Lecture 13 Integration of Cardiac and Vascular Functions

Question 1

What is reflected by the slope of the Frank-Starling (SV x preload) curve?

Answer 1

Contractility = Inotropic status

Question 2

What raises contractility/inotropic status of Frank-Starling curve?

Answer 2

SNS, inotropic drugs, hormones, conditioning

Question 3

What are 4 ways to assess cardiac function?

Answer 3

1. Frank-Starling Curve = measures contractility/inotropic status
2. Force of contraction x velocity (changes in preload don’t change vmax but do shift the Fv curve)
3. Pressure-volume loop (affected by changes in preload, afterload, contractility)
4. Max dP/dt (measure of contractility)= instantaneous rate of change of left ventricular pressure (max slope of LV pressure during cardiac cycle)
5. Ejection Fraction (>.5 in a normal heart) = SV/EDV

Question 4

In the Force of Contraction vs. Velocity curve, when force of contraction or afterload is high, velocity is _____?

Answer 4

low

bec/ force and velocity are inversely proportional

Question 5

Does increased contractility change vmax in the force of contraction vs. velocity curve?

Answer 5

Yes! Increases

Question 6

What is the velocity at peak tension/force on the force of contraction vs. velocity curve?

Answer 6

v=0 so this is an isometric contraction

Question 7

Ischemia, heart failure, infarction, bed rest reduce ____ of the heart?

Answer 7

Contractility

Question 8

What is afterload?

Answer 8

arterial or ventricular pressure during systole

Question 9

What is preload?

Answer 9

degree of filling of the heart before contraction

Question 10

The Treppe/Staircase effect (higher HR along with greater force of contraction due to building up of force over several beats) occurs when ______ and_____ are constant, thus representing a change in -_____.

Answer 10

preload, afterload are both constant

change in contractility

Question 11

Which has a greater effect on contractility, SNS or PNS?

Answer 11

SNS