Physiology of Finfish and Shellfish (2+1)

2.2.4. Major differences between closed and open circulation system

Sl.No.	Closed systems	Open systems
1.	Usually high pressure systems	Usually low pressure systems
2.	Blood conveyed directly to organs	Similar to closed systems
3.	Distribution to different organs can be regulated	Distribution of blood not ready regulated
4.	Blood returns to hearts rapid	Blood returns to heart slow

1. Constriction in a tube curves along the tube pushes blood ahead of it. illustration
2. Rhythmical constructions of the walls forec blood out. Valves prevent bake flow and the blood is therefore expelled in one direction only.
3. Blood is rushedout of a couapsible tries by pressing from surrounding tissues. Coutracting muscles provide the pressure and values prevent back flow.