PV Loops and Starlings Law

Question 1

What does the red line represent and what can cause this

Answer 1

increased inotropic state

Increased sympathetic nerve firing to the heart of administration of a beta agonist

Norepinephrine increases calcium current, which elevates cytoplasmic calcium levels during systole, resulting in more cross-bridge formation, and consequently more force.​

Question 2

What is represented by the red line and what can cause this change

Answer 2

Decreased afterload

Systemic arteriolar dilation following administartion of a vasodilator or development of anaphyactic shock

Question 3

What does the red line represent and what can cause that

Answer 3

Decreased inotropic state

Reduced sympthetic firing to the heart or administration of a beta antagonist

Question 4

What is represented by the red line and what happens to systolic arterial pressure

Is there a difference in inotropic state?

Answer 4

decreased preload

Systolic arterial pressure is decreased tcompared to normal because of decreased stroke volume

No difference in inotropic state bc it follows same Po line

Question 5

What is represented by the red line and what causes this

Answer 5

ventricular hypertrophy

Ventricular hypertrophy results in more sarcomeres within larger myocytes, and so increased force can be generated. This is shown above by the leftward shift in the Po curve. ​

Question 6

Answer 6

B

Question 7

What is represented by the red line and what can cause this

Answer 7

Incresed afterload

Systemic arteriolar constriction following administration of a vasoconstrictor

Question 8

Answer 8

Question 9

How does the increased force due to hypertrophy differ from increased force due to increased inotropy

Answer 9

The increased force due to hypertrophy - increased size of myocytes, more cross-bridges

increased force due to increased inotropic state - increased cytosolic calcium levels​

Question 10

Answer 10

D

Question 11

What causes the red line

Answer 11

Increased preload

Question 12

what is starlings law

Answer 12

the stroke volume increases when the preload is increased

Question 13

increased force of contraction at greater preload is due to what

Answer 13

increased stretch which results in more favorable overlap of thick and thin filaments

Question 14

what are the determinants of preload

Answer 14

filling time (heart rate)

Rate of venous return (venous tone, blood volume, gravity)

Question 15

Answer 15

Question 16

Answer 16

Question 17

Answer 17