Preserving Cardiac Output in Acute Stress Flashcards
True/False: In relaxed muscle, myosin head binds to actin
False
In relaxed muscle, Tropomyosin blocks the binding site
True/False: In contracting muscle, tropomyosin blocks the binding site
False
Myosin head binds to actin for the power stroke to occur
On the Tension-Length curve for cardiomyocytes, what does it mean when the curve is shifted right?
Shifted right -> calcium sensitivity is less because it takes more Ca to generate the same force
On the Tension-Length curve for cardiomyocytes, what does it mean when the curve is shifted Left?
Shifted left –> calcium sensitivity is greater because less Ca generates more force
Most beta-agonists are (circle one) inotropes/lusitropes
inotropes
- contractility
What is the pretentious word for heart rate?
Chronotropy
List some Factors that influence EC50(calcium sensitivity) include:
□ pH □ Temp □ Sarcomere length □ Contractile protein phosphorylation □ Caffeine ↑s in Ca2+ ↑ strength of contraction
What is the effect of increasing preload on force of contraction:
the greater the volume of blood entering the heart during diastole (EDV), the greater the volume of blood ejected during systolic contraction (SV) and vice versa
Stroke volume is a reflection of ________
end diastolic volume (EDV)
EDV-ESV
In the Frank-Starling SV-LVEDP graph, a rightward shift indicates? Leftward?
Rightward: decreased inotropy
Leftward: increased inotropy
(contractility)
Via ______ ‘s law, an increase in preload, _____ SV on the next beat
Starlings, Increases SV
graph widens
Increased ______ decreases SV on the next beat
afterload
graph shortens
Increased ______ increases SV on the next AND ______ beats
inotropy, subsequent
graph widens and gets taller
