Frank starling law

Question 1

what is the cardiac output?

Answer 1

volume of blood pumped by each ventricle per minute

CO= SV x HR

Question 2

what is the stroke volume?

Answer 2

• volume of blood ejected by each ventricle per heart beat

Question 3

how do you calculate the stroke volume

Answer 3

SV = EDV - ESV

Question 4

what is the diastolic stretch of myocardial fibres determined by?

Answer 4

• the end diastolic volume

Question 5

what is the preload

Answer 5

the diastolic stretch of the myocardial fibres (end diastolic volume)

Question 6

what is the end diastolic volume determined by?

Answer 6

the venous return to the heart

Question 7

what is frank starling’s law of the heart?

Answer 7

the more the ventricle is filled with blood during diastole, the greater the volume of blood that will be ejected in the resulting systolic contraction

Question 8

what is the after load?

Answer 8

the resistance to into which the heart is pumping

Question 9

what effect does prolonged increased after load have on the heart?

Answer 9

• the heart is unable to eject full SV so will have greater EDV
• therefore force of contraction rises, if this persists the ventricular muscle mass will increase to overcome resistance

leading to ventricular hypertrophy

Question 10

what affect do sympathetic nerves have on the heart?

Answer 10

• positive inotropic ( force of contraction )and chronotropic (rate) affect

Question 11

what affect does sympathetic activation have on the frank starling curve

Answer 11

contractility of the heart at a given EDV increases, therefore the graph is shifted to the left

Question 12

what can cause the frank starling curve to shift to the right?

Answer 12

heart failure

Question 13

what is the effect of parasympathetic system on the heart?

Answer 13

• decreases heart rate
• has no effect on the ventricular contraction/ SV