandsStratified EpitheliaTransitional epitheliumShape of cells depends upon the amount of stretchingLines organs of the urinary system

Glandular EpitheliumGlandOne or more cells responsible for secreting a particular productTwo major gland typesEndocrine glandSecretions diffuse into blood vesselsAll secretions are hormones

Exocrine glandSecretions empty through ducts epithelial surfaceInclude sweat and oil glandsCell Sketches!To get used to seeing the tissue types you will be drawing a total of 6 sketches, 2 of which will be examples of epithelial tissue. Find an example of an epithelial tissue under the microscope, critically look at it, then sketch what you seeGrading is based on color (2 for accurate realistic, 1 realistic but the color is a little off, 0 its not colored or does not look realistic at all)Determination of the approximate size (2 if within range, 0 not)Resemblance (4 pts if the sketch looks just like the specimen proper shape, proper size @ mag., attn to detail)Name (1 pt for recording the sketched tissue type)Magnification (1 pt for recording the total magnification at which the specimen was viewed)

Connective TissueFound everywhere in the bodyIncludes the most abundant and widely distributed tissuesFunctionsBinds body tissues togetherSupports the bodyProvides protectionConnective Tissue CharacteristicsVariations in blood supplySome tissue types are well vascularizedSomehave a poor blood supply = ligaments & tendonsare avascular = cartilage Extracellular matrixNon-living material that surrounds living cellsMade of:Ground substance = water mainly with adhesion proteins & polysaccharides Fibers (type and amount vary)Connective Tissue TypesBone (osseous tissue)Composed ofBone cells in lacunae (cavities)Hard matrix of calcium saltsLarge numbers of collagen fibersUsed to protect and support the body

Connective Tissue TypesHyaline cartilageMost common type of cartilageComposed ofAbundant collagen fibersRubbery matrixLocationsLarynxAttach ribs to breast boneEntire fetal skeleton

Connective Tissue TypesElastic cartilageProvides elasticityLocationSupports the external earTip of nose

FibrocartilageHighly compressibleLocationForms cushion-like discs between vertebrae

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Connective Tissue Types- DenseDense connective tissue (fibrous tissue)Form strong rope-like structuresMain matrix element = collagen fibersLocationsTendonsattach skeletal muscle to boneLigamentsattach bone to bone at jointsDermislower layers of the skin

Connective Tissue Types- LooseAreolar tissueMost widely distributed connective tissueSoft, pliable tissue like cobwebsFunctions as a packing tissueContains all fiber typesCan soak up excess fluid (causes edema)Connective Tissue Types- LooseAdipose tissueMatrix is an areolar tissue in which fat globules predominateMany cells contain large lipid depositsFunctionsInsulates the bodyProtects some organsServes as a site of fuel storage

Connective Tissue Types- LooseReticular connective tissueDelicate network of interwoven fibersForms stroma (internal supporting network) of lymphoid organsLymph nodesSpleenBone marrow

Connective Tissue TypesBloodFluid matrix = blood plasmaFibers are visible during clotting onlyTransports materials

Cell Sketches!To get used to seeing the tissue types you will be drawing a total of 6 sketches, 2 of which will be examples of epithelial tissue. Find an example of an epithelial tissue under the microscope, critically look at it, then sketch what you seeGrading is based on color (2 for accurate realistic, 1 realistic but the color is a little off, 0 its not colored or does not look realistic at all)Determination of the approximate size (2 if within range, 0 not)Resemblance (4 pts if the sketch looks just like the specimen proper shape, proper size @ mag., attn to detail)Name (1 pt for recording the sketched tissue type)Magnification (1 pt for recording the total magnification at which the specimen was viewed)

Muscle TissueFunction is to produce movementThree typesSkeletal muscleCardiac muscleSmooth muscle

Muscle Tissue TypesSkeletal muscleUnder voluntary controlContracts to pull on bones or skinCharacteristics of skeletal muscle cellsStriatedMultinucleate (more than one nucleus)Long, cylindrical

Muscle Tissue TypesCardiac muscleUnder involuntary controlFound only in the heartCharacteristics of cardiac muscle cellsCells are attached intercalated disksStriatedOne nucleus per cell

Muscle Tissue TypesSmooth muscleUnder involuntary muscleFound in walls of hollow organs such as stomach, uterus, and blood vesselsCharacteristics of smooth muscle cellsNo visible striationsOne nucleus per cellSpindle-shaped cells

Nervous TissueComposed of neurons and nerve support cellsFunction is to send impulses to other areas of the bodyIrritabilityresponds to a stimulus (electrical)Conductivityability to carry an electrical current

Cell Sketches!To get used to seeing the tissue types you will be drawing a total of 6 sketches, 2 of which will be examples of epithelial tissue. Find an example of an epithelial tissue under the microscope, critically look at it, then sketch what you seeGrading is based on color (2 for accurate realistic, 1 realistic but the color is a little off, 0 its not colored or does not look realistic at all)Determination of the approximate size (2 if within range, 0 not)Resemblance (4 pts if the sketch looks just like the specimen proper shape, proper size @ mag., attn to detail)Name (1 pt for recording the sketched tissue type)Magnification (1 pt for recording the total magnification at which the specimen was viewed)

Tissue Repair (Wound Healing)RegenerationReplacement of destroyed tissue by the same kind of cellsFibrosisRepair by dense (fibrous) connective tissue (scar tissue)Determination of methodType of tissue damagedSeverity of the injuryEvents in Tissue RepairCapillaries become very permeableIntroduce clotting proteinsA clot walls off the injured areaFormation of granulation tissueGrowth of new capillariesRebuild collagen fibersRegeneration of surface epitheliumScab detachesRegeneration of TissuesTissues that regenerate easilyEpithelial tissue (skin and mucous membranes)Fibrous connective tissues and boneTissues that regenerate poorlySkeletal muscleTissues that are replaced largely with scar tissueCardiac muscleNervous tissue within the brain and spinal cord