CARDIOVASCULACARDIOVASCULAR SYSTEMR SYSTEM

Anatomy & Physiology

dr. Jeffrey WiriantaMarch 8th 2004

THE HEART

Lokasi Jantung Lokasi Jantung

Di dalam Pericardium di rongga mediastinum dalam rongga Thorak

Tepat di belakang tulang dada ( sternum )

Kurang lebih 2/3 bagian terletak di sebelah kiri dari garis tengah

Fungsi dan Ukuran

Fungsi : sebagai pompa ganda agar terjadi aliran dalam pembuluh darah yang disebabkan adanya pergantian antara kontraksi ( sistolik ) dan relaksasi ( diastolik )

Ukuran : 250 – 350 gram ( kira-kira sebesar kepalan tangan )

Fibrous SkeletonFibrous Skeleton

Kerangka jantung Kerangka jantung yang terdiri dari yang terdiri dari jaringan kolagen yang jaringan kolagen yang tebal dan kuattebal dan kuat

Penunjang fisik Penunjang fisik jantungjantung

Pegangan katup Pegangan katup Mencegah kelebihan Mencegah kelebihan

regangan otot jantungregangan otot jantung Electrical insulationElectrical insulation

Anatomy of the HeartAnatomy of the Heart

Pericardium : Pericardium : Outer fibrous sackOuter fibrous sack

Myocardium :Myocardium : Thick muscle wallsThick muscle walls

Endocardium : Endocardium : Innermost surfaceInnermost surface EndotheliumEndothelium Simple squamous Simple squamous

epitheliumepithelium

Interventriculer Septum

Papillary muscle

Semilunar Valve

PerikardiumPerikardium

Perikardium Fibrosa Lapisan paling luar rongga Pericardium Menjaga kedudukan jantung di rongga

mediastinum

Perikardium Serosa Lapisan parietalis Lapisan bagian dalam dari rongga pericardial Lapisan visceralis / epicardium

Rongga Perikardium Cairan pericardium Mengurangi gesekan saat jantung bergerak

Anatomy of the HeartAnatomy of the Heart

Heart chambersHeart chambers : : Left & right atriaLeft & right atria Left & right ventriclesLeft & right ventricles

Heart valvesHeart valves : : Atrioventricular valves :Atrioventricular valves :

Right : TricuspidRight : Tricuspid Left : Bicuspid/MitralLeft : Bicuspid/Mitral

Semilunar valvesSemilunar valves Right : Pulmonary valveRight : Pulmonary valve Left : Aortic valveLeft : Aortic valve

Anatomy of the HeartAnatomy of the Heart

AortaAorta Coronary arteriesCoronary arteries ArteriolesArterioles CapillariesCapillaries VenulesVenules Coronary sinusCoronary sinus Right atriumRight atrium

Coronary circulationCoronary circulation

Tipe-tipe sel Otot JantungTipe-tipe sel Otot Jantung

Autoritmik autoritmik – mampu berdepolarisasi spontan produce pacemaker potentials menyalurkan aksi potensial ( impulses )

melewati myocardium tidak berkontraksi

Kontraktil Potensial aksi menimbulkan kontraksi Aliran darah ditimbulkan oleh pergantian dari

kontraksi ( SISTOLIK ) dan Relaksasi ( DIASTOLIK )

Intrinsic Conducting Intrinsic Conducting SystemSystem

Sinoatrial nodeSinoatrial node Electrical pace makerElectrical pace maker

Atrioventricular nodeAtrioventricular node Receives impulses Receives impulses

originating from SA originating from SA nodenode

Bundle of HisBundle of His Electrical link between Electrical link between

atria and ventriclesatria and ventricles Purkinje fibresPurkinje fibres

Distribute impulses to Distribute impulses to ventriclesventricles

Sel AutoritmikSel Autoritmik

• Fase Fase DepolarisasiDepolarisasi

• Fase Fase RepolarisasiRepolarisasi

• Fase IstirahatFase Istirahat

Sel KontraktilSel Kontraktil

• Fase Fase DepolarisasiDepolarisasi

• Fase PlateuFase Plateu

• Fase Fase RepolarisasiRepolarisasi

• Fase IstirahatFase Istirahat

Conduction System

SA Node Internodal branch AV Node Hiss Bundle Purkinje Fiber Contraction

Cardiac Action PotentialsCardiac Action Potentials

Cardiac Muscle TissueCardiac Muscle Tissue

The Electrocardiogram The Electrocardiogram ( ECG )( ECG )

P wave : atrial P wave : atrial depolarisationdepolarisation

QRS complex : QRS complex : ventricular ventricular depolarisationdepolarisation

T wave : T wave : ventricular ventricular repolarisationrepolarisation

Atrial repolarisation Atrial repolarisation hidden by QRShidden by QRS

P

Q

R

S

T

The Electrocardiogram The Electrocardiogram (ECG)(ECG)

Leads can be placed on Leads can be placed on wrists and left ankle wrists and left ankle

( right ankle is ( right ankle is earthed )earthed )

Voltages are measured Voltages are measured across each point as across each point as shownshown I = L wrist to R wristI = L wrist to R wrist II = R wrist to L ankleII = R wrist to L ankle III = L ankle and L wristIII = L ankle and L wrist

The heart sits in the The heart sits in the centre of the trianglecentre of the triangle

I

II III

+/-

+

-

The ElectrocardiogramThe Electrocardiogram

The three standard The three standard measurements can measurements can be used to be used to electronically electronically calculate the calculate the currents flowing currents flowing towards each limbtowards each limb aVRaVR aVLaVL aVFaVF

+

The Cardiac CycleThe Cardiac Cycle

Systole :Systole : Period of ventricular Period of ventricular

contractioncontraction Blood ejected from heartBlood ejected from heart

Diastole Diastole :: Period of ventricular Period of ventricular

relaxationrelaxation Blood fillingBlood filling

Stroke VolumeStroke Volume The amount of blood ejected from the The amount of blood ejected from the

heart in one beatheart in one beat Average is 60 - 100 mlAverage is 60 - 100 ml Depends on preload, contractile force Depends on preload, contractile force

and afterloadand afterload

Cardiac OutputCardiac Output The amount of blood ejected from the The amount of blood ejected from the

heart in one minuteheart in one minute Cardiac output = heart rate x stroke Cardiac output = heart rate x stroke

volumevolume

Starling’s LawStarling’s Law

The more the myocardium is stretched, The more the myocardium is stretched, the greater the stroke volumethe greater the stroke volume

Has limitsHas limits Dependent upon venous returnDependent upon venous return

Blood PressureBlood Pressure BP = cardiac output x systemic BP = cardiac output x systemic

vascular vascular

resistanceresistance

DefinitionsDefinitions

Chronotropy Change in heart rateChronotropy Change in heart rate Inotropy Change in contractile Inotropy Change in contractile

force force Dromotropy Change in conduction Dromotropy Change in conduction

velocity velocity

Can be positive or negative Can be positive or negative