3. [7 pts] At the onset of moderate exercise, the tensing of the muscles involved plus an increase

in venomotor tone produces a decrease in venous compliance, thereby raising Pms-

Sympathetic stimulation leads subsequently to an increase in heart rate by 40% and doubling

Qc,max from its normal value. Vaso- and venomotor tone also increased by 40%. Then, local

vasodilation of the muscular vascular beds produces a marked decrease in peripheral

resistance by 40% in both arterial and venous vasculatures. The following are the parameter

values under normal resting conditions:

f

CD

Cs

Qcmax

РА

Ppl

RA

Ry

CA

Cy

V

= 72 beats min¹²

= 0.035 L mmHg ¹

= 0.0007 L mmHg¹

13 L/min

= 100 mmHg

= -4 mmHg

= 19.2 mmHg min L¹¹

= 0.4 mmHg min L²¹

= 0.028 L mmHg ¹

= 0.5 L mmHg¹¹

= 3.7 L (total blood volume that exerts stress, aka stress volum)

a) [5 pts] Use MATLAB to plot the cardiac output and venous return curves during moderate

exercise on the same plot as the normal curves (see hold function). Add legend to the plot

(see legend function to indicate which graph is Qc or QR and under which condition -

normal or exercise.

b) [1 pt] From the plot, determine the steady-state operating value of cardiac output if an

increase in heart rate and Qc,max are the only responses to moderate exercise.

c) [1 pt] From the plot, determine the steady-state operating value of cardiac output when

heart responses change with the systemic circulation.

d) [1 pt] Copy and paste the MATLAB code you used in this question. You may take a picture

of your MATLAB script, but please make sure that the code is clearly readable from the

image.