Cardiovascular System I: Heart Anatomy and PhysiologyThe Cardiovascular System DefinedHeart Gross AnatomyThe Heart Wall: Three LayersCoronal Section of Human HeartFlow of Blood Through the HeartSlide 7Operation of Heart ValvesSlide 9Coronary Circulation: Blood Feeding the HeartPosterior View of HeartSlide 12Homeostatic ImbalancesHeart Muscle, ComparedCardiac Muscle Behaves as a Single UnitCardiac Cells Have Simpler T-TubulesSlide 17The Power CycleLonger Refractory Period in Cardiac Cells Prevents Tetanic ContractionsCardiac Stimulation and Contraction is DifferentSlide 21The Heart: Conduction SystemSlide 23Slide 24Filling of Heart Chambers – the Cardiac CycleMedulla Oblongata Cardiac Centers Accelerated and Decelerate Heart BeatElectrocardiograph - A chart Showing Heart Electrical ActivityHeart Voltages and the ECGSlide 29The Heart: Cardiac CycleSlide 31Cells of the S/A Pacemaker Are AutorhythmicSlide 33Slide 34Slide 35Regulation of Stroke VolumeSlide 37Slide 38Heart Rate Affected by Sympathetic and Parasympathetic SystemsSlide 40Slide 41Ductus Arteriosus and Foramen Ovale of the FetusDevelopmental Aspects of the HeartAge-Related Changes Affecting the HeartCongestive Heart Failure (CHF)Slide 46Cardiovascular System I: Heart Anatomy and PhysiologyCardiovascular System DefinedGross Anatomy of the HeartOperation of Heart Valves Systemic and Coronary CirculationCardiac Muscle Cell Anatomy and StimulationElectrical Conduction in the HeartCardiac Cycle and the EKGAutorhythmic Cells of the PacemakerStroke Volume and Contributing FactorsHeart DefectsThe Cardiovascular System DefinedWhat it is:•A closed system of the heart and blood vesselsoThe heart pumps bloodoBlood vessels allow blood to circulate to all parts of the bodyFunction: •Deliver oxygen and nutrients and to remove carbon dioxide and other waste productsHeart Gross Anatomy•Location: Mediastinum of the thorax•Size: As big as your fist•Serous Membrane Coverings: 1. Epicardium (= visceral pericardium) innermost2. Parietal pericardium outermost3. Mediastinal pleura outside thatThe Heart Wall: Three Layers= visceral pericardiumParietalParietal PericardiumVisceral Pericardium (Epicardium)MyocardiumEndocardiumException: In the heart layers, peri- is outside of epi-Coronal Section of Human HeartFlow of Blood Through the HeartCardiovascular System I: Heart Anatomy and PhysiologyCardiovascular System DefinedGross Anatomy of the HeartOperation of Heart Valves Systemic and Coronary CirculationCardiac Muscle Cell Anatomy and StimulationElectrical Conduction in the HeartCardiac Cycle and the EKGAutorhythmic Cells of the PacemakerStroke Volume and Contributing FactorsHeart DefectsOperation of Heart ValvesHeartValves qt.movStenotic and Regurgitant Valve ConditionsHeart sounds movie onlineAV valvesSemilunar valvesCardiovascular System I: Heart Anatomy and PhysiologyCardiovascular System DefinedGross Anatomy of the HeartOperation of Heart Valves Systemic and Coronary CirculationCardiac Muscle Cell Anatomy and StimulationElectrical Conduction in the HeartCardiac Cycle and the EKGAutorhythmic Cells of the PacemakerStroke Volume and Contributing FactorsHeart DefectsCoronary Circulation: Blood Feeding the HeartFigure 18.7aRightventricleRightcoronaryarteryRightatriumRightmarginalarteryPosteriorinterventriculararteryAnteriorinterventriculararteryCircumflexarteryLeftcoronaryarteryAortaAnastomosis(junction ofvessels)LeftventricleSuperiorvena cavaLeft atriumPulmonarytrunkPosterior View of HeartCircumflex arteryCardiovascular System I: Heart Anatomy and PhysiologyCardiovascular System DefinedGross Anatomy of the HeartOperation of Heart Valves Systemic and Coronary CirculationCardiac Muscle Cell Anatomy and StimulationElectrical Conduction in the HeartCardiac Cycle and the EKGAutorhythmic Cells of the PacemakerStroke Volume and Contributing FactorsHeart DefectsHomeostatic ImbalancesAngina pectoris•Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium•Cells are weakened•Erythrocyte sedimentation rate (ESR) is normal in patients who experience only angina.Myocardial infarction (heart attack)•Prolonged coronary blockage due to, e.g. cardiac embolism or throbuso Causes ischemia (lack of O2) leading to muscle death •Areas of cell death are repaired with non-contractile scar tissue•ESR is elevated after an MI; can be used for diagnosisHeart Muscle, ComparedIntercalated disksNucleusDesmosomesGap junctionsIntercalated discs Cardiac muscle cellGap junctions between cardiac cells provide electrical coupling between cells, making the myocardium behave as a single coordinated unit.In smooth and skeletal muscles, depolarization sweeps across the surface of cells. In cardiac muscle, depolarization occurs from within through gap junctions.Cardiac Muscle Behaves as a Single UnitFigure 18.11bNucleusNucleusI bandA bandCardiacmuscle cellSarcolemmaZ discMitochondrionMitochondrionT tubuleSarcoplasmicreticulumI bandIntercalateddisc(b)Cardiac Cells Have Simpler T-TubulesFigure 9.121ActinCross bridge formation.Cocking of myosin head.The power (working) stroke.Cross bridge detachment.Ca2+Myosincross bridgeThick filamentThin filamentADPMyosinPiATPhydrolysisATPATP243ADPPiADPPiFour Step Power Cycle or “Cross Bridge Cycle”The Power CycleA. Masking protein complex (tropomyosin) binds Ca++ released from the SR moves aside to expose head-binding sitesB. Steps of the Power Cycle1. "Cocked" myosin head binds to actin myofilament site 2. Head bends towards the M line (sarcomere center-line), pulling thin filament along and releasing ADP and P (broken ATP) for the power stroke3. ATP binds to the myosin head, causing it to detach4. Myosin head “recocks” as ATP broken down to ADP and PFigure 18.12Long absoluterefractoryperiodLong-lasting tensiondevelopment(contraction)PlateauActionpotentialTime (ms)123 Depolarization isdue to Na+ influx throughfast voltage-gated Na+channels. A positivefeedback cycle rapidlyopens many Na+channels, reversing themembrane potential.Channel inactivation endsthis phase. Plateau phase isdue to Ca2+ influx throughslow Ca2+ channels. Thiskeeps the cell depolarizedbecause few K+ channelsare open. Repolarization is due to Ca2+ channels inactivating and K+channels opening. This allows K+ efflux, which brings the membranepotential back to itsresting voltage.123Tension