ANATOMY OF THE HEARTANATOMY OF THE HEART

POSITION OF THE HEARTPOSITION OF THE HEART

The muscular pump The muscular pump that is located between that is located between lungs, slightly to the lungs, slightly to the left of the breastbone.left of the breastbone.

SIZE OF HEARTSIZE OF HEART

Slightly larger than a human fist.Slightly larger than a human fist.Weight of between 200 to 425gramsWeight of between 200 to 425gramsHeart is beating approximately 100,000 times Heart is beating approximately 100,000 times everydayeveryday

Anatomy of the heartAnatomy of the heart

Has 4 chambersHas 4 chambersUpper chamber Upper chamber –– called atria ( left and right)called atria ( left and right)Lower chamber Lower chamber –– called ventricle (left and right)called ventricle (left and right)All 4 chambers are separated by wall of muscle All 4 chambers are separated by wall of muscle known as the septumknown as the septum

Chamber of the heartChamber of the heart

Wall of the heartWall of the heart

Pericardium Pericardium –– the outer layer the outer layer –– the thin serous the thin serous membrane comprising the outer surface of the membrane comprising the outer surface of the heart. heart. Myocardium Myocardium –– middle layer middle layer –– muscular wall of the muscular wall of the heart. This thickest middle layer of the heart is heart. This thickest middle layer of the heart is composed of cardiac muscle tissuecomposed of cardiac muscle tissueEndocardiumEndocardium –– inner layer inner layer –– smooth inner surface smooth inner surface of the heart chambers and the valvesof the heart chambers and the valves

RIGHT ATRIUMRIGHT ATRIUM

Receives blood from the body via superior and Receives blood from the body via superior and inferior vena cava.inferior vena cava.Highly distensible chamber Highly distensible chamber -- accommodate the accommodate the VR and maintain a low pressure ( 0 VR and maintain a low pressure ( 0 –– 3 mmHg)3 mmHg)The actual pressure depends upon the volume of The actual pressure depends upon the volume of the blood within the right atrium.the blood within the right atrium.Blood flows down into the right ventricle across Blood flows down into the right ventricle across the tricuspid valve.the tricuspid valve.

Right ventricle (RV)Right ventricle (RV)

Is smaller because it only has to transmit blood Is smaller because it only has to transmit blood a short distance to the lungs.a short distance to the lungs.The free wall is not as thick as the left ventricleThe free wall is not as thick as the left ventricleBlood flow out to the lungs via Blood flow out to the lungs via semilunarsemilunarpulmonicpulmonic valve through the pulmonary arteryvalve through the pulmonary artery

Left atrium (LA)Left atrium (LA)

Blood returns to the heart from the lungs via 4 Blood returns to the heart from the lungs via 4 pulmonary veins that enter the LApulmonary veins that enter the LALA is highly compliant like a RA LA is highly compliant like a RA -- LA pressure LA pressure is higher than RA (6 is higher than RA (6 --10 mmHg)10 mmHg)Blood flows out into the LV across the Blood flows out into the LV across the mitralmitralvalve.valve.

Left Ventricle (LV)Left Ventricle (LV)

Left ventricle (LV) is the largest chamber and Left ventricle (LV) is the largest chamber and has a very thick muscular wall (it can generate has a very thick muscular wall (it can generate high pressures during contraction, as they have high pressures during contraction, as they have to force blood flow through the aortic valve into to force blood flow through the aortic valve into the body)the body)Blood from the LV is ejected across the aortic Blood from the LV is ejected across the aortic valve into the aorta then to the rest of the body valve into the aorta then to the rest of the body and other organs.and other organs.

How does blood travel through the heart?How does blood travel through the heart?

SVCSVC

RARA

RVRV

PULMONARY ARTERYPULMONARY ARTERY

LUNGS ( GAS EXCHANGE)LUNGS ( GAS EXCHANGE)

How does blood travel through the heart?How does blood travel through the heart?

Lungs Lungs

Pulmonary VeinsPulmonary Veins

LALA

LVLV

Aorta Organs Rest of the bodyAorta Organs Rest of the body

Blood flow through the heartBlood flow through the heart

Valves of the heartValves of the heart

Tricuspid valveTricuspid valvePulmonary valvePulmonary valveMitralMitral valvevalveAortic valveAortic valve

Tricuspid valveTricuspid valve

Also called Also called atrioventricularatrioventricular or AV valvesor AV valvesSituated between the RA and RVSituated between the RA and RVHas 3 leaflets with fibrous strands (Has 3 leaflets with fibrous strands (chordaechordaetendineaetendineae) on their leaflets that attach to ) on their leaflets that attach to papillary muscles located on the respective papillary muscles located on the respective ventricular wallsventricular wallsPrevents the backflow of blood from the RVPrevents the backflow of blood from the RV

MitralMitral valvevalve

Also called bicuspid valveAlso called bicuspid valveBetween the LA and LVBetween the LA and LVConsist of 2 leafletsConsist of 2 leafletsPrevents the backflow of blood into LA from Prevents the backflow of blood into LA from the LVthe LV

Pulmonary valvePulmonary valve

Situated between right ventricle and the Situated between right ventricle and the pulmonary artery that leads to the lungspulmonary artery that leads to the lungsHas 3 leafletsHas 3 leafletsIt prevents the backflow of blood into the right It prevents the backflow of blood into the right ventricle from the pulmonary circulationventricle from the pulmonary circulation

Aortic valveAortic valve

Placed between the LV and the aortaPlaced between the LV and the aortaIt consist of 3 It consist of 3 semicicularsemicicular leaflets.leaflets.Prevent backflow of blood from the aorta once Prevent backflow of blood from the aorta once it has left the heartit has left the heart

The papillary muscles contract during The papillary muscles contract during ventricular contraction and generate tension ventricular contraction and generate tension

on the valve leaflets via the on the valve leaflets via the chordaechordae tendineaetendineaeto prevent the AV valves from bulging back to prevent the AV valves from bulging back into the atria and becoming incompetentinto the atria and becoming incompetent

Blood supply to the heartBlood supply to the heart

Heart muscle needs more oxygen than any organ Heart muscle needs more oxygen than any organ except the brain , therefore the heart must have except the brain , therefore the heart must have generous supply of bloodgenerous supply of bloodThe flow of blood that supplies the heart tissue The flow of blood that supplies the heart tissue itself is the coronary circulationitself is the coronary circulationBlood is supplied to the heart by coronary artery Blood is supplied to the heart by coronary artery –– left and rightleft and right

Coronary arteryCoronary artery

Right coronary arteryRight coronary artery

Right marginal branch Right marginal branch –– supply blood to the lateral wall of the RVsupply blood to the lateral wall of the RVPosterior Posterior interventricularinterventricular artery artery ---- within the posterior within the posterior interventricularinterventricular sulcussulcus . .

–– supply blood to the ventricles supply blood to the ventricles posteriorlyposteriorlyIt also supply blood It also supply blood -- 55% to SA node55% to SA node

-- 90% to AV node90% to AV node-- a portion of Bundle of Hisa portion of Bundle of His

Left coronary arteryLeft coronary arteryBegins behind the left cusp of the aortic Begins behind the left cusp of the aortic semilunarsemilunar valve and valve and devidedevide into 2 branchinto 2 branch

1 1 –– anterior anterior interventricularinterventricular branch which branch which decendsdecends in the anterior in the anterior interventricularinterventricular sulcussulcus ( ( LAD).LAD).---- supply blood to the ventricles supply blood to the ventricles anteriorlyanteriorly

2 2 –– a circumflex branch which a circumflex branch which continouscontinous in the in the coronary coronary sulcussulcus ((LCxLCx ))

---- supply blood to most of the posterior wall of supply blood to most of the posterior wall of the heartthe heart

Left Anterior DescendingLeft Anterior Descending

Supply blood to :Supply blood to :Anterior 2/3 of septumAnterior 2/3 of septumRight bundle branch Right bundle branch AnterosuperiorAnterosuperior division of the left bundledivision of the left bundleAnterior wall of the left ventricleAnterior wall of the left ventricle

Left circumflex Left circumflex

SA node (45%)SA node (45%)PosteroinferiorPosteroinferior division of left bundle ( a division of left bundle ( a portion)portion)Lateral wall of the LVLateral wall of the LV

Conduction system of the heartConduction system of the heart

Consist of modified Consist of modified cardiac muscle cellscardiac muscle cells

2 nodes that play 2 nodes that play fundamental parts in fundamental parts in this conduction this conduction systemsystem

Conduction systemConduction system

Sino Sino –– atrialatrial (SA) node(SA) node–– located in the posterior wall of right atrium located in the posterior wall of right atrium –– also known as the pacemakeralso known as the pacemaker---- a stimulus arising from the a stimulus arising from the SAnodeSAnode cause cause atrialatrialto contractto contract

( impulse from SA node travel to the AV node)( impulse from SA node travel to the AV node)

Conduction systemConduction system

AtrioventricularAtrioventricular (AV ) node(AV ) node---- found in the inferior part of the found in the inferior part of the interatrialinteratrialseptum.septum.

---- It acts as a relay stationIt acts as a relay station

Conduction systemConduction system

Then impulse passes through bundle of His ( Then impulse passes through bundle of His ( atrioventricularatrioventricular bundle) , it is located in the bundle) , it is located in the interventricularinterventricular septum and septum and devidesdevides to form the right to form the right and left bundle branches.and left bundle branches.Impulse then generate through Purkinje Impulse then generate through Purkinje fibresfibres which which form the branching of right and left bundle branches at form the branching of right and left bundle branches at the apex of the heart.the apex of the heart.Its function is to stimulate the ventricles to contractIts function is to stimulate the ventricles to contract

Conduction system of the heartConduction system of the heart

Thank youThank you