The changes in metabolic activity associated with endothermy and the change from gill to lung respiration has led to changes in vertebrate circulatory systems. Veins between two capillary networks are ...

This system is perfect for mammals who need to circulate lots of oxygen in order to keep up their active lifestyles. Fish have a circulatory systems with just one circuit. Their hearts pump oxygen ...

Spread the loveCardiovascular training, often referred to as cardio, is an exercise system primarily focused on improving the ...