THE HEART
Cardiovascular system 
THE HEART
It is a conical hollow muscular pump inside
the pericardium occupying a major part in
the chest.
It is formed of four chambers two atria (right
and left) and two ventricles (right and left).
THE HEART
The heart has an
apex, base and two
surfaces.
 The surfaces are
the sternocostal
and diaphragmatic.
 The borders are
right, left, upper
and lower borders.
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THE HEART
Apex
 It is formed only by the
left ventricle.
 It is directed
downwards, forwards
and to the left.
 It lies below nipple of
the left breast, in the
left 5th intercostal
space.
THE HEART
Apex
It lies below nipple of the left breast, in the
left 5th intercostal space.
THE HEART
Base
It is formed mainly by
the left atrium and
the back of the right
atrium.
It is directed
backwards and to
the right.
THE HEART
Sternocostal surface
 It is directed
forwards, upwards
and to the left.
 It is divided by the
coronary groove into
arterial portion and
ventricular portion.
THE HEART
Sternocostal surface
 Arterial portion: mainly
the right auricle and a
small part of the left
atrium form it.
 Ventricular portion: One
third of this surface is
formed by left ventricle,
and two thirds by the
right ventricle.
THE HEART
Diaphragmatic surface
It is directed downwards
and slightly backwards.
It is formed by the two
ventricles.
Two thirds by the left
ventricle and one third
by the right ventricle.
THE HEART
Borders
Upper border is formed by the
two atria, mainly the left.
Right border is formed only by
the right atrium.
Lower border is formed by the
right ventricle and the
apical part of left ventricle.
Left border is formed mainly
by the left ventricle and
partly by the left atrium.
Chambers of the heart
There are 4 chambers of the heart
Right atrium
Left atrium
Right ventricle
Left ventricle
THE HEART
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Right atrium
It is separated from
the left atrium by the
inter-atrial septum.
The right atrium is
composed of two
main parts, a smooth
posterior portion and
a rough walled
anterior portion.
The rough portion
contains the
pectinate muscles.
THE HEART
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Left atrium
The left atrium forms
the greater part of the
base of the heart.
The left auricle lies to
the left and in front of
the pulmonary trunk.
THE HEART
Left atrium
 Its interior presents a
smooth surface excepts
for view rough part.
 The left atrium shows the
following orifices:
1. Four Pulmonary veins
convey blood from lungs
to the heart.
2. Mitral valve: It connects
the left atrium with the
left ventricle. Two cusps
guard it.
THE HEART
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Right ventricle
Separated from left ventricle by interventricular
septum.
Its wall is muscular &is more thicker than the atrial.
Pulmonary trunk arises from it and divides into two
pulmonary arteries one to each lung.
THE HEART
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Right ventricle
There are three papillary
muscles attached to the
wall of the ventricle.
Form the apices of the
papillary muscles, fibrous
cords (chorda tendinae)
pass to the cusps of the
tricuspid valve.
THE HEART
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Right ventricle
There are three papillary muscles attached to the
wall of the ventricle.
Form the apices of the papillary muscles, fibrous
cords (chorda tendinae) pass to the cusps of the
tricuspid valve.
THE HEART
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Left ventricle
It forms the apex
of the heart.
Its wall is nearly
three times thicker
than right.
The ascending
aorta arises from
it.
THE HEART
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Left ventricle
Its cavity presents two papillary muscles, which
are attached to the two cusps of the mitral valve
by chorda tendinae.
Valves of the heart
Tricuspid valve – It is valve between right
atrium and right ventricle
Bicuspid valve ( Mitral valve ) – It is
valve between left atrium and left ventricle
Pulmonary valve – It is the valve between
pulmonary trunk and right ventricle
Aortic valve – It is the valve between
aorta and left ventricle
Valves of heart
THE HEART
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Pericardium
The pericardium is the serous
sac, which invests the heart.
It consists of an outer fibrous
sac lined with an inner serous
sac.
The heart lies inside the fibrous
sac and invaginates the serous
sac from behind.
So the serous pericardium has
a visceral layer covering the
heart and a parietal layer lining
the fibrous pericardium. The
fibrous pericardium limits
movements of the heart.
THE HEART
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Arterial supply
Two coronary arteries arise from
the aortic sinuses in the initial
portion of the ascending aorta and
supply the muscle and other
tissues of the heart.
They circle the heart in the
coronary sulcus, with marginal
and interventricular branches, in
the interventricular sulci,
converging toward the apex of the
heart.
They are end and tortuous
arteries.
THE HEART
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Venous drainage
The returning venous blood passes
through cardiac veins, most of
which empty into the coronary
sinus.
This large venous structure is
located in the coronary sulcus on
the posterior surface of the heart
between the left atrium and left
ventricle. The coronary sinus
empties into the right atrium
between the opening of the inferior
vena cava and the right
atrioventricular orifice.
THE HEART
Arterial supply