Slide 1The HeartThe Cardiovascular SystemThe Heart: Heart WallSlide 5The Heart WallMyocardium = Muscular Wall =Cardiac MuscleExternal Anatomy - AnteriorWhat is the path of blood flow through the heart, and what are the major blood vessels, chambers, and heart valves?Heart ValvesSlide 12Slide 13AV Valve MechanicsThe Heart: ChambersBlood Flow Through HeartThe Vena CavaThe Heart: Associated Great VesselsReturn from Pulmonary CircuitBlood CirculationSlide 21Dichotomous Functions for Left & Right Side of HeartSlide 23Slide 24What are the Heart Valves?What Can Go Wrong With Valves?The Heart: ValvesSlide 28Slide 29Mitral Valve ProlapseREGURGITANT VALVEMechanism of Cardiac ContractionHEART MUSCLE AND CONTRACTION: THE NATURE OF CARDIAC MUSCLEThe Vertebrate Heart : Its Heartbeat..How ? Where does it start?THE HEART HAS 2 Types of tissue:Where Does Calcium Come From?The Cardiac CycleCardiac Muscle CellsStructure of Cardiac Muscle CellCardiac Cells vs. Skeletal FibersMetabolism of Cardiac MuscleCardiac Muscle CellsRemember The Desmosome?GAP JUNCTIONS?Plasma Membrane W/ Gap JunctionsWhat is MYOGLOBIN? ROLE HERE?MyoglobinCharacteristics of Cardiac Muscle CellsCardiac Conduction SystemStructure of Cardiac MuscleHeart ContractionsThe Conducting SystemStructures of the Conducting SystemPrepotentialImpulse Conduction through the HeartThe Sinoatrial (SA) NodeThe Atrioventricular (AV) NodeThe AV Bundle4. The Purkinje FibersAbnormal Pacemaker FunctionContractile CellsWhat events take place during an action potential in cardiac muscle?Slide 632 Phases of the Cardiac CyclePhases of the Cardiac Cycle4 Phases of the Cardiac CycleWhat electrical events are associated with a normal electrocardiogram?Electrocardiogram (ECG or EKG)Visualizing the WavesThe Waves of the ECGElectrocardiogram (ECG)Normal Electrocardiogram (ECG)Aberrations from the Normal ECGSlide 74Filling of Heart Chambers – the Cardiac CycleTHE CARDIOVASCULAR SYSTEMThe HeartFigure 11.1The Cardiovascular SystemA closed system of the heart and blood vesselsThe heart pumps bloodBlood vessels allow blood to circulate to all parts of the bodyThe function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste productsThe Heart: Heart WallThree layersEpicardiumOutside layerThis layer is the parietal pericardiumConnective tissue layerMyocardiumMiddle layerMostly cardiac muscleEndocardiumInner layerEndotheliumMyocardium is criss-crossed and arranged in figure 8-shaped bundles shown in (b). MYOCARDIUM IS CRISS-CROSSEDThe Heart WallFigure 20–4Myocardium = Muscular Wall =Cardiac Muscle Intercalated disks convey the force of contraction from cell to cell and propagate action potentialsMuscle tissue is CONTRACTILE tissue.Cardiac Muscle Cells are Small, w/ a single nucleus. Short cells. Involuntary contractionsExternal Anatomy - AnteriorWhat is the path of blood flow through the heart, and what are the major blood vessels, chambers, and heart valves?Heart ValvesAtrioventricular (AV) valvesright AV valve has 3 cusps (tricuspid valve)left AV valve has 2 cusps (mitral, bicuspid valve)chordae tendineae - cords connect AV valves to papillary muscles (on floor of ventricles)Semilunar valves - control flow into great arteriespulmonary: right ventricle into pulmonary trunkaortic: from left ventricle into aortaHeart ValvesHeart ValvesAV Valve MechanicsVentricles relaxpressure dropssemilunar valves closeAV valves openblood flows from atria to ventriclesVentricles contractAV valves closepressure risessemilunar valves openblood flows into great vesselsThe Heart: ChambersRight and left side act as separate pumpsFour chambersAtriaReceiving chambersRight atriumLeft atriumVentriclesDischarging chambersRight ventricleLeft ventricleFigure 11.2cBlood Flow Through HeartThe Vena CavaDelivers systemic circulation to right atrium Superior vena cava:receives blood from head, neck, upper limbs, and chestInferior vena cava: receives blood from trunk, and viscera, lower limbsThe Heart: Associated Great VesselsAortaLeaves left ventriclePulmonary arteriesLeave right ventricleVena cavaEnters right atriumPulmonary veins (four)Enter left atriumReturn from Pulmonary CircuitBlood gathers into left and right pulmonary veins Pulmonary veins deliver to left atriumBlood from left atrium passes to left ventricle through left atrioventricular (AV) valve2-cusp bicuspid valve or mitral valveBlood CirculationFigure 11.3DOUBLE PUMPDichotomous Functions for Left & Right Side of HeartRight Side : Collects oxygen-poor blood from the body and brain and pumps to the lungs where it picks up oxygen. This is called pulmonary circulation.Left Side: Collects oxygen-rich blood, which has just passed through the lungs, and pumps it to the rest of the body and brain. The is called systemic circulation.Blood CirculationFigure 11.3What are the Heart Valves? These ensure that blood flows in one direction..no back flow2 are the atrioventricular valves and 2 are the semilunar valves.Artioventricular: Bicuspid has 2 cusps or valves and Tricupid has 3. Semilunar valves are found within entrances of arteries extending from ventriclesPULMONARY semilunar and AORTIC semilunarWhat Can Go Wrong With Valves?Scarred Valves Sometimes become STENOTIC (THEY CUFFS BECOME STIFFED AND CONSTRICT…DON”T OPEN) Valvular StenosisHeart then overworks to force blood through and valves become enlarged Backflow (regurgitation) through these new incompetent valves creates turbulence or HEART MURMER.The Heart: ValvesAllow blood to flow in only one directionFour valvesAtrioventricular valves – between atria and ventriclesBicuspid valve (left)(also called Mitral)Tricuspid valve (right) Semilunar valves between ventricle and arteryPulmonary semilunar valveAortic semilunar valveThe Heart: ValvesValves open as blood is pumped throughHeld in place by chordae tendineae (“heart strings”)Close to prevent backflowMitral Valve ProlapseOne or both of the bicuspid valve cusps bulge into the atrium during ventricar contraction. Hereditary: 1in 40, more in womenIn many cases no serious problems but may cause chest pain , fatigue and shortness of breath.REGURGITANT VALVEHEART VALVES THAT STAY OPENOR ARE TOO WIDE AND LET