double system

• blood passes through the heart twice for each complete circuit
• in mammals the heart is divided down the middle
• right side of the heart pumps blood to the lungs to pick up oxygen
• from the lungs blood travels to the left side of the heart which pumps it too the rest of the body
• when blood returns to the heart it enters the right side again
• our circulatory system is 2 loops one sends blood to the lungs and the other sends blood to the rest of the body
• pulmonary system - sends blood to the lungs
• systemic system - sends blood to the rest of the body
• an advantage to a double circulatory system is the heart can give the blood an extra push between the lungs and the rest of the body, blood travels faster and oxygen is delivered to the tissues quicker