Chapter 14 Cardiac output, blood flow, blood pressure Flashcards
What is cardiac output?
Volume of blood pumped per minute by each ventricle
What is average resting cardiac rate?
about 70 beats per minute
What is the average stroke volume? (Volume of blood pumped per beat by each ventricle)
70-80 ml per beat
Cardiac output equation
Cardiac output (ml/min)=Stroke Volume (ml/beat) X cardiac rate (beats/min)
What is total blood volume average?
5.5 L
Stroke volume is regulated by which 3 variables?
End Diastolic volume (EVD)-volume of blood in ventricles st end of diastole
Total peripheral resistance-frictional resistance or impedance to blood flow in arteries
Contractility-or strength of ventricular contraction
What is EDV?
amount of blood in the ventricles immediately before they begin to contract
Sometimes called “preload”
Stroke volume is directly proportional to the
preload
An increase in EDV results in an
increase in stroke volume
Stroke volume is also directly proportional to
contractility, when ventricles contract more forcefully, they pump more blood
During exercise the cardiac rate
increases as a result of decreased vagus nerve inhibition of the SA node.
The cardiac control center is affected by higher brain areas and by
sensory feedback from pressure receptors (BARORECEPTORS)
Fall in blood pressure can produce a
reflex in heart rate
The higher the peripheral resistance, the higher the…
pressure
The greater the peripheral resistance, the ….
lower the stroke volume
