Vascular
Biology,
Structure and Function
15
closely associated with the pumping action
of
the left ventricle. The
ventricle also contracts much more in the short-axis or circumferential
direction than the long-axis or base-to-apex direction. The ventricles are
made up
of
muscular fibers. This so-called "myocardium" can be further
divided
transmurally
into the inner endocardium
and the
outer
epicardium.
rRY
Fig.
2.1.1
:
Diagram illustrating the overall circulation. The four cardiac chambers
(LV
=
left ventricle,
LA
=
left atrium,
RV
=
right ventricle,
RA
=
right atrium) and systemic and
pulmonary circulations
are
shown. Arrows indicate directions
of
blood flow.
