Tissues are:Tissues are: Collections of specialized cells and cell Collections of specialized cells and cell

products organized to perform a limited products organized to perform a limited number of functionsnumber of functions Histology = study of tissuesHistology = study of tissues

The four tissue types are:The four tissue types are: EpithelialEpithelial ConnectiveConnective MuscularMuscular NervousNervous

Tissues and tissue typesTissues and tissue types

Includes glands and epitheliumIncludes glands and epithelium Glands are secretoryGlands are secretory

Is avascularIs avascular Forms a protective barrier that Forms a protective barrier that

regulates permeabilityregulates permeability Cells may show polarityCells may show polarity

Epithelial tissueEpithelial tissue

Physical protectionPhysical protection Control permeabilityControl permeability Provide sensationProvide sensation Produce specialized secretionsProduce specialized secretions

Functions of epitheliumFunctions of epithelium

Perform secretory functionsPerform secretory functions Perform transport functionsPerform transport functions Maintain physical integrityMaintain physical integrity Ciliated epithelia move materials Ciliated epithelia move materials

across their surfaceacross their surface

Specializations of Specializations of epitheliumepithelium

The Polarity of Epithelial The Polarity of Epithelial CellsCells

Cells attach via cell adhesion Cells attach via cell adhesion molecules (CAM)molecules (CAM)

Cells attach at specialized cell Cells attach at specialized cell junctionsjunctions Tight junctionsTight junctions DesmosomesDesmosomes Gap junctionsGap junctions

Maintaining the integrity Maintaining the integrity of epitheliumof epithelium

Intercellular connectionsIntercellular connections

Basal lamina attaches to underlying Basal lamina attaches to underlying surfacesurface Lamina lucidaLamina lucida Lamina densaLamina densa

Germinative cells replace short-lived Germinative cells replace short-lived epithelial cellsepithelial cells

Structure of typical Structure of typical epitheliumepithelium

Number of cell layersNumber of cell layers SimpleSimple StratifiedStratified

Shape of apical surface cellsShape of apical surface cells SquamousSquamous CuboidalCuboidal ColumnarColumnar

Classification of epitheliaClassification of epithelia

Squamous EpitheliaSquamous Epithelia

Cuboidal EpitheliaCuboidal Epithelia

Cuboidal EpitheliaCuboidal Epithelia

Transitional EpitheliumTransitional Epithelium

Columnar EpitheliaColumnar Epithelia

Columnar EpitheliaColumnar Epithelia

Columnar EpitheliaColumnar Epithelia

Exocrine glandsExocrine glands Secrete through ducts onto the surface of Secrete through ducts onto the surface of

the glandthe gland Endocrine glandsEndocrine glands

Release hormones into surrounding fluidRelease hormones into surrounding fluid

Glandular epitheliaGlandular epithelia

Merocrine (product released through Merocrine (product released through exocytosis)exocytosis)

Apocrine (involves the loss of both Apocrine (involves the loss of both product and cytoplasm)product and cytoplasm)

Holocrine (destroys the cell)Holocrine (destroys the cell)

Glandular secretions can Glandular secretions can be:be:

Mechanisms of Mechanisms of Glandular SecretionGlandular Secretion

UnicellularUnicellular Individual secretory cellsIndividual secretory cells

MulticellularMulticellular Organs containing glandular epitheliumOrgans containing glandular epithelium Classified according to structureClassified according to structure

GlandsGlands

A Structural Classification A Structural Classification of Exocrine Glandsof Exocrine Glands

Establishing a structural frameworkEstablishing a structural framework Transporting fluids and dissolved materialsTransporting fluids and dissolved materials Protecting delicate organsProtecting delicate organs Supporting, surrounding and interconnecting tissuesSupporting, surrounding and interconnecting tissues Storing energy reservesStoring energy reserves Defending the body from microorganismsDefending the body from microorganisms

Connective tissue Connective tissue functions: functions:

A Classification of A Classification of Connective TissuesConnective Tissues

Specialized cellsSpecialized cells MatrixMatrix

Composed of extracellular protein fibers and a Composed of extracellular protein fibers and a ground substanceground substance

Connective tissues Connective tissues contain contain

Contains varied cell populationsContains varied cell populations Contains various fiber typesContains various fiber types A syrupy ground substanceA syrupy ground substance

Connective tissue proper Connective tissue proper

Fluid connective tissueFluid connective tissue

Contains a distinctive cell populationContains a distinctive cell population Watery ground substance with Watery ground substance with

dissolved proteinsdissolved proteins Two typesTwo types

BloodBlood LymphLymph

Less diverse cell populationLess diverse cell population Dense ground substanceDense ground substance Closely packed fibersClosely packed fibers Two typesTwo types

CartilageCartilage BoneBone

Supporting connective Supporting connective tissuestissues

Contains fibers, a viscous ground Contains fibers, a viscous ground substance, and a varied cell substance, and a varied cell populationpopulation FibroblastsFibroblasts MacrophageMacrophage AdipocytesAdipocytes Mesenchymal cellsMesenchymal cells MelanocytesMelanocytes Mast cellsMast cells LymphocytesLymphocytes MicrophagesMicrophages

Connective tissue properConnective tissue proper

Three types of fiberThree types of fiber Collagen fibersCollagen fibers Reticular fibersReticular fibers Elastic fibersElastic fibers

Connective tissue properConnective tissue proper

Classified as loose or denseClassified as loose or dense LooseLoose

Embryonic mesenchyme, mucous Embryonic mesenchyme, mucous connective tissues connective tissues

Areolar tissueAreolar tissue Adipose tissueAdipose tissue Reticular tissueReticular tissue

DenseDense Dense regular CTDense regular CT Dense irregular CTDense irregular CT

Connective tissue properConnective tissue proper

The Cells and Fibers of The Cells and Fibers of Connective Tissue ProperConnective Tissue Proper

Connective Tissue in Connective Tissue in EmbryosEmbryos

Adipose and Reticular Adipose and Reticular TissuesTissues

Dense Connective Dense Connective TissuesTissues

Dense Connective Dense Connective TissuesTissues

Dense Connective Dense Connective TissuesTissues

Distinctive collections of cells in a Distinctive collections of cells in a fluid matrixfluid matrix

BloodBlood Formed elements and plasmaFormed elements and plasma

Red blood cells, white blood cells and plateletsRed blood cells, white blood cells and platelets Arteries carry blood away, veins carry to Arteries carry blood away, veins carry to

the heartthe heart Capillaries allow diffusion into the Capillaries allow diffusion into the

interstitial fluid interstitial fluid LymphLymph

Interstitial fluid entering the lymphatic Interstitial fluid entering the lymphatic vesselsvessels

Fluid connective tissuesFluid connective tissues

Formed Elements of the Formed Elements of the BloodBlood

Cartilage and bone support the rest of Cartilage and bone support the rest of the bodythe body

CartilageCartilage Grows via interstitial and appositional Grows via interstitial and appositional

growthgrowth Matrix is a firm gel containing chondroitin Matrix is a firm gel containing chondroitin

sulfatesulfate Cells called chondrocytesCells called chondrocytes Cells found in lacunaeCells found in lacunae Perichondrium separates cartilage from Perichondrium separates cartilage from

surrounding tissuessurrounding tissues Three types: hyaline, elastic and Three types: hyaline, elastic and

fibrocartilagefibrocartilage

Supporting connective Supporting connective tissuestissues

The Perichondrium and The Perichondrium and Types of CartilageTypes of Cartilage

The Perichondrium and The Perichondrium and Types of CartilageTypes of Cartilage

The Perichondrium and The Perichondrium and Types of CartilageTypes of Cartilage

Has osteocytesHas osteocytes Depend on diffusion through canaliculi Depend on diffusion through canaliculi

for nutrientsfor nutrients Little ground substanceLittle ground substance Dense mineralized matrixDense mineralized matrix Surrounded by periosteumSurrounded by periosteum

Bone, or osseus tissueBone, or osseus tissue

BoneBone

Form a barrierForm a barrier Composed of epithelium and Composed of epithelium and

connective tissueconnective tissue Four typesFour types

CutaneousCutaneous SynovialSynovial SerousSerous MucousMucous

Membranes are simple Membranes are simple organsorgans

MembranesMembranes

Line cavities that communicate with Line cavities that communicate with the exteriorthe exterior

Contain lamina propriaContain lamina propria

Mucous membranesMucous membranes

Line sealed internal cavitiesLine sealed internal cavities Form transudateForm transudate

Serous membranesSerous membranes

Cutaneous membraneCutaneous membrane Covers the body surfaceCovers the body surface

Synovial membraneSynovial membrane Incomplete lining within joint cavitiesIncomplete lining within joint cavities

Network of connective tissue proper Network of connective tissue proper consisting ofconsisting of Superficial fasciaSuperficial fascia Deep fasciaDeep fascia Subserous fasciaSubserous fascia

Organs and systems are Organs and systems are interconnectedinterconnected

The FasciaeThe Fasciae

Specialized for contractionSpecialized for contraction Three typesThree types

SkeletalSkeletal CardiacCardiac SmoothSmooth

Muscle tissueMuscle tissue

Muscle TissueMuscle Tissue

Muscle TissueMuscle Tissue

Muscle TissueMuscle Tissue

Cells are multinucleateCells are multinucleate Striated voluntary muscleStriated voluntary muscle Divides via satellite cellsDivides via satellite cells

Skeletal muscleSkeletal muscle

Cardiocytes occur only in the heartCardiocytes occur only in the heart Striated involuntary muscleStriated involuntary muscle Relies on pacemaker cells for regular Relies on pacemaker cells for regular

contractioncontraction

Cardiac muscleCardiac muscle

Non-striated involuntary muscleNon-striated involuntary muscle Can divide and regenerateCan divide and regenerate

Smooth muscle tissueSmooth muscle tissue

Conducts electrical impulsesConducts electrical impulses Conveys information from one area to Conveys information from one area to

anotheranother

Neural tissueNeural tissue

NeuronsNeurons Transmit informationTransmit information

NeurogliaNeuroglia Support neural tissueSupport neural tissue Help supply nutrients to neuronsHelp supply nutrients to neurons

Neural tissue cellsNeural tissue cells

Neural TissueNeural Tissue

Cell bodyCell body DendritesDendrites Axon (nerve fiber)Axon (nerve fiber)

Carries information to other neuronsCarries information to other neurons

Neural anatomyNeural anatomy

Injured tissues respond in Injured tissues respond in coordinated fashioncoordinated fashion

Homeostasis restored by Homeostasis restored by inflammation and regenerationinflammation and regeneration

Inflammation and Inflammation and regenerationregeneration

Isolates injured areaIsolates injured area Damaged cells, tissue components and Damaged cells, tissue components and

dangerous microorganisms removeddangerous microorganisms removed Infection avoidedInfection avoided

Regeneration restores normal functionRegeneration restores normal function

Inflammatory responseInflammatory response

An Introduction to An Introduction to InflammationInflammation

Change with ageChange with age Repair and maintenance less efficientRepair and maintenance less efficient Structure alteredStructure altered Chemical composition alteredChemical composition altered

Aging and tissue repairAging and tissue repair

Aging and cancer Aging and cancer incidenceincidence

Incidence of cancer increases with Incidence of cancer increases with ageage

70-80% of all cases due to exposure 70-80% of all cases due to exposure to chemicals or environmental to chemicals or environmental factorsfactors

Changes in a Tissue Changes in a Tissue under Stressunder Stress