Hear beat and blood pressure

• what causes the noise of the heart beat?

  the sound of the blood hitting a closed valve
• what is systole?

  Contraction - usually referring to ventricular contraction
• what is diastole?


  relaxation, or the rest of cycle: ventricular relaxation and filling
• what are the basic stages of the cardiac cycle?

  atrial contraction, isovolumetric contraction, ventricular ejection, isovolumetric relaxtion, ventricular filling
• how long does the cardiac cycle last?

  0.8 sec
• how to calculate maximum heart rate?

  220 - age
• what are Korotkoff sounds?

  Lubb Dupp
• what is Lubb sound?


  turbulence caused by the closure of AV valves, hitting valves and ventricle walls
• What is Dupp sound?

  turbulence caused by semilunar valves closing
• what are the 3rd and 4th sounds from?

  ventricular filing and atrial systole. 4th Sound audible when ventricles are stiff
• Atrial systole

  • atria contracr
  • AV valves open
  • slight increase in atrial pressure
• how to calculate end diastolic volume?

  Ventricular vol + atrial contribution
• isovolumetric contraction:

  • All valves closed
  • beginning of systole
  • increase in intraventricular pressure from contraction
  • heart shape change but no blood is ejected
  • pushes AV valves close
  • FIRST SOUND
• Rapid ejection:

  • AV valves close, other open
  • Intraventricular P is higher than aortic and pulmonary P, the valves open and blood is ejected
  • Atria continue to fill
  • Should be silent if noise problem with valves, shunt
• Reduced ejections:

  • Aortic and pulmonary valves stay open and AV valves stay closed
  • no blood movement
  • ventricular muscle relaxtion
  • Ventricular P decreases slightly but blood still leaves the heart (kinetic energy). Atrial P increasing as atria continue to fill
• Isovolumetric relaxation:

  • valves close, aortic first then pulmonic valve
  • ventricle volume remains the same as valves are closed (diacrotic wave)
  • Atrial pressure and volume increase from venous return
• How to work out cardiac output?

  Cardiac output = heart rate x stroke volume
• How to calculate stroke volume?

  end-diastolic volume - end systolic volume
• what is End-systolic volume determined by?

  preload, contractility, afterload
• what is EDV roughly?

  130ml
• what is ESV roughly?

  60ml
• what affects heart rate?

  • Neural control: physical or emotional stress
  • Ion levels
• how do calcium levels affect heart rate?


  too little a weak muscle contraction, too much too long contraction
• what is starlings law?

  what enters the heart is directly proportional to what leaves the heart
• what is preload?


  How stretchy is the heart at max fill
• What is afterload?


  The pressure against which the heart need to pump to expel blood
• what is afterload related to?

  lumen size
• what is contractility?


  the ability of the muscle to produce a force
• what is the skeletal muscle pump?

  Mechanism by which skeletal muscles contract and relax to help propel blood through veins back to the heart.
• why is the skeletal muscle pump needed?

  The veins lack muscle
• what does skeletal muscle pump affect?

  opens downstream valves
• how to calculate blood pressure?

  cardiac output X total peripheral resistance
• what is blood pressure?

  The pressure of blood on the wall of the blood vessels
• what is normal blood pressure?

  120/80
• what is high blood pressure?

  >130/85
• what is peripheral resistance?

  The degree of friction encountered by blood
• what causes friction?

  • constriction / narrowing
  • increased blood volume
  • viscosity#
• what affects viscosity?


  cold, increased red blood cells, dehydration
• how to calculate pulse pressure?


  systolic Bp - diastolic Bp
• what detects pressure?


  baroreceptors in arterial carotids and aoritc arch