The Equine Heart and Circulatory System
1. the aorta
2. the pulmonary artery
3. the pulmonary vein
4. the diaphragm
5. the left atrium
6. the left ventricle
7. coronary blood vessel- supplies                oxygenated blood to the heart muscle 
8. the right atrium
9. the anterior vena cava
A = anterior vena cava, which is the route by which deoxygenated blood returns from the body to the heart
Hint ~ the color of the text below will tell you whether the blood is oxygenated (red) or deoxygenated (blue) as it travels through the circulatory system.
B = the aorta, which is the route oxygenated blood takes to get to body tissues from the left side of the heart
C= the pulmonary artery, takes    deoxygenated blood from the right ventricle to the lungs. It is the only artery in both the equine and the human that carries unoxygenated blood
D= the pulmonary vein, returns             oxygenated blood from the lungs to    the left side of the heart, where it is    then pumped out to the aorta to the      body tissues. It is the only vein in the human and equine body that carries    oxygenated blood
E= left atrium, receives oxygenated       blood from the pulmonary veins, and    pumps it to the left ventricle.
F= left ventricle, receives blood from the left atrium and pumps it to the aorta
G= right ventricle, receives blood from the right atrium and pumps it to the       pulmonary artery, which takes blood     to the lungs for reoxygenation.
H=  right atrium, receives deoxygenated blood from the vena cava, and pumps it to the right ventricle

J= posterior vena cava, returns            deoxygenated blood from the lower     part of the body to the right atrium