cardiac cycle

• what is systole?

  period of atrial or ventricular contraction
• what is diastole?

  period of atrial or ventricular relaxtion
• key points of diastole?

  • all heart muscles relax
  • high blood pressure in arteries
  • semi-lunar valves close as to prevent backflow into ventricles
• key points of atrial systole?

  • both atria contract
  • blood into ventricles
  • atrioventricular valves open, due to high blood pressure
• key points of ventricular systole?

  • ventricular walls contract, forcing blood into aorta
  • blood pressure forces atrio-ventricular valves to close
  • pressure opens semi-lunar valves
• why is the pressure change in the left ventricle much higher than the right during atrial contraction?

  blood has to travel further from the left. left = whole body, right = lungs
• blood flows from a high pressure to a low pressure, unless blocked by a valve
• the coronary artery supplies oxygenated blood to the heart muscle itself.
• coronary veins drain blood away from the heart muscle.
• capillaries are tiny vessels where gas exchange occurs between the blood and tissues.
• arterioles are small vessels that branch off from an artery and lead to capillaries.
• arteries have thicker walls with elastic tissue that can stretch when blood enters them, allowing them to expand without bursting.
• arterioles are small branches off an artery which supply capillaries with oxygenated blood.
• 1 - superior vena cava

  2- right atrium

  5- left atrium

  
• 7- pulmonary veins

  8- inferior vena cava

  
• why does the right ventricle have thinner walls than left?

  • it only pumps blood to lungs which is a shorter distance than left.
  • it has to be delivered at lower pressures as to not damage capillaries in the lungs and to allow time for gas exchange
• pulmonary vein carries oxygenated blood from the lungs to the left atrium
• vena cava - carries deoxygenated blood from the body to the right atrium
• pulmonary artery carries deoxygenated blood from right ventricle to lungs
• where are semi-lunar valves found?

  aorta and pulmonary artery
• where are atrioventricular valves found?

  between atrium and ventricle