Download Slide 1

In the name of
GOD
ANATOMY AND PHYSIOLOGY OF THE HEART
By Dr A.R Hoghooghi
GROSS ANATOMY
• Heart composed of 4 chamber ,2 atria 2 ventricle
form 2 separete pump arranged side by side and
in serie.
• atria low pressure ,capacitance chamber store
blood during systole and fill vent during diastole 2
atria separate with thin IAS
• Ventricles are high pressure ,pumping blood to
lung and peripheral .LV IS THICKER. Separet with
IVS memberanous in sup and thick muscular in
medial and distal
Mitral valave and tricuspid
• Separate atrioventricular valaves
• Chorda tendinea attach valaves to papillary
muscles
• Papillary muscle extension of normal
myocardium
• Seminular valves AOV and PV do not have
chorda fibrous valves
• Each valves has fibrous ring or annulus
Pericardium
• Double layered ,surround heart
• Visceral pericardium is adherent to heart
• Parietal attaches to sternum ,vertebral column
,diaphragm serves to to stabilize heart
• Pericardium has 50 ml fluid which is normal
• Pericardial fluid lubricate contact surface and
modulates interventricular interaction
CIRCULATORY PATHWAY
• 2 DISTINCT PARALLEL VASCULAR NETWORK
• ARTERIAL VENOUS DEOXYGENATED BLOOD
FROM TISSUES DRAIN FROM SUP AND INF VENA
CAVA TO RIGHT ATRIUM
• BLOOD FROM HEART DRAINS FROM COROARY
SINUS TO RIGHT ATRIUM
• OXYGENATED BLOOD DRAINS FROM LUNGS TO
PULMONARY VEIN (4)
• HEART RECIEVES BLOOD FROM RIGHT AND LEFT
CORONARY ARTERIES
CORONARY ARTERIES
• They are first braches of aorta
• Originating from sinuses of valsalva
• Left main coronary arteries originates in left sinus
of valsalva which biforcate to 2 vessel left
circumflex(lcx) and (LAD)
• LAD travel anterior interventricular groove
toward apex
• LAD suplies blood for ant and anterolat LV by
septal branches through its DIAGONAL branches
and to ant of 2/3 intventricular septum
LCX
• TRAVELES POSTERIORLY IN THE LEFT
AVGROOVE ,suplies blood for lat LV through
optus marginal branches and also LA
RCA
• RCA is originate from right sinus of valsalva
• Courses down the right AV groove to a point wher the
left and right AV groove and inferior interventicular
groove meet,the crux of the heart
• Gives off atrial branch and acute marginalis branches
for RV
• In 85% RCA biforcate at crux to pda travels
infinterventricular groove to supply blood to the inf lv
wall and inf 1/3 of interventricular septum and plv
supply blood for post lvwhich is right dominant.10%
left dominant and PDA PLV from lcx,5%codominant
RCA gives PDA and LCX gives PLV
COLLATERALS
• Nonfunctional in normal heart because no
pressure gradient developes accros them
• Developing of collaterals is directly dependet
to severity coronary stenosis ,can reach to
1mm diameter
Conduction system
• SA node, pacemaker cells ,1 to 2 cm diameter
,located high in RA between SVC RA appendag
,supply by sa nodal artery 60% from RCA and
40% from LCX
• AV node located in at inferior aspect of RA
between coronary sinus and septal leaflet of
tricuspid valveprovide normal
electricalconnection between atria ventricles
,Avnodal branch 90% RCA 10% lcx
• Bundle of His extend from av to membrabous IVS to
muscular part of IVS SEPARATE TO 2 BRANCHES
• RIGHT BUNDLE is disceret branch extend along IVS
enter moderator band and to anterolateral papillary
muscle of RV,blood from septal perforator lad
• LBB IS LESS DISTINCT ant fascicle to anterolat papilary
muscle and post fascicle to posterolatral papillary
muscle of lv ,blood for ant fascicle by septal perforator
lad, susceptable to ischemia,blood for post (proximal
from av node artery and septal and distal from lad and
pda
Neural innervation
• Sympathic preganglionic neurons located within
sup five to six thoracic segment
• These fibers end in the SA node AV node
,epicardial vessel and myocardium
• Parasympathetic from preganglionic neurons
originating in the dorsal motor nucleus of the
medulla and pass as a branch fo vagus nerve to
heart
• Supply of vagal afferent from the inferior and
posterior aspects of the ventricle mediate cardiac
reflexes
Circulatory physiology and the cardiac
cycle
• During the course of one cardiac cycle ,the electrical event initiate
and therefore precede the mechanical (pressure )events ,and the
latter precedes the ausculatory events (heart sounds)they
themselvesw produce.shortly after the p wave the atria contract to
produce a wave .the QRS complex initiate ventricular systole
,followed shortly by lv contraction and rapid buildup of LV pressure
.lv pressure exceeds LA pressure ,closing the mitral valave and
producing the first heart sound after a period of isovolumic
contraction ,lv pressure exceeds aortic pressure and AV
OPENSwhen the ventricular pressure once again falls below the
aortic pressure ,and the aortic valve close to produce the second
heart sound and terminate ventricular ejection .the lv pressure
decreasee during the period of isovolumic relaxation until it drops
below LA
pressure ,and the mitral valve opens
Cardiac performance
• The amopunt of blood ejected by the each
minute is refered to as the cardiac output is
the product of stoke volume and HR
• CARDIAC INDEX :co divided by BSA
• NORMAL CO:4 TO 6 LIT /MIN can increase
during exercise 4 to 6 fold as a result of hr
chronotropy or sv inotropy
• Sv is a measure of mechanical function of the heart and is
affected by preload afterload and contractility
• Preload is the volume of blood in the ventricle at the end of
diastole and is primarily a reflection of venous return
,(ventricular filling pressure, atrial pressure or pcwp)used
as a surrogate measure of preload
• Afterload is the force against which the ventricle must
contract to eject blood.the arteria pressure as a practical
measure of after load ,as atruth the interventricular
pressure the size of vent cavity and thickness of ventricular
wall (laplace s law)determine after load so in hypertension
stenosis and lvh and lv dilation is increased afterload
Ejection fraction
• Overall ventricular systolic function is frequently
quantified by the ejection fraction
• Which is the ratio of the sv to the end diastolic
volume that is fraction of blood in the ventricle
ejected with each ventricular contraction
• Normal ef is about 60%
• Ventricular diastolic function (lusitropy)also plays
an important role in over all cardiac performance
• Myocardial oxygen consumption mvo2 the
main determinant are HR contractility and
wall stress which is determined by laplace law
=(pressure*radius)/(2*wall thickness)
• Most coronary flow occurs during diastole
therefore diastolic pressure is the major
pressure driving the coronary circulation