heart has two ventricles, which includes a right and a left
The right ventricle receives blood from the right atrium during
ventricular diastole and propels blood into the pulmonary circulation
during ventricular systole (figures 104a, 105a, 105b). The right
ventricle is normally the most anterior cardiac chamber, lying
directly beneath the sternum. The right ventricle is partially
below, in front of, and medial to the right atrium but anterior
and to the right of the left ventricle. The striking difference
in configuration between the two ventricles illustrated by a
transverse section (figures 104a, 105a).
The left ventricular chamber is an ellipsoidal sphere surrounded
by thick musculature, well suited to ejecting blood against
the high resistance of systemic vessels.
The right ventricle (RV), which normally contracts against very
low resistance, has a crescent- shaped chamber and a thin outer
wall. The anterior and inferior walls of RV cavity are lined
by muscle bundles (trabeculae carneae). There is also a rather
constant muscle, the moderator band, which crosses from the
lower ventricular septum to the anterior wall, joining the anterior
papillary muscle. The right bundle courses through the moderater
band to reach the endocardium.
left ventricle (LV) (figures 104b, 105a, 105b) receives blood
from the left atrium during ventricular diastole and ejects
blood into the systemic circulation during ventricular systole.
The LV is bullet shaped with a blunt tip directed anteriorly,
inferiorly, and to the left, where it contributes to,with the
lower ventricular septum,to the apex of the heart. The major
portion of its external surface is posteriolateral.The LV is
posterior and to the left of the RV and inferior, anterior,
and to the left of the left atrium. The LV chamber is an ellipsoidal
sphere,surrounded by thick muscular walls,about three times
the thickness of the RV wall. The ventricular septum is the
medial wall of the LV. The lower 2/3 of the LV is ridged with
by interlacing muscles, the trabeculae carneae.