Force generation by the heart Flashcards
cardiac muscle
striated due to regular arrangement of contractile protein
what do desmosomes ensure
that the tension develope by one cell is transmitted to the next
contractile units of muscle
myofibrils
actin
thin filament
myocin
thick filaments
what are actin and myocin arranged into
sarcomeres
how is muscle tension produced
by sliding of actin filaments on myocin filaments
where is ca+ released from
sracoplasmic reticulum
cross bridge binding
when the muscle fiber is excited ca+ binds with troponin pulling troponin tropomysoin complex aside to ezpose cross brudge binding site
what does the long refractpry period prevent
generation of tetanic contraction
refractory period
period following an action potential in which it isnt possible to produce another ap
stroke volume
the volume of blood ejected by each ventricle per heartbeat
calc for stroke volume
EDV-ESV
Intrinsic control of stroke volume
changes are broiught about by changes in the diastolic length/ diastolic stretch of myocardial fibers
end diastolic volume
volume of blood in each ventricle at the end of diastole
what does the end diastolic volume dtermine
preload
what is the end diastolci volume determined by
venous return to the heart
frank starling curve
states that the more the ventricle is filled with blood during diastole the greater the volume of ejected blood will be during the resulting systolic contraction
skeletal optimal fibre length
atresting
cardioac muscle optimal
stretching
increased afterload
eventually the ventricular msucle mass increases to overcome resistance - hypertension
afterload
resistance into which the heart is pumping
positive inotropic effect
stimulation of sympathetic nerves increase the force of contraction;noradrenaline
effect of sympathetic nerve stimulation on frank starling curv
shifts to left
how does heart failure affect frankstarling
shifts to right
cardiac output
volume of blood pumoed by each ventricle per minute
calc for co
sv x hr
What feature of cardiac myocytes allows for the transmission of ions between adjacent cells
intercalated discs
