Shape ofheart in rabbit.

Explanation

(i) The heart is pear shaped and lies in the thoracic cavity in between the lungs. It is enclosed b y pericardium, a double layered membrane.

(ii) The , heart is four chambered with two aurides and two ventricles. The right and left auricles are separated by interauricular septum , similarly right and left ventricles are separated by interventricular septum.
(iii) The right auricle opens into the right ventricle by right auriculoventricular aperture , guarded by a trkuspid ,alve.
(iv) The left auricle opens into the left ventricle by left auriculoventricular aperture guarded by a bicuspid valve or mitral vahe.
(v) The opening of the pulmonary artery and aorta are guarded by three semilunar valves.
(vi) The right auricle receives deoxygenated blood through two precaval (superior vena cava) and one postca val (inferior vena cava) veins from all parts of the body.
(vii) The left auricle receives oxygenated blood from the pulmonary veins from the lungs.
(viii) From the right ventricle arises pulmonary trunk which carries the deoxygenated blood to the lungs and from the left ventricle arises the systemic arch (aorta) which supplies oxygenated blood to all parts of the body.