Agriculture Reference
In-Depth Information
Figure 6.21
External confi guration of the heart: A. Left (auricular) side; B. Right (atrial) side.
described with the digestive system, because of its topo-
graphic relations to the stomach.
The atria end in the auriculae (sing. auricula), on both
sides of the origin of the pulmonary trunk. The atria are
visible on the right side of the heart, whereas the auriculae
are on the left side of the heart. The two ventricles are
separated from each other by two vertical grooves that
protect arteries and veins nourishing the heart. The two
aspects of the heart and the major vessels are illustrated in
Figure 6.21 .
The Heart
As an aspiro-repellent pump receiving and pumping blood
into the body, the heart is a muscular organ protected
within the thoracic cavity. It is intimately surrounded by a
double layer pericardium, and is located between the two
lungs. From the outside, one can estimate the position of
the heart between the ribs III and VI.
I
NTERNAL
C
ONFIGURATION
The right atrium communicates with the right ventricle,
whereas the left atrium communicates with the left ven-
tricle. The communications are provided with atrio-
ventricular (AV) valves, complex structures allowing the
blood to pass from the atria to the ventricles, but not back
to the atria. They consist of three (for the right AV valve)
and two (for the left AV valve) leafl ets anchored to strong
papillary muscles by tendinous cords. The pulmonary arte-
rial trunk originates from the right ventricle, while the
aorta originates from the left ventricle. Both are provided
E
XTERNAL
C
ONFIGURATION
The heart has a base oriented dorsally and a tip oriented
ventrally. The base consists of two atria (sing. atrium),
right and left, on top of two ventricles, right and left. The
base is associated with the great vessels of the heart and is
much smaller than the ventricles. The atria are separated
from the ventricles by a horizontal groove called the coro-
nary groove, which protects the coronary arteries and the
great cardiac vein.
