Preserving Cardiac Output in Acute Stress Flashcards

1
Q

True/False: In relaxed muscle, myosin head binds to actin

A

False

In relaxed muscle, Tropomyosin blocks the binding site

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2
Q

True/False: In contracting muscle, tropomyosin blocks the binding site

A

False

Myosin head binds to actin for the power stroke to occur

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3
Q

On the Tension-Length curve for cardiomyocytes, what does it mean when the curve is shifted right?

A

Shifted right -> calcium sensitivity is less because it takes more Ca to generate the same force

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4
Q

On the Tension-Length curve for cardiomyocytes, what does it mean when the curve is shifted Left?

A

Shifted left –> calcium sensitivity is greater because less Ca generates more force

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5
Q

Most beta-agonists are (circle one) inotropes/lusitropes

A

inotropes

  • contractility
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6
Q

What is the pretentious word for heart rate?

A

Chronotropy

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7
Q

List some Factors that influence EC50(calcium sensitivity) include:

A
□ pH
□ Temp
□ Sarcomere length
□ Contractile protein phosphorylation
□ Caffeine			   
↑s in Ca2+   ↑ strength of contraction
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8
Q

What is the effect of increasing preload on force of contraction:

A

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

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9
Q

Stroke volume is a reflection of ________

A

end diastolic volume (EDV)

EDV-ESV

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10
Q

In the Frank-Starling SV-LVEDP graph, a rightward shift indicates? Leftward?

A

Rightward: decreased inotropy

Leftward: increased inotropy

(contractility)

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11
Q

Via ______ ‘s law, an increase in preload, _____ SV on the next beat

A

Starlings, Increases SV

graph widens

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12
Q

Increased ______ decreases SV on the next beat

A

afterload

graph shortens

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13
Q

Increased ______ increases SV on the next AND ______ beats

A

inotropy, subsequent

graph widens and gets taller

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