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Cardiovascular system
HEART
• The heart has four chambers: right
and left atria and right and left
ventricles.
Borders and surfaces
Anterior
surface of
heart
Superior vena cava
Aorta
Pulmonary trunk
Anterior
interventricular
sulcus
Right
atrium
Right
ventricle
Atrioventricular
sulcus
Inferior vena cava
Left ventricle
The apex of the heart
• Is formed by the inferolateral part of the left
ventricle.
• Lies posterior to the left 5th intercostal space
in adults, usually approximately 9 cm (a hand's
breadth) from the median plane.
• Anterior (sternocostal) surface,
formed mainly by the right ventricle.
• Right pulmonary surface,
formed mainly by the right atrium.
• Left pulmonary surface,
formed mainly by the left ventricle.
Posterior
surface of
heart
Aorta
Left pulmonary
veins
Superior vena cava
Pulmonary
trunk
Left
Atrium
Atrioventricular
sulcus
Left
ventricle
Right
Pulmonary
veins
Right
atrium
Inferior vena
cava
Right ventricle
Borders of the heart
• Right border
formed by the right atrium and extending
between the SVC and the IVC.
• Inferior border
formed mainly by the right ventricle and
slightly by the left ventricle.
• Left border
formed mainly by the left ventricle and slightly
by the left auricle.
• Superior border,
formed by the right and left atria and auricles
in an anterior view ;
Right atrium
1-
234-
It is separated from the left atrium by the interatrial septum.
The right atrium is composed of two main parts, a smooth
posterior portion and a rough walled anterior portion. The
large smooth part presents the following orifices :
The inferior vena cava: Opens into the lower posterior part. It
brings blood from the lower limbs and abdomen to the right
atrium.
The superior vena cava: Opens into the upper posterior part.
It brings blood from head, neck, upper limbs and thorax.
Tricuspid valve: It connects the right atrium with the right
ventricle. It is guarded by three cups.
The coronary sinus: It conveys venous blood from the heart
wall to the right atrium.
Left atrium
The left atrium forms the greater part
of the base of the heart. It wall presents a
smooth surface except for a small rough part
(the left auricle) which lies to the left and in
front of the pulmonary trunk. The left atrium
shows the following orifices:
1- The four pulmonary veins two from each
lung.
2- The mitral valve connects the left atrium
with the left ventricle
Right ventricle
It is separated from the left ventricle by
interventricular septum. Its wall is muscular
and is thicker than the atrial wall. The
pulmonary trunk arises from the right
ventricle and divides into two pulmonary
arteries one to each lung. There are three
papillary muscles attached to the wall of the
ventricle. From the apices of the papillary
muscles, fibrous cords (chorda tendinae)
pass to the cusps of the tricuspid valve.
Left ventricle:
The left ventricle is longer than the right
ventricle and forms the apex of the heart. Its
wall is nearly three times thicker than the right.
The ascending aorta arises from it. Its cavity
presents two papillary muscles which are
attached to the two cusps of the mitral valve by
chorda tendinae.
circulation
• Conducting system of the heart:
•
The conducting system of the heart
consists of modified cardiac muscle fibers
which are responsible for initiation and
maintenance of cardiac rhythm. The
conducting system is formed of:
• 1- Sino-atrial node (SAN).
• 2- Atrioventricular node (AVN).
• 3- Atrioventricular bundle (AVB).
• The aorta and its main branches :
•  The ascending aorta arises from the left ventricle.
It gives two coronary arteries, right and left. The
coronary arteries supply the heart.
•  Ascending aorta arches to give the aortic arch.
The aortic arch gives 3 arteries:
1-Brachiocephalic artery which gives the right
subclavian and right common carotid arteries.
2-Left common carotid artery. 3-Left subclavian artery.