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located in the coronary sulcus on the posterior surface of the
heart.
It has the following vessels:
● v. cordis magna which begins on the anterior surface of
the heart and goes along anterior interventricular septum;
● v. cordis media is located in the posterior interventricular
sulcus;
● v. cordis parva is located in
the right part of coronary
artery;
● v. posterior ventriculi sinistri is located on the posterior
wall of left ventricle;
● v. obliqua atrii sinistri is located on the wall of left
pulmonary atrium.
The smallest cardiac veins or Thebesius – Vieussens veins
(vv. cardis minimae) in the amount of 20 – 30 small vessels go
to the right heart cavity. In cardiac strain (respiratory
insufficiency) these vessels drain blood to the right pulmonary
atrium.
Heart innervation
is provided by branches of cervical and
thoracic segments of sympathetic trunk and also by branches
of vagus nerves (parasympathetic innervation).
They form
plexus cardiacus on aorta and pulmonary trunk, the branches
of which go to the cardiac muscle.
There are many parasympathetic fibres in the ascending part
of aorta and pulmonary trunk which are the part of vagus nerves
and recurrent laryngeal nerves. Parasympathetic nervous fibres
slow down cardiac rhythm and narrow coronary arteries. That is
why during the treatment of patients who suffer coronary heart
disease plexotomia and coronary artery bypass graft are
performed. Plexotomia or cutting of antenodal parasympathetic
nervous fibres eliminates coronary arteries spasm. On the other
hand cutting of antenodal parasympathetic nervous fibres
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eliminates pain syndrome.
Cardiac conduction system
plays an important role in
phisiology and pathology.
Сardiac conduction system (complexus stimulans cordis,
s. systema conducente cordis) consists of Keith – Flack node,
Aschoff – Tawara node, His bundle which branches in to right
and left foot.
Keith – Flack node (nodus sinuatrialis) is atypical
cardiomyocytes which are located under the epicardium on
anterior surface of right atrium in the place of its merging with
v. precava. Its cells are grouped around the central artery of
Keith – Flack node. Keith – Flack node is the pacemaker and
the source of cardiac automatism, the place of cardiac impulse
formation.
Aschoff – Tawara node (nodus atrioventricularis) is located
under endocardium of right atrium in its inferior-anterior
segment. The node goes into the right fibrous triangle which is
located in
the place of right tricuspid, bicuspid and aortic
valves junction and then it goes into atrioventricular bundle.
Atrioventricular bundle goes through membrane of
interventricular septum and branches into left and right foot.
A slow rhythm of heart rate (less than 40 beats/min)
causes anemia, vertigo and loss of consciousness.
In ineffecient treatment of this condition with
antiarrhythmic agents the surgical treatment is prescribed. It is
implantation of cardiac pacemaker. It is sewed under
hypodermic tissue of infraclavicular part. Electrodes are
conducted through the subclavian vein into the right ventricle.
From the congenital heart defects ductus arteriosus is mostly
observed. It is a vessel through which the pathological
conjunction of aorta and pulmonary trunk is observed after birth.
The arterial canal branches off from the aortic arch at the
left subclavian artery and goes obliquely up and down
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entering the branching of the pulmonary trunk branching.
Mediastinal pleura covers the arterial canal anteriorly. There
are two nerves passing anteriorly to ductus arteriosus: vagus
nerve and phrenic nerve. The recurrent laryngeal nerve rounds
it behind, goes up and passes between
the posterior wall of
arterial canal and left main bronchus.
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