Step 1
Superior and inferior venal cava
Step 2
Right atrium
Step 3
Tricuspid valve
Step 4
Right ventricle
Step 5
Pulmonary valve
Step 6
Pulmonary arteries
Step 7
Lungs gas exchange
Step 8
Pulmonary veins
Steps 9
Left atrium
Step 10
Bicuspid valve
Step 11
Left ventrical
Step 12
Aortic valve
Step 13
Aorta
Step 14
Arteries
Step 15
Arterioles
Step 16
Arteriol capillaries
Step 17
Gas exchange
Step 18
Venous capillaries
Step 19
Venules
Step 20
Veins
Step 21
Superior and inferior venacava