Circulatory System Overview

Circulatory System Overview

• Animals have a complex network of blood vessels
• This network transports nutrients and removes waste products to and from cells throughout the body
• The system also carries oxygen and removes carbon dioxide

The Heart

• The heart is a complex muscle with two pumps
• One pump circulates blood to the lungs (pulmonary circulation)
• The other pump circulates blood to the rest of the body (systemic circulation)
• The heart has four chambers: two atria and two ventricles
• The heart is asymmetric with the left side larger than the right side
• The left side is larger because it pumps blood throughout the body in a larger circuit than the pulmonary circuit
• The right side of the heart handles the smaller circuit to the lungs

Blood Flow Through the Heart (Right Side)

• Deoxygenated blood from the body enters the right atrium through the superior vena cava and the inferior vena cava
• Blood flows from the right atrium into the right ventricle through the tricuspid valve
• The tricuspid valve prevents backflow

Blood Flow Through the Heart (Left Side)

• Blood flows from the right ventricle to the lungs to receive oxygen
• Then the now oxygen-rich blood comes back to the heart
• Blood flows from the lungs into the left atrium
• Blood flows from the left atrium into the left ventricle through the bicuspid (mitral) valve
• The bicuspid valve prevents backflow

Additional Details

• The heart has valves to control the direction of blood flow
• The heart is a pump
• Blood vessels are connected to the heart