Cardiac Muscle Flashcards
cardiac muscle has smaller
sarcomere units ( like skeletal muscle)
does cardiac muscle branch
yes–unlike skeletal
junction between cardiac cells
intercalated discs (unlike skeletal)
intercalated disks for
fast communication between cells–gap junctions–heart contraction all-or-nothing
Desmosomes–cell body for adhesion
membrane surrounding cardiac muscle cells
sarcolema
higher demand than skeletal thus
more T tubules, ATP, sarcoplasmic reticulum, slow Ca gates (allows for continuous contractal state)
CCB
calcium channel blockers–decreases FORCE of contraction of heart
arythmias happen during
end of absolute refractory period
Ventricular Function measured by
Frank-Starling Curve– length-tension curve for heart (although not same as skeletal muscle shortening)
which muscle type has more available Ca
cardiac–for sustained contractability
heart failure means
lower stroke volume (amount of blood heart pushes out)
volume of blood in heart after filling
end-diastolic volume
beta-blocker
negative inotrope
stroke volume at aorta
Afterload
X-axis: stroke volume
Y-axis: outflow resistance (afterload)
If resistance is high–output will be low
enlargement of heart walls (cardiomyopathy)
hypertrophy–usually most noticeable at apex–will decrease volume able to enter ventricle
hypertrophic heart complications
stiffening of wall
decreased volume
myocardial labs
- cardiac troponins: released into blood when heart damaged i.e MI
- Serial Troponins taken–series over time
Cell structure specialized for cell-cell adhesion btwn cardiac muscle cells
Desmosome–
Agent that alters the force of energy of cardiac muscle contraction
Inotrope–negative inotropic agents weaken force of muscle contraction
Increase velocity of contraction and SV
Positive inotropes
Decrease velocity of contraction and SV
Negative inotropes
Amount of resistance to ejection of blood from LV
Afterload
Muscle with no troponin
Smooth muscle
Less myosin
Smooth muscle– calmodulin
