The system involved in the transport of various substances within the body of an animal is called Circulatory System. The circulatory system transports gases like O2, CO2 etc. nutrients, wastes, hormones and defense proteins.
There are two types of Blood Circulatory Systems found in animals:
In this type of Circulatory System blood flows through the spaces among tissue so it directly comes in contact with tissues. It remains filled in the open tissue spaces called Sinuses. After exchange of materials with tissues, blood enters the pumping organs or heart which pumps it into blood vessels. These vessels again drain out blood into sinuses so it remains in Circulation.
Example: This type of circulatory system found in arthropods and molluscs.
This type of system allows blood to flow inside the closed tubular blood vessels and never comes out in direct contact with tissues.
Example: Human and Most vertebrates and some invertebrates such as, Annelid like earthworm, have a closed circulatory system.
