Open Circulatory System and Closed Circulatory System
There are two types of circulatory system: 1. Open Circulatory System 2. Closed Circulatory System. Here we have discussed difference between open circulatory system and closed circulatory system.
Almost all multicellular organisms need a circulatory system to transport oxygen and nutrients through the body. Evolution has led to the existence of two types of circulatory systems namely:
- Open circulatory system: primarily found in invertebrates. Here, the blood flows freely through cavities since there are no vessels to conduct the blood.
- Closed circulatory system: is found in vertebrates and a few invertebrates like earthworms. This system has vessels that conduct blood throughout the body.
| CHARACTERS | OPEN CIRCULATORY SYSTEM | CLOSED CIRCULATORY SYSTEM |
|---|---|---|
| Occurrence | In some annelids, most of molluscs and arthropods. | In most of annelids, cephalopods,molluscs and all vertebrates. |
| Position of blood | Blood does not remain confined in the blood vessels and comes in lacunae or sinuses. | Blood remains confined in the blood vessels. |
| Blood pressure | Blood flows at low pressure and cannot be regulated. | Blood flows at high pressure and can be regulated. |
| Velocity of blood | Blood flows at a low velocity. | Blood flows at a high velocity. |
| Exchange of materials | Direct exchange between blood and body cells. | Exchange occurs through the tissue fluid |
| Respiratory pigment | When present, it is dissolved in blood plasma. | Always present and is usually present in RBCs e.g. vertebrates. |
| Efficiency | Less efficient as blood takes more time to complete one circulation. | More efficient as blood circulation is completed in short period. |