It includes blood, heart and blood vessels
(A) Blood :
The blood is red and made up of plasma (60%) & blood corpuscles (40%). The blood corpuscles are of three types viz. –
- Red blood corpuscles : They contain hemoglobin.
- White blood corpuscles
- Thrombocytes.
(B) Heart :
It is a triangular (cone-shaped), dark red in color and muscular structures. It is situated in the anterior part of body cavity at the level of fore limbs. It consists of two anterior auricles (left and right) and one posterior ventricle. Both the auricles open into the ventricle through a common auriculo-ventricular aperture.
There is a triagular sinus venosus which receives two precavals and one post caval. The sinus venous opens into the right auricle. There is truncus arteriosus on the right ventral side of the heart. The ventricle opens into the truncus arteriosus. The left auricle receives pulmonary veins.
(C) Blood Vessels ;
In includes arterial system (various types of arteries) and venous system (various types of veins). The veins form
two types of portal systems viz. –
- Hepatic portal system – In liver
- Renal portal system – In kidneys
