Chambers of Heart15- 12 - 2008

Heart

The heart is a hollow muscular organShape of the heart: pyramid shaped with three surfaces and apex.Surfaces of the heart: sternocostal surface:Formed mainly by the right atrium and the right ventricle diaphragmatic surface:Formed mainly by the right and left ventricle posterior surface (base of the heart):Formed mainly by the left atrium lies opposite the apex Apex: formed by the left ventricle lies at the 5th intercostal space

CHAMBERS and VALVES OF HEART

The heart is divided by the vertical septa into four chambers:-right and left atria-right and left ventriclesValves:- Tricusped valve- ( the cusps give - attachment- to chordae tendinae)- the mitral valve- Aortic valve- Pulmonary valveCardiac muscle:MyocardiumEpicardiumEndocardium

Right atrium

Right Atrium

The RA divided into two parts:

Posterior part called the sinus venarum

Anterior part called atrium proper is rough wall

And appendage called the auricle

Sulcus terminalis:this groove liesOutside of the heart:At the junction between the right atrium and the right auricle is a vertical groove.

Inside the heartThe vertical groove forms a ridge (cristae terminalis)The part lies posterior to the ridge is smooth(derived embryologically from the

sinus venosus)The part in front of the ridge is rough(trabeculated) by muscle ,theMuscle pectinati

Opening into the Right Atrium- superior vena cava:Opens into the upper part of RA(it has no valve)-inferior vena cava:Opens into the lower part of RACoronary sinus:Opens between the inferior vena cava and the atrio ventriclular orificedrains most of the blood from the heart wallAtrioventricular orifice:anterior to the inferior vena cava opening (guarded by tricusped valve)Small orifice of small veinsOpens into the RA

Inter atrial septum,fossa ovalis

A depression seen on the atrial septum

It is oval in shape with a margin called limbus fossa ovalis

In fetus it serves as a communication between right and left atrium

In adult it is closed and appears as a depression called as fossa ovalis

Cavity of right ventricle&semilunar valves

Right ventriclePapillary muscles and valves

Right atrioventricular orffice is guarded by three valves named as tricuspid valve

Tricuspid valves are classified into anterior and posterior and septal based on anatomical position

The margins of the valves attached to chordatendinae which are continuation of the papillary muscle

The largest trabiculae which extends from the interventricular septum to the anterior papillary muscle is called septomarginal trabcula (moderator band)

Trabaculaes are irregular muscular elevation of myocardium which projects into the lumen of both ventricles

Trabaculae carnae,pulmonary valves,papillary muscles&corda tendinae

Pulmonary valves

Pulmonary valves are located at the upper end of the right ventricular

It is placed between R.V and the pulmonary trunk

The orifice is about 3 cm in diameter and is guard by pulmonary valves also called semilunar valves

It has one anterior cusp and two posterior cusp

Left atrium& Left ventricle

Cavity of left ventricle & mitral valve

Left atrium & mitral valve

Left ventricle (mitral and aortic valve)

The inner surface of left ventricle is almost similar features

It has got an inflow tract (left atrioventricular orifice) and outflow tract (aortic orifice)

Trabaculae carneae are irregular muscular ridges The mitral orifice is guarded by two valves

(bicuspid) -one anterior and one posterior the valves attached to the papillary muscle through the chordaetendinae

The outflow tract is guarded by aortic valves (semilunar valves)which leads into the ascending aorta

They are two anterior and one posterior cusp

Arterial supply of the heart

Blood supply of the heart by:Right and left coronary arteries (which arise from the ascending aorta)

Branches of the Right coronary artery:

-Right conus artery-Anterior ventricular branches( gives the marginal branch)-posterior ventricular branchesPosterior interventrcular (descending artery)-The atrial branches

Left coronary artery

Larger than the right coronary arterySupply the major part of the heartBranches:- Anterior interventricular- (descending)- -gives left diagonal artery- and left conus artery- -circumflex artery- gives left marginal artery and- Ant and post ventriclar branches

Venous drainage of heart

Most blood from the heart wall drains into the RA through the coronary sinus (which is a continuation of great cardiac vein).

Great cardiac vein:It open into the RA to the left ofthe inferior vena

cava

Small and middle cardiac vein

Anterior cardiac vein

Nerve supply of the heart

The heart is innervated by:Cardiac plexuses(fibers of autonomic nervous system)Sympathetic fibers (from cervical and upper portion of thorax)Parasympathetic fibers(from the vagus nerve) Situated below the arch of AortaAction of heartCardiac cycle( normal beats 70-90 per minutes for

adult and 130-150 for newborn child)

Fetal Remnants

Fossa ovalis:Is a shallow depression (which is the site of foramen ovale in the

fetus) Anulus ovalis: forms the upper margin of the fossaThese strucures lie on the atrial septum

(which separates the right atrium from the left atrium)

THANK YOUAnd wishing you happy EID

Dr. kumarAssociate professor

Dr. Mashair Abdelrhman