Lecture 8: Blood Pressure And Cardiac Loads

Question 1

What is pulse pressure?

Answer 1

SBP - DBP

Question 2

What are the formulas for MAP?

Answer 2

DBP + 1/3 PP

2/3 DBP + 1/3 SBP

CO x SVR

Question 3

____________ and ________________ set the MAP

Answer 3

Cardiac output and systemic vascular resistance

Question 4

MAP sets the ____________________ and controls _______

Answer 4

Average driving pressure and controls flow

Question 5

What do the baroreceptors measure?

Answer 5

MAP and PP

SBP and DBP are not directly controlled or measured

Question 6

Pulse Pressure is directly proportional to _________ and _____________

Answer 6

Stroke volume and vascular stiffness

Increase stiffness => increase PP

Question 7

What factors affect the stroke volume?

Answer 7

Frank Straling law
Venous return
Ionotropic drugs or effectors

Question 8

What is a pre-load?

Answer 8

Tension on the muscle before it contracts ~ End Diastolic pressure

Question 9

What is an after-load?

Answer 9

The load the muscle contracts against ~ the pressure in the vessel leaving the heart

Question 10

If the muscle has to contract against an afterload is will contract _________ until it generates enough force to overcome the load

Answer 10

isometrically

Question 11

The after load limits ______________. If the muscle is too _________ it can’t generate enough fore to overcome the load.

Answer 11

Muscle shortening

Too Short

Question 12

___________ sets the pre-load and cardiac diastolic fibre length. __________ sets the after-load and the systolic fibre length.

Answer 12

Venous Return

Mean Arterial Pressure

Question 13

At a fixed after-load, Increasing the pre-load __________ muscle shortening

Answer 13

increases muscle shortening

Question 14

At a fixed pre-load, increasing the afterload ___________ muscle shortening

Answer 14

decreases muscle shortening

Question 15

____________ contraction occurs when all the valves are closed at the start of systole

Answer 15

Isovolumetric contraction

Question 16

When does Cardiac filling stop?

Answer 16

When Ventricular Pressure = Central Venous Pressure

Question 17

Increasing the pre-load ___________ the stroke volume

Answer 17

increases

Question 18

Increasing venous pressure __________ end diastolic volume and __________ pre-load

Answer 18

Increases

Increases

Question 19

At constant pre- and after loads, ionotropic agents ___________________________.

Answer 19

Increase force and shortening

Question 20

How is stroke work calculated?

Answer 20

SV x (Ventricular SBP - Ventricular DBP)

Question 21

How is minute work calculated?

Answer 21

CO x (Arterial Pressure - Venous Pressure)

Question 22

Increasing the volume of blood pumped __________ the work done

Answer 22

Increases

Question 23

Increasing the pressure the heart pumps against _________ the work done

Answer 23

Increases