7.4 - Structure of the Heart

• number of pumps in the heart

  two pumps side by side

  pump on the right deals with deoxygenated blood from the body

  pump on the left deals with oxygenated blood from the lungs
• why are two pumps needed?

  blood has to pass through very tiny capillaries so there's a huge drop in pressure so blood flow to the rest of the body would be very slow

  so blood returns to the heart to increase its pressure so it cango around the body
• chambers in the heart

  left and right atrium

  left and right ventricle
• valves in the heart

  left atrioventricular valve ( bicuspid)

  right a trioventricular valve (tricuspid)

  semilunar valves
• vessels connected to the 4 chambers

  aorta

  vena cava

  pulmonary artery

  pulmonary vein
• atrium

  thin-called and elastic so stretches as it collects blood
• ventricle

  thicker muscular wall as it has to controut more strongly to pump blood out of the heart
• right ventricle

  thinner muscular wall as it only has to pump blood to the lungs so contracts less strongly as distance is shorter
• left ventricle

  thicker muscular wall as it contracts more strongly so higher pressure to pump blood all around the body
• atrioventricular valves

  link atria to ventricles and stop blood flowing back into the atria when ventricle contracts
• semi lunar valves

  link ventricles to pulmonary artery & aorta

  stop blood flowing back into the heart after ventricles contract
• cords

  attach atrioventricular valves to ventricles to stop them being forced up into the atria when ventricles contract
• aorta

  connected to left ventricle

  carries oxygenated blood to all parts of the body, exept the lungs
• vena cava

  connected to right atrium

  brings deoxygenated blood back from tissues
• pulmonary artery

  connected to right ventricle

  Carries deoxygenated blood to lungs where oxygen is replenished and carbon dioxide remorad
• pulmonary vein

  connected to left atrium

  brings oxygenated blood from the lungs
• coronary arteries

  blood vessels that supply the heart which branch off the aorta shortly after it leaves the heart
• blockages in coronary arteries

  can lead to myocardial infarction because an area of the heart is deprived of blood so muscle calls in that area can't respire so die