Circulatory system

• The heart is located between the lungs, behind the sternum.
• Blood flows from the right side to the left side of the heart through the septa.
• The heart has four chambers - two atria (upper) and two ventricles (lower).
• Mammals have a double circulatory system
• Blood in the right side of the heart is deoxygenated and the blood in the left side of the heart is oxygenated
• The heart is always shown as if you're facing a person so the right side is shown on the left and the left side is shown on the right
• The only organs named in the diagram are the kidneys
• Arteries


  Blood leaves the heart in arteries
• Arteries


  • Blood in the arteries is under very high pressure and the pressure increases every time the heart contracts
  • Blood continually moves forward in arteries even between contractions
• Pulmonary artery


  Carries deoxygenated blood from the heart to the lungs
• Aorta


  Carries oxygenated blood from the heart to the body
• Renal arteries


  Arteries that supply the kidneys
• Arterioles


  Blood vessels that blood passes through before reaching the organs
• Capillaries


  Sites of gas exchange where oxygen diffuses from the blood to the body cells and carbon dioxide diffuses from the body cells back into the blood
• Venules


  Blood vessels that blood passes through after leaving the capillaries
• Veins


  Carry the oxygenated blood away from the organs towards the heart
• Renal veins


  Veins that come from the kidneys
• Vena cava


  Very large vein that returns the deoxygenated blood back to the heart
• Pulmonary vein


  Carries the oxygenated blood from the lungs to the heart
• The structure of the different blood vessels depends on the function of each blood vessel
• The atria are thin-walled chambers that receive blood from veins.
• Valves are flaps made up of connective tissue with elastic fibers.
• The ventricles are thicker-walled chambers that pump blood out of the heart into arteries.
• Valves prevent backflow of blood within the heart.
• Each chamber has its own valve that prevents backflow of blood.