The circulatory system of Channa Punctatus comprises of:
(i) The circulatory fluid—the blood,
(ii) The pumping organ—the heart,
(iii) The arteries and
ADVERTISEMENTS:
(iv) The veins.
(i) Blood:
Blood is a pale-coloured fluid. It contains elliptical, nucleated erythrocytes and amoeboid leucocytes suspended in the plasma.
(ii) Heart:
ADVERTISEMENTS:
Heart is located ventral to the oesophagus in the pericardial section of the coelom. It is enclosed within a thin pericardium. It is constructed by two types of chambers:
(a) Receiving chambers:
The sinus venosus and the auricle constitute the receiving parts of the heart. The sinus venosus is a dorsally placed thin-walled sac. It receives deoxygenated blood by two caval veins or ductus Cuveiri. The auricle is a single thin walled chamber and is situated ventral to the sinus venosus. The sinus venosus opens to the auricle by a Sino auricular aperture which is guarded by valve.
The auricle opens into the ventricle by auriculoventricular aperture. This aperture is guarded by valves. Through both these aforesaid apertures the blood flows in the direction from sinus venosus to auricle and from auricle to the ventricle, respectively. The valves guarding the apertures prevent the change of direction or back-flow of blood and thus maintain a unidirectional flow of blood through the different parts of the heart.
ADVERTISEMENTS:
(b) Forwarding chamber: <