the heart

• Double circulation is when the blood passes through the heart twice in one circuit. An advantage is that it maintains blood pressure for fast flow of blood to body organs however a disadvantage of double circulation is that there are two pumps (heart) which means more energy used by the body
• The function of the heart is to pump blood around the body and it is made of strong cardiac muscle
• the blood vessel that takes blood to the heart, muscles, cells to supply them with oxygen and glucose for respiration is the coronary artery
• Vena cava → right atrium → tricuspid valve →right ventricle →semi lunar valve → pulmonary artery → lungs → pulmonary vein →left atrium → bicuspid valve →left ventricle → semi lunar valve → aorta → organs of the body

  R VATVSA VABVSA L
• valves prevent backflow of blood
• left ventricle has the thickest muscular wall because it needs high pressure to pump blood the furthest
• right atrium has the thinnest wall
• right atrium has the thinnest wall to pump blood to the right ventricle
• atria = upper chamber
• oxygenated blood is left
• deoxygenated blood is right
• Hole in septum - blood mixes, lower conc .of O2 in blood, less energy released by respiration