Difference Between Open and Closed Circulatory System

Difference Between Open 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 type of circulatory system namely: Open and closed circulatory systems. The main difference between open and closed circulatory system is the way blood flows in an organism. Blood can flow through vessels inside the body such as arteries and veins. This type of circulation is called closed circulation. Open circulation happens when there are no vessels to contain the blood and it flows freely through the cavities of the body.

Difference Between Open and Closed Circulatory System

Vertebrates and few invertebrates have a closed circulatory system. The open circulatory system on the other hand is most commonly seen in invertebrates such as cockroaches and crabs. The other major difference between Open and Closed Circulatory System are summarized below:

Difference Between Open and Closed Circulatory System

Open Circulatory System (OCS)

Closed Circulatory System (CCS)

Blood flows through open spaces

Blood flows through closed spaces

The open spaces are called sinuses and lacunae

Closed spaces involve arteries and veins

The velocity at which blood flows is slow

Blood flows at a comparatively higher velocity

Organisms that have OCS have haemocoel

CCS organisms don’t have haemocoel

The time it takes to circulate nutrients and eliminate wastes are high

The time it takes to circulate nutrients and eliminate wastes are low

Blood flow cannot be regulated

Blood flow can be regulated

Organs come in direct contact with blood

Organs are not in direct contact of blood

Organisms with OCS: Snails, clams, cockroaches and spiders

Organisms with CCS: Humans, squids, Cats, earthworms

Conclusion

Vertebrates and Invertebrates possess one of two types of circulatory systems. Namely, open circulatory system and closed circulatory system. Open circulatory system is primarily found in invertebrates. Here, the blood flows freely through cavities and there is no vessels to conduct the blood. Closed circulatory system, on the other hand is found in vertebrates and a few invertebrates like earthworms. This system has the presence of vessels that conduct blood throughout the body.

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