Human Anatomy Vol 1

PERICARDIUM AND HEART

Arch of aorta

Pulmonary trunk

Left Atrium

Anterior cusp of left AV opening

Chordae tendinae

Circumflex branch of left coronary

artery and great cardiac vein

Anterior papillary muscle

4 There are two well-developed papillary muscles,
anterior and posterior. Chordae tendinae from both
muscles are attached to both the cusps of the mitral
valve.
5 The cavity of the left ventricle is circular in cross-
section (Fig. 18.15).
6 The walls of the left ventricle are three times thicker
than those of the right ventricle.
Table 18.3 compares the right ventricle and the left
ventricle.

ultimately the rising back pressure causes right

sided failure (congestive cardiac failure or CCF)

which is associated with increased venous

pressure, oedema on feet, and breathlessness on

exertion. Heart failure (right sided) due to lung

disease is known as cor pulmonale.

. The area of the chest wall overlying the heart is
called tii.e precordium.

LVES

The valves of the heart maintain unidirectional flow of

the blood and prevent its regurgitation in the opposite

direction. There are two pairs of valves in the heart, a

pair of atrioventricular valves and a pair of semilunar

valves. The right atrioventricular valve is known as the

tricuspid valve because it has three cusps. The left

atrioventricular valve is known as the bicuspid valve

because it has two cusps. It is also called the mitral

valve. The semilunar valves include the aortic and

pulmonary valves, each having three semilunar cusps.

The cusps are folds of endocardium, strengthened by

an intervening layer of fibrous tissue (Fig. 18.17).

Atrioventriculor Volves

L Both valves are made up of the following com-

ponents.

a. A fibrous ring to which the cusps are attached

(Fig. 18.13).

b. The cusps are flat and project into the ventricular

cavity. Each cusp has an attached and a free

Rapid pulse or increased heart rate is called

tachycardia (Greek rapid heart).

Slow pulse or decreased heart rate is called

bradycardia (Greek slow heart).

Irregular pulse or irregular heart rate is called

arrhythmia.

o Consciousness of one's heartbeat is called

palpitation.

o Inflammation of the heart can involve more than

one layer of the heart. Inflammation of the

pericardium is called pericarditis; of the myo-

cardium is myocarditis; and of the endocardium is

endocarditis.

. Normally the diastolic pressure in ventricles is
zero. Apositive diastolic pressure in the ventricle
is evidence of its failure. Any one of the four
chambers of the heart can fail separately, but

Fig" 18.16: lnterior of left atrium and left ventricle