Cardiac muscle mechanics Flashcards
isometric contraction
Example?
the muscle contraction doesn’t have muscle varies in length
holding a book
isotonic contraction
example
the muscle contraction with constant tension while muscle varies in length
contractility of heart
equal to pressure of the heart x volume of blood
In heart, what is the preload?
the end- diastolic -volume of blood
In heart, what is the afterload?
the arterial pressure against the ventricle contractions
What will result in if EDV increases?
the resting sarcomere length of ventricle increases -> more force generation -> SV increases
Explain what happen in this figure?
the resting sarcomere lenght can increase (hypertrophy) to increase the force against afterload (arterial pressure)
What happen to the SV if we increase the arterial pressure?
SV decreases because velocity of ventricular shortening muscle decreases
What is the mechanism of increasing resting sarcomere length will increas SV?
it will create more cross bridge formation -> increase sensitivity of troponin to Ca2+
Starling’s Law of the Heart
the SV increases when filling pressure increases (EDV increases)
when the venous blood return increase -> EDV increases -> SV increases
