Circulatory system can be classified into two types:
- closed circulatory system
- open circulatory system
Closed Circulatory System
- Usually found in large animals such as vertebrates.
- Medium of transport is blood
- The blood flows continuously in blood vessels
- Exchange of gases, nutrients and waste products occurs between the blood in the capillary and the body cell.
Open Circulatory System
- Usually found in smaller animals such as insects and shellfish.
- Medium of transport is haemolymph.
- Haemolymph is pumped from the heart into the cavity around the body cells.
- Exchange of nutrients and waste products occurs directly between and the body cells the blood around it.
- The haemolymph is then pumped back to the heart.
Close Circulatory System vs Open Circulatory System
|Open Circulatory System||Close Circulatory System|
|Occurrence||Small animals such as insects||Large animals such as vertebrate|
|Control of fluid flow||Low level of control||High level of control|
|Presence of valve||No||Yes|
|Pressure of circulating fluid||Relatively low||Relatively high|