Biology Science

Difference between Open and Closed Circulatory System

Main Difference

The main frame of a living body comprises of a system that carries out circulations all over the body, resulting in the uninterrupted functions of the body. This system scientifically termed as a Circulatory system, more commonly known as blood circulatory system for higher vertebrate organisms. The circulatory system is basically of two types, Open Circulatory system, and Closed Circulatory System. The open circulatory system is a fluid circulation system found in lower invertebrates like arthropods and mollusks. The fluid in open circulatory system can be hemolymph or blood in few cases. Whereas on the other hand closed circulatory system is found in higher vertebrates including humans. The circulation in the closed circulatory system takes places via a network of capillaries, vessels, veins, and arteries. Blood the fluid closed in vessels responsible for gaseous and other material exchange in every part of the body.

Comparison Chart

BasisOpen Circulatory SystemClosed Circulatory System
Found In

The open circulatory system is present in lower invertebrates like mollusks and arthropods.

The closed circulatory system is present in higher vertebrates including humans and other higher animals.

Mixture of fluids

Blood is mixed with other body fluids such as hemolymph.

Blood is not mixed with other body fluid and is enclosed in vessels.

Gaseous Exchange

No gaseous exchange takes place in an open circulatory system.

Gaseous exchange takes place between the blood capillaries and body tissues.
Blood FlowBlood flow is slow and uncontrollable in the open circulatory systemBlood flow is fast and is controlled by relaxation and extension of blood vessels.
Heart

Organisms with an open circulatory system lack true heart and other organs as well.

Organisms with the closed circulatory system have properly developed heart and other organs.

Blood PumpBlood is pumped directly to the whole body.

Blood is pumped by the heart and is transported via blood vessels.

 

Open Circulatory System

Open Circulatory System is a pathway or structural flow of body fluids like hemolymph or blood in all parts of the body. Such type of circulatory system is found in lower invertebrates most probably mollusks and arthropods. In this circulatory system, the blood is mixed with the other body fluids such as lymph and is randomly flown towards every portion and part of the body. Unlike a closed circulatory system, the open circulatory system does not possess any sort of network of veins, capillaries or any other blood vessels. The organs inside the body are directly showered with the blood and other fluid, which results in the direct exchange of useful and waste material. In the open circulatory system, a gaseous exchange does not take place, only food and nutrients are supplied. All the nutrients in the open circulatory system are directly exchanged by the tissues of the organs with blood. Although the open circulatory system does not possess any network of vessels but contains a single central dorsal blood vessel that supplies blood mixed with other fluids to every part of the body. The organisms possessing open circulatory system does not possess a true and full-fledged developed heart like in the higher vertebrates that has closed circulatory system. The blood volume in open circulatory system cannot be controlled, that’s why flow of blood in open circulatory system is quite slow as compared to the closed circulatory system.

Closed Circulatory System

The closed circulatory system is the kind of blood circulatory system found in higher vertebrates including humans, in which transportation of blood takes place inside the closed vessels. The closed circulatory system comprises of a well-established network of a variety of different blood vessels such as arteries, veins, and capillaries. The organisms possessing a closed circulatory system possess a proper developed heart and rest body organs that are interlinked with each other and the whole body via this vessel network. Arteries from the heart take oxygenated blood towards body parts. The arterial network is then further divided into small capillaries, which are responsible for gaseous and other nutrients exchange with body tissues. Similarly, a different capillary network takes the waste and deoxygenated blood from the body tissues and form a venous system. The veins are responsible for taking all the deoxygenated blood from the body towards the lungs. The blood flow in the closed circulatory system is controllable, as it is much faster and quicker as compared to an open circulatory system. The blood flow in the closed circulatory system is controlled by the relaxation and contraction of blood vessels.

Key Differences

  • The open circulatory system is found in lower invertebrates like arthropods and mollusks.
  • The closed circulatory system is found in higher vertebrates including humans.
  • Blood is intermixed with other body fluids in the open circulatory system.
  • Blood is separated from other body fluids and is enclosed in vessels.
  • The flow of blood is slow and is uncontrollable in the open circulatory system.
  • The flow of blood is fast and is controllable by contraction and relaxation of blood vessels in the closed circulatory system.
  • No gaseous exchange takes place in the open circulatory system.
  • Respiratory pigments are present in the blood for gaseous exchange in the closed circulatory system.
  • No true heart is found in organisms possessing an open circulatory system.
  • The properly developed heart is present in the organisms comprising of the closed circulatory system.

 

Video Explanation

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