Acute CV (ppt 2)

• The average pressure outside our heart is the average aortic blood pressure and is important in holding the aortic valve shut
• Preload factors are:

  1. Blood volume
  2. Skeletal muscle pump
  3. Abdomino-thoracic pump
• For more preload, we want more:

  1. Ventricular compliance
  2. Atrial Contractility
  3. Aortic Pressure
  4. Central Venous pressure

  We want less:

  1. Heart rate
  2. ventricular contractility
• Ventricular compliance is the ability to accept blood from the atria and pump it into the ventricles
• Atrial Contractility is how efficient our atria is at pumping blood out
• Aortic pressure is the pressure exerted by the aorta on the walls of the heart (greater diastolic pressure)
• More Central venous pressure is important because it gets more blood back into the heart
• We can increase our stroke volume by increasing our ventricular contractility by going from parasympathetic to sympathetic

  This relates to the Frank-Starling mechanism
• Smaller ventricle volume results in a higher afterload
• blood pumping out of the arteries?

  systole
• A small increase in preload (pressure on ventricles) due to the atria contracting is called the atrial kick
• End systolic volume?

  The amount of blood left in heart after contraction
• The heart can self- depolarize and this is known as automaticy
• SAP of the heart:

  1. SA nodes is the pacemaker
  2. AV node holds the signal and allows atria to contract causing atrial kick
  3. Punjike fibers contract heart
• A FIB is when what is subdued causing ventricular to contract on its own?

  SA node
• Extrinsic Regulation:

  Norepinephrine innervates the SA node released from the sympathetic system

  Aceytlcholine is released in the SA node and decreases heart rate
• Inotropy - Contractility

  Chronotropy - Heart rate
• Sit to stand increases heart rate and decreases stroke volume, why?

  Blood shifts down to feet, preload goes down as there is less blood volume, which decreases stroke volume
• After about 10 minutes of prolonged moderate-intesity exercise, heart rate increases steadily, while stroke volume goes down and CO remains the same. This is called?

  Cardiovascular drift
• VO2 max = CO x A-VO2Diff
• Rate Pressure Product: HR time systolic
• Double product tells us how hard the heart works
• Both muscle pumps being utilized and creating a sympathetic tone and the utilization of the Frank Starling mechanism after a workout increases what? These two increase what?

  EDV and contracitlity, resulting in an increase in stroke volume
• Size of the heart chamber is bigger means?

  More room: Bigger preload and higher SV and CO
• The wall of the heart is bigger means is what type of hypertrophy?

  coencentric hypertrophy
• Size of the heart chamber is bigger is what type of hypertrophy?

  Eccentric