What is the type of circulatory system present in arthropods? Do these animals have heart and respiratory pigments?
In arthropods the respiratory system is open (lacunar). Blood, also known as hemolymph, is pumped by a heart and falls into cavities (lacunas) irrigating and draining tissues. All arthropods have a heart. Crustaceans and arachnids have respiratory pigments. Insects do not have respiratory pigments since their blood does not carry gases (in them gases reach tissues and cells through tracheal structures).
