Cardiovascular Physiology

Question 1

Increase in HR increses ___.

Answer 1

• Contractility

Question 2

What is preload, what increases it?

Answer 2

• Volume of blood in ventricles at EDV
• Increased in:
  
  • hypervolemia
  • Regurgitation of cardiac valves
  • Heart failure

Question 3

What is afterload what increases it?

Answer 3

• resistance left ventricle needs to overcome to circualate blood
• Another way to think of it is the Foce opposing the contraction or wall stress during ejection
• Increased in:
  
  • Htn
  • Vasoconstriction
• Increased afterload =Increased cardiac workload

Question 4

How does an increased preload affect afterload?

Answer 4

It increases afterload

Question 5

How will an increase in afterload affect preload?

Answer 5

Increases preload as SV has decreased

Question 6

What is fick principle?

Answer 6

• Cardiac output is = to oxygen consumption / ( oxygen in pulm vein- oxygen in pulm artery)

Question 7

What is pressure work?

Answer 7

Aortic pressure

Question 8

What is minute work?

Answer 8

CO x aortic pressure

Question 9

What is stroke work?

Answer 9

SV x aortic pressure

• work performed by the LV

Question 10

Change in inotropy will shift the curve up or down when looking at relationship btw CO and Venous return, so increasing contractility increases CO without changing ___.

Answer 10

EDV

Question 11

What is the vascular function curve?

Answer 11

• Relationship btw CO and venous return
• Cardiac output is replaced by venous return
  
  • starling mechanism indicates they’re equal
• Right atrial pressure replaces EDV (equillibrium is at 2)

Question 12

As RAP increases Venous return ____

Answer 12

As RAP increases, Venous return decreases

Question 13

When is venous return at its max?

Answer 13

At low RAP

Question 14

Mean systemic filling pressure is the _____.

Answer 14

• Mean systemic filling pressure is the pressure in the vasculature when there is no flow
• Usually 7 mmHg with normal blood volume

Question 15

What is RAP usually?

Answer 15

2 mmHg

Question 16

If we increase TPR what happens?

Answer 16

• Afterload is increased so..
• CO goes down bc SV went down so..
• Venous return will go down
• There is no change in Mean systemic filling pressure though

Question 17

What will a decrease in TPR result in when looking at Venous return curve?

Answer 17

• Increased CO and SV
• Venous return will also increase (bc starling mechanism matches)
• No chang in MSFP
• Slope decreases

Question 18

What happens to Venous return and CO relationship with an increase in blood volume?

Answer 18

• Entire curve shifts up and to the right
• Higher preload so CO and SV goes up
• Venous return wil go up
• MSFP increases bc there is more blood

Question 19

When does a shift up and to the right on the CO and Venous return curve occur? (down and to left is opposite)

Answer 19

• Increased venous tone or venoconstriction

Question 20

What happens to Venous return and CO relationship with a decrease in BV?

Answer 20

• Decrease MSFP
• Shifts curve left and decreases venous return so curve shifts down and left

Question 21

What happens with an increase in contractility in regards to the Cardiac fxn and venous fxn curves?

Answer 21

• CO increases
• RA pressure decreases bc more blood is ejected
• New steady state is achieved