Ch. 4 Connective Tissue Muscle Tissue

Ch. 4 Connective TissueMuscle Tissue

Figure 4-18 Muscle TissueSkeletal Muscle TissueCardiac Muscle TissueSmooth Muscle TissueSmooth muscleCardiac muscleSkeletal muscleCells are long, cylindrical, striated, and multinucleate.LOCATIONS: Combinedwith connective tissuesand neural tissue inskeletal musclesFUNCTIONS: Moves orstabilizes the position ofthe skeleton; guardsentrances and exits tothe digestive,respiratory, and urinarytracts; generates heat;protects internal organsCells are short, branched,and striated, usually with asingle nucleus; cells areinterconnected byintercalated discs.FUNCTIONS:Circulates blood;maintains blood(hydrostatic) pressureLOCATION: HeartCells are short, spindle-shaped, andnonstriated, with a single, centralnucleus.LOCATIONS: Found inthe walls of blood vesselsand in digestive, respiratory,urinary, and reproductive organsFUNCTIONS: Moves food,urine, and reproductive tractsecretions; controlsdiameter of respiratorypassageways; regulatesdiameter of blood vesselsNucleiMusclefiberStriationsLM 180LM 180LM 450LM 235NucleusCardiacmusclecellsIntercalateddiscsStriationsNucleusSmoothmusclecell2Three types of muscleSkeletal, smooth and cardiac muscleEpithelia lined outside and inside of body and cavitiesConnective supported and connected partsMajor function of many organs and organ systems involves MOVEMENT; either of a substance (digestive system and circulatory system) or of the body (skelato-muscular)Muscle cells distinct organelles and propertiesMuscle cells and muscle tissue are specialized to CONTRACTSkeletal MuscleVery long, very slender muscle cells called muscle fibersMultinucleateCan divideMuscle usually grows because satellite stem cells called myosatellite cells divideCan repair after injuryFibers made of proteins called actin and myosinContractileAppear banded or striatedVoluntary Most predominant form of tissue in human bodyHeld together by elastin and collagen and blended with tendonsWhich are attached to bones, contraction moves bone at joint ( think hinge)

Figure 4-18a Muscle TissueSkeletal Muscle TissueSkeletal muscleCells are long, cylindrical, striated, and multinucleate.LOCATIONS: Combinedwith connective tissuesand neural tissue inskeletal musclesFUNCTIONS: Moves orstabilizes the position ofthe skeleton; guardsentrances and exits tothe digestive,respiratory, and urinarytracts; generates heat;protects internal organsNucleiMusclefiberStriationsLM 1805Cardiac MuscleLocated only in the heartCardiocytesMost with one nucleusProminent striationsBranching highly interconnected; fan out of message to contract = heart beatConnections are called intercalated discs and contain desmosomes, proteoglycans and gap junctions = cells are locked tight together and ions responsible for beat can flow throughLimited ability to repair damaged/dead cellspace maker cells vs nerve cellsStriated INVOLUNTARY

Figure 4-18b Muscle TissueCardiac Muscle TissueCardiac muscleCells are short, branched,and striated, usually with asingle nucleus; cells areinterconnected byintercalated discs.FUNCTIONS:Circulates blood;maintains blood(hydrostatic) pressureLOCATION: HeartLM 450NucleusCardiacmusclecellsIntercalateddiscsStriations7Smooth MuscleLocated in walls of blood vessels and hollow organs like intestine and bladderOften in layersSmaller cells; tapered at each end with oval nucleusBecause of nuclei, they can regenerate after injuryActin and myosin arranged differently no striationsUnder nervous control, but not conscious control = 8 m of intestine and miles of blood vessels would be a lot to think about!Non-striated, involuntary

Figure 4-18c Muscle TissueSmooth muscleCells are short, spindle-shaped, andnonstriated, with a single, centralnucleus.LOCATIONS: Found inthe walls of blood vesselsand in digestive, respiratory,urinary, and reproductive organsFUNCTIONS: Moves food,urine, and reproductive tractsecretions; controlsdiameter of respiratorypassageways; regulatesdiameter of blood vesselsLM 235NucleusSmoothmusclecellSmooth Muscle Tissue9Nervous TissueNeural or Nervous TissueConducting electrical impulses98% within brain and spinal cord (CNS)Neurons = nerve cellsMany without nucleiVery limited ability to repairNeuroglia = supporting cells; connective tissue; glueSupportSupply nutrientsSome repairElectrical impulses are transmembrane potentials

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Figure 4-19 Neural TissueNEURONSNEUROGLIA (supporting cells) Maintain physical structure Repair tissue framework Perform phagocytosis Regulate the composition of theinterstitial fluid surrounding neuronsof tissuesafter injury Provide nutrients to neuronsAxonNucleolusNucleusof neuronDendrites(contacted byother neurons)Axon (conductsinformation toother cells)Cell bodyDendritesMitochondrionNucleusMicrofibrils andmicrotubulesNucleolusCell body (contains nucleusand major organelles)A representative neuron(sizes and shapes vary widely)Contact with other cellsNuclei of neurogliaLM 60012Transmembrane PotentialCell membranes have an associated electrical potentialThis means that the ion concentrations of the cytoplasm and the extracellular fluid are slightly different and there is a charge difference from one side of the CM to the other sideLong, thin wires = rapid conductionMeasured in millivolts (1/1000 th of a volt)mV / microsecond ( 10-6 or 1/1000th of a millisecond)Nerve impulses temporarily reverse this charge or polarityNa, K, Ca, ClMust be restored before it can refire - tonus/ spasm