Lab Activity 23Cardiac AnatomyPortland Community CollegeBI 2322Cardiac Muscle HistologyBranching cellsIntercalated disc: contains many gap junctions connecting the adjacent cell cytoplasm, creates a functional syncytiumOnce central nucleus3External View4Position in ThoraxBase: Where the Great Vessels enter and exitApex: points inferiorly, anteriorly and to the left5Position of HeartHint: Nipples are at the 4thintercostal spaceApex at 5thintercostal space during ventricular systole (contraction)Point of Maximum Impulse: PMI is the apex on surface anatomy6Heart Wall7RightAtriumRightVentricle LeftVentricleAuriclesAnterior View Posterior ViewLeftVentricleRightVentricleRightAtriumLeftAtriumChambers: External View8Heart Chambers• Papillary musclesanchor the valves in the ventricles• Trabeculae carneaeare the “waffle like” muscular ridges in the ventriclesRightAtriumRightVentriclePapillary musclesLeftVentricleTrabeculae carneaeLeftAtriumInterventricular septum9VesselsSuperior Vena CavaInferior Vena CavaCoronary SinusPulmonary trunkLeft Pulmonary ArteryRight Pulmonary Artery (branches)10Vessels: Posterior ViewRightAtriumSuperior Vena CavaCoronary SinusInferior Vena CavaLeft Pulmonary ArteryRight Pulmonary Artery11VesselsAscending AortaAortic ArchLeft Pulmonary Vein(Right not visible)Descending Aorta12Vessels: Posterior ViewLeftAtriumAortic ArchLeft Pulmonary VeinsRight Pulmonary Veins13ValvesRight Side of Heart• Tricuspid: Between Right Atrium and Right Ventricle• Pulmonary: Between Right Ventricle and Pulmonary TrunkLeft Side of Heart• Mitral: Between Left Atrium and Left Ventricle• Aortic Valve: Between Left Ventricle and AortaChordae Tendineae are only on the Tricuspid and Mitral Valves (valves between atrium and ventricle)14ValvesTricuspidPulmonaryMitralAortic (behind the pulmonary trunk)Chordae tendineaeConsist of 2-3 flaps of connective tissue covered by endothelium15•When the ventricles are relaxed (diastole), the valves between the atria and ventricles are Open: Mitral and Tricuspid•The valves leading out of the heart are Closed: Pulmonary and Aortic valves16•When the ventricles are contracted (systole), the valves between the atria and ventricles are Closed: Mitral and Tricuspid•The valves leading out of the heart are Open: Pulmonary and Aortic valves17Fetal Circulation RemnantsFossa Ovalis18Fetal Circulation RemnantsLigamentum Arteriosum19Conduction System20Step 1SA node activity and atrial activation beginsTime= 0Step 2Stimulus spreads across the atrial surfaces and reaches the AV nodeTime= 50 msecImpulseConduction21ImpulseConductionStep 3There is a 100-msec delay at the AV node. Atrial contraction beginsTime= 150 msec22ImpulseConductionStep 4The impulse travels along the interventricular septum within the AV bundle and the bundle branches to the Purkinje fibers to the papillary muscles of the right ventricleTime= 175 msec23ImpulseConductionStep 5The impulse is distributed by Purkinje fibers and relayed throughout the ventricular myocardium. Atrial contraction is completed, and ventricular contraction beginsTime= 225 msec24Coronary Circulation: Anterior ViewRight Coronary ArteryLeft Coronary ArteryCircumflex ArteryLeft Anterior DescendingGreat Cardiac Vein25Coronary Circulation: Posterior ViewMarginal ArteryCircumflex ArteryMarginal ArteryRight Coronary ArteryPosterior Descending ArteryMiddle Cardiac VeinPosterior Cardiac VeinCoronary Sinus2627Terminology• Systole: The contraction of the heart muscle, especially the ventricle• Diastole: The relaxation of the heart muscle.• Cardiac Cycle: A complete heartbeat consisting of systole and diastole of both atria plus systole and diastole of both ventricles.28Heart Sounds• One heart beat is described as “lubb-dupp”• S1 “lubb”: This is the closing of the AV valves: Mitral and Tricuspid• Marks the beginning of ventricular contraction (beginning of systole)• S2 “dupp”: This is the closing of the Pulmonary and Aortic valves• Occurs at the beginning of ventricular filling (end of systole)29Auscultation• The sound of the valve closing radiates in the direction the blood is flowing.• The actual location of the valve is not the best place to listen for it.3031The