Advanced BiologyAdvanced BiologyHeartHeart

Size, Shape, LocationSize, Shape, LocationFistFistHollow, cone shapedHollow, cone shapedMediastinum, Rests on Mediastinum, Rests on

diaphragm, posterior to diaphragm, posterior to sternum, Lungs on each sternum, Lungs on each sideside

Size, Shape, LocationSize, Shape, Location2/3 lie to left of midsternal 2/3 lie to left of midsternal

linelinePoints toward right Points toward right

shoulder and left hip shoulder and left hip (apex, PMI)(apex, PMI)

Structure/Function 4 Structure/Function 4 ChambersChambers

2 Superior Atria2 Superior Atria2 Inferior Ventricles2 Inferior VentriclesDivided by Divided by

interatrial/interventricular interatrial/interventricular septumseptum

Structure/Function 4 Structure/Function 4 ChambersChambers

Most Mass in Right and Left Most Mass in Right and Left Ventricles; pumping chambersVentricles; pumping chambers

Right= Forms most of the Right= Forms most of the anterior surfaceanterior surface

Left= Forms inferoposterior Left= Forms inferoposterior aspect. Much more muscular!aspect. Much more muscular!

Structure/Function 4 Structure/Function 4 ChambersChambers

Posterior Atrial walls are Posterior Atrial walls are smoothsmooth

Anterior Atrial walls are rigid Anterior Atrial walls are rigid with bundles of muscle tissuewith bundles of muscle tissue

Atria are the Receiving Atria are the Receiving chambers; thin walledchambers; thin walled

Pathway of BloodPathway of BloodBlood Flow through chambersBlood Flow through chambersRight Atrium – Superior Vena Right Atrium – Superior Vena

Cava, Inferior Vena Cava, Cava, Inferior Vena Cava, Coronary SinusCoronary Sinus

Left Atrium – 4 Pulmonary Left Atrium – 4 Pulmonary veins pump blood backveins pump blood back

Pathway of BloodPathway of BloodRight Ventricle – pumps Right Ventricle – pumps

blood to pulmonary trunk blood to pulmonary trunk (goes to lungs)(goes to lungs)

Left Ventricle – pumps Left Ventricle – pumps blood to Aorta, then out to blood to Aorta, then out to bodybody

Pathway of BloodPathway of BloodValves – Atrioventricular Valves – Atrioventricular

(AV)(AV)Right – TricuspidRight – TricuspidLeft – BicuspidLeft – BicuspidSemilunar valves in Semilunar valves in

pulmonary trunk/aortapulmonary trunk/aorta

Pathway of BloodPathway of BloodPulmonary Circuit – Pulmonary Circuit –

Pulmonary veins have Pulmonary veins have blood with oxygenblood with oxygen

Pulmonary arteries have Pulmonary arteries have blood without oxygenblood without oxygen

Pathway of BloodPathway of BloodSystemic Circuit – Arteries Systemic Circuit – Arteries

have blood with oxygenhave blood with oxygenVeins have blood without Veins have blood without

oxygenoxygenSee page 662See page 662

Major BranchesMajor BranchesCoronary Circulation – Coronary Circulation –

supply blood to the heartsupply blood to the heartLeft Coronary – runs to left Left Coronary – runs to left

side and divides into two side and divides into two partsparts

Major BranchesMajor BranchesAnterior Interventricular Anterior Interventricular

arteryarterySupplies blood to Supplies blood to

interventricular septum interventricular septum and anterior walls of and anterior walls of ventriclesventricles

Major BranchesMajor BranchesCircumflex arteryCircumflex arterySupplies blood to the left Supplies blood to the left

atrium and posterior wall atrium and posterior wall of left ventricleof left ventricle

Major BranchesMajor BranchesRight Coronary – Runs to Right Coronary – Runs to

the right and also divides the right and also divides into two partsinto two parts

Major BranchesMajor BranchesMarginal Artery – lateral part Marginal Artery – lateral part

of right side of heart (atrium)of right side of heart (atrium)Posterior interventricular Posterior interventricular

artery – Runs to the apex, artery – Runs to the apex, supplies posterior ventricle supplies posterior ventricle wallswalls

Major BranchesMajor BranchesCardiac Veins – 1 major, 3 Cardiac Veins – 1 major, 3

minor that dump intominor that dump intoCoronary Sinus – empties Coronary Sinus – empties

blood into the right blood into the right atrium.atrium.

Located on Posterior sideLocated on Posterior side

Major BranchesMajor BranchesGreat Cardiac Vein – Found in Great Cardiac Vein – Found in

the anterior interventricular the anterior interventricular sulcus (groove)sulcus (groove)

Middle Cardiac Vein – In Middle Cardiac Vein – In posterior interventricular posterior interventricular sulcussulcus

Major BranchesMajor BranchesSmall Cardiac Vein – runs Small Cardiac Vein – runs

along heart’s right inferior along heart’s right inferior marginmargin

Several other anterior Several other anterior cardiac veins empty cardiac veins empty directly into Right Atriumdirectly into Right Atrium

                                                                  

Problems?Problems?Myocardial Infarction (MI) – Myocardial Infarction (MI) –

Heart Attack.Heart Attack.Blockage to coronary Blockage to coronary

arteries reduces blood flowarteries reduces blood flowDamage to the Left Damage to the Left

Ventricle is the most seriousVentricle is the most serious

Conduction SystemConduction SystemIntrinsic Cardiac Intrinsic Cardiac

Conduction System – Non-Conduction System – Non-contractile cells that contractile cells that initiate and distribute initiate and distribute impulsesimpulses

Conduction SystemConduction SystemSinoatrial Node (SA) – In Sinoatrial Node (SA) – In

right atriaright atriaHeart’s Natural PacemakerHeart’s Natural PacemakerAtrioventricular Node (AV) Atrioventricular Node (AV)

– In interatrial septum – In interatrial septum above tricuspid valveabove tricuspid valve

Conduction SystemConduction SystemAtrioventricular Bundle Atrioventricular Bundle

(bundle of His) – electrical (bundle of His) – electrical connection between atria and connection between atria and ventricleventricle

Bundle Branches – Run down Bundle Branches – Run down interventricular septum to interventricular septum to apexapex

Conduction SystemConduction SystemPurkinje Fibers – Purkinje Fibers – penetrate apex, run penetrate apex, run superiorly up ventricle superiorly up ventricle wallswalls

Like milking a cowLike milking a cow

ECGECGElectrocardiographElectrocardiographWaves includeWaves includeP – SA node sends first P – SA node sends first

impulseimpulse

ECGECGQRS – Ventricular QRS – Ventricular

depolarizationdepolarizationPrecedes ventricular Precedes ventricular

contractioncontractionT – Ventricular T – Ventricular

RepolarizationRepolarization

ECGECGIntervalsIntervalsP-R (P-Q) – Beginning of P-R (P-Q) – Beginning of

atrial excitation and atrial excitation and ventricular contractionventricular contraction

Q-T – Action potential Q-T – Action potential through Heartthrough Heart

Cardiac CycleCardiac CycleSystole – Contraction of Systole – Contraction of

ventricles or atriaventricles or atriaDiastole – Relaxation of Diastole – Relaxation of

ventricles or atriaventricles or atria

Cardiac CycleCardiac CycleSystolic Pressure – Systolic Pressure –

Ventricular contraction Ventricular contraction 120mmHg120mmHg

Diastolic Pressure – Diastolic Pressure – Ventricular refilling 80mmHgVentricular refilling 80mmHg

Hypertension – High BPHypertension – High BPHypotension – Low BPHypotension – Low BP

Heart SoundsHeart SoundsLub-dupLub-dupLub – AV valves close Lub – AV valves close

(systole)(systole)Dup – SL valves close Dup – SL valves close

(diastole)(diastole)

Heart SoundsHeart SoundsMurmurs – obstructions in Murmurs – obstructions in

BVBVThin walled vibrationsThin walled vibrations

Cardiac OutputCardiac OutputCO = amount of blood pumped CO = amount of blood pumped

by each ventricle in 1 minuteby each ventricle in 1 minuteCO = HR x SV (stroke volume)CO = HR x SV (stroke volume)SV = Volume of blood pumped SV = Volume of blood pumped

out by ventricle (Force of out by ventricle (Force of contraction)contraction)

Cardiac OutputCardiac OutputCO = 75 bpm x 70mLpbCO = 75 bpm x 70mLpbCO = 5250 mL/minCO = 5250 mL/min

Developmental Developmental AspectsAspects

Heart pumps by 23Heart pumps by 23rdrd day day1-2 days later, chambers 1-2 days later, chambers

start to formstart to formChambers are:Chambers are:

Developmental Developmental AspectsAspects

Sinus venosus – receives Sinus venosus – receives all venous blood, becomes all venous blood, becomes Rt. Atrium & Coronary Rt. Atrium & Coronary Sinus, SA nodeSinus, SA node

Atrium – becomes muscle Atrium – becomes muscle ridged parts of atriumridged parts of atrium

Developmental Developmental AspectsAspects

Ventricle – Becomes left Ventricle – Becomes left ventricleventricle

Bulbus cordis – Gives rise Bulbus cordis – Gives rise to the pulmonary trunk, to the pulmonary trunk, first part of the aorta, first part of the aorta, most of the right ventriclemost of the right ventricle

Age Related ChangesAge Related ChangesSclerosis – Thickening of Sclerosis – Thickening of

valve flapsvalve flapsDecline in Cardiac Reserve Decline in Cardiac Reserve

– Heart is less able to – Heart is less able to adjust to changesadjust to changes

Age Related ChangesAge Related ChangesFibrosis of cardiac muscle – Fibrosis of cardiac muscle –

Scarred nodes, increase in Scarred nodes, increase in arrhythmiasarrhythmias

Atherosclerosis – acclerated Atherosclerosis – acclerated by inactivity, smoking, by inactivity, smoking, stress. CV diseasestress. CV disease