Difference Between Open Circulatory System vs. Closed Circulatory System

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Main Difference

The circulatory system in an organism is responsible for the transportation of blood, useful nutrients and the supply of oxygen to different parts of the body. The more the complex organism, the more the complex circulatory system it has. For example, the circulatory system in Human is more complex than the circulatory system in the insects. The developed circulatory system comprises of the specialized circulatory fluid, heart, blood and blood vessels; they all take part in the pumping of blood to the tissues. On the basis of the blood vascular system, there are two types of the circulatory or the vascular system. The open circulatory system is present in the invertebrates like molluscs and arthropods. In the open circulatory system, the blood pumped by the heart is filled in the body cavities (Haemocoel). On the other hand, the closed circulatory system is present in the invertebrates like earthworms and cephalopods. In the closed circulatory system, the blood pumped by the heart is transported to the other parts through the vessels and the haemocoel is absent in this case.

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Comparison Chart

Open Circulatory SystemClosed Circulatory System
Blood FlowThe blood flow in the open circulatory system takes place through the vacant spaces called sinuses and lacunae.The closed vessels are present in the closed type of circulatory system and they are held responsible for the blood flow.
HaemocoelIn open circulatory system, when the blood gets pumped by the heart, it gets stored in the cavity called Haemocoel.Absent
Rate of Blood SupplyBlood transportation requires more time and the rate of supply and elimination of material is also quite low.Blood transportation requires less time and the rate of supply and elimination of material is also fast.
ExampleThe open circulatory system is present in the invertebrates like molluscs and arthropods.The closed circulatory system is present in the invertebrates like earthworms and cephalopods.
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What is Open Circulatory System?

The open circulatory system is a less-efficient vascular system, which is present in the invertebrates like molluscs and arthropods. In this circulatory system, the blood transportation requires more time and the rate of supply and elimination of material is also quite low as compared to the closed circulatory system. The blood flow in this type of vascular system takes place through the vacant spaces called sinuses and lacunae. When the blood gets pumped by the heart, it gets stored in the cavity called Haemocoel. Even the internal organs of that organism in the open circulatory system get bathed in blood. As the supply and exchange of the material is the other important function of the circulatory system; in this circulatory system the exchange of material happens in between the blood and sinuses. The blood flow velocity is even slower in this type of the circular system, and the blood flow can’t be regulated in this type of system.

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What is Closed Circulatory System?

The closed circulatory system is a more efficient vascular system, which is present in the invertebrates like earthworms and cephalopods. In this circulatory system, the blood transportation occurs rapidly and at the same time the supply and elimination of materials are also rapid. The closed vessels are present in this type of circulatory system and they are held responsible for the blood flow. Unlike, open circulatory system, in this system the cavity where blood is stored (Haemocoel) is absent. As the vessels work in the transportation of blood, the internal organs do not remain in direct contact with the blood. The exchange and elimination of material take place through the capillaries, in this type of the vascular system. The ‘Father of the Physiology’ William Harvey discovered the closed circulatory system in the organisms back in 1616. The blood flow can also be regulated in the closed circulatory system.

Open Circulatory System vs. Closed Circulatory System

  • The blood flow in the open circulatory system takes place through the vacant spaces called sinuses and lacunae. Contrary to this, the closed vessels are present in the closed type of circulatory system and they are held responsible for the blood flow.
  • In open circulatory system, when the blood gets pumped by the heart, it gets stored in the cavity called Haemocoel, whereas in the closed circulatory system, Haemocoel is absent.
  • In open circulatory system, the blood transportation requires more time and the rate of supply and elimination of material is also quite low as compared to the closed circulatory system.
  • The open circulatory system is present in the invertebrates like molluscs and arthropods. On the other hand, the closed circulatory system is present in the invertebrates like earthworms and cephalopods.

Comparison Video