Regulation of Cardiac Output & Blood Pressure Flashcards
How do we measure the efficiency and work of the heart as a pump?
Cardiac Output (CO)
What is the cardiac output?
Volume of blood the heart pumps out every minute (ml/min or L/min)
What is cardiac output determined by?
Stroke Volume (SV)
Heart Rate (HR)
What is Stroke Volume?
Volume of blood ejected by the left ventricle with each heartbeat. (Ml/beat)
How can cardiac output be adjusted?
Adjustments to SV and HR
What does and increase in SNS or Sympathetic tone =
Increased heart rate
What does increase in PNS or Parasympathetic tone =
Decrease in heart rate
What are the determinants of SV?
Pre load
After load
Cardiac contractility
What is preload?
The workload imposed on the heart before contraction begins.
What does the preload = to
The end diastolic volume or pressure (EDV/P)
What is EDV/EDP?
volume of blood or pressure in the ventricle prior to contraction (i.e. at the end of diastole)
What is the frank sterling law of the heart?
SV is directly proportional to Preload (or VR)
Preload
How is cardiac output calculated?
CO = SV x HR
What is the afterload?
The “load” against which the heart must contract in
order to eject blood into the aorta
