cardio

Question 1

preload

Answer 1

amount of stretch on cardi muscle fires before they contract

-increased preload is more blood returning
-decresed preload is due to bleeding or dehydration

Question 2

afterload

Answer 2

pressure that ventricles must overcome to eject blood before semilunar valves open

afterload increaed in hypertension and atherosclerosis

afterload decreased in blood loss and vasodilation

Question 3

contractility

Answer 3

force of contraction of individule fibres

increased by + inotropic such as epinephrine, thryroxine

decreased by -ve intorope such as hypoxia or acidoss

Question 4

stroke volume

Answer 4

pumped out of LV per beat
sv= end diastolic volume - end systolic volume
-around 70ml a min

end diastolic = vol blood in ventricles at end of filling

end systolic = vol blood in ventricle at end of contraction

Question 5

Cardiac output

Answer 5

= hr x sv
blood ejected to aorta/pulm trunk each time

Question 6

cardiac reserve

Answer 6

= max CO - min Co