Question

Mention briefly about the circulatory system of earthworm.

Answer 1

• Earthworms show a closed blood vascular system. It means that blood flows in closed blood vessels.
  
• The circulatory system consists of blood, blood vessels, capillaries, and heart. Blood is circulated in one direction due to the contractions.
• The 4th, 5thand 6th segments have the blood glands, which produce the blood cells and haemoglobin. The blood cells do not have haemoglobin and are phagocytic. It is dissolved in the blood plasma.
• There are three main vessels that supply the blood to organs within the earthworm :
  

1. The aortic arches function like a human heart. There are five pairs of aortic arches, which have the responsibility of pumping blood into the dorsal and ventral blood vessels.
2. The dorsal blood vessels are responsible for carrying blood to the front of the earthworm’s body.
3. The ventral blood vessels are responsible for carrying blood to the back of the earthworm’s body.