Starlings Law Flashcards
What is starlings law
The more that the heart contracts the more blood that would be pushed out of the heart
Can do this by increasing the:
Contractility
The preload
The after load
What is the term used for heart rate
Chronotrophic
Positive: increased heart rate
Negative: decreased heart rate
What is the term used for contractility
Inotrophic
Positive: increased contractility
Negative: decreased contractility
What can increase the heart rate
Increased adrenaline/noradrenaline
Increased ca2+
Temperature
Hormones
Excersise
What can decrease the heart rate
Increased potassium
Decreased neurotransmitters
Decreased Ca2+
What 3 things is stroke volume based on
Preload
Contractility
After load
What is the preload
The stretch of the ventricles in diastole - EDV
What can increase the preload
Venous tone
Skeletal muscle pump
Respiratory pump
Venous tone (the more contraction of the veins would pump more blood back up to the heart)
Gravity (more when lying down)
What would increased venous return do to the contractility
Would have the increased blood return to the heart
Would then increase the Left ventricle end diastole pressure
More blood would then be pumped out
Increased stroke volume
What is the afterload
The resistance needed to overcome the ventricles to pump blood to the aorta
What would increased afterload do to the stroke volume
Decrease
More pressure would be needed to overcome
So would decrease some of the blood that would be able to leave the heart
What factors would increase the afterload of the heart
Increased vascular resistance (harder to push the blood out, so more afterload)
Semilunar valve damage (not working properly so less out)
What would decrease after load
The decreased vascular resistance
