Circulatory System of Earthworm MCQ - Practice Questions with Answers

Circulatory System of  Earthworm

• The circulatory system of earthworm is of closed type and it consists of blood, blood vessels, heart and anterior loops, blood glands. 

Blood 

• The blood remains restricted to the blood vessels and heart as the circulatory system is closed.
• The blood is red due to the dissolution of hemoglobin into plasma. 
• Only one type of blood cells i.e. leukocytes are present in the blood. 
• The blood cells are phagocytic in nature

Blood vessels

• The blood vessels include dorsal blood vessels, lateral esophageal vessel, ventral vessel, commissural vessel and sub neural vessels. 
• Smaller blood vessels supply the gut, nerve cord and body wall.

Heart and anterior loops

• Four pairs of tubular hearts with valves are present in earthworm. Two of the pairs are lateral while the other two are posterior hearts. 
• Lateral hearts lie in the 7th and 9th segments.
• Posterior hearts are called latero-esophageal hearts and they are present in 12th and 13th segments. 
• Two pairs of anterior loops are also present in the 10th and 11th segments. 

Blood glands 

• On the 4th, 5th and 6th segments blood glands are present
• The function of these blood glands is to produce blood cells and haemoglobin 
• Haemoglobin is dissolved in blood plasma

In Earthworms, specialised kind of breathing devices are absent and respiratory exchange of gases occurs through the moist body surface into the bloodstream.