Integration

Question 1

What is mean systemic filling pressure determined by

Answer 1

Blood volume

Question 2

How can venous return be increased or decreased

Answer 2

By changing the mean systemic filling pressure (blood volume) or by changing total peripheral resistance

Question 3

Describe the use of beta blockers in heart failure

Answer 3

Beta blockers are competitive antagonists for sympathetic NT epinephrine. They reduce the heart rate and force of contractility reducing the work load on the heart.

Question 4

Why would you use diuretics in heart failure

Answer 4

Reduce blood volume

Question 5

Why would you want to reduce blood volume in heart failure

Answer 5

To reduce the congestion and it’s associated symptoms (pulmonary and systemic oedema)

Question 6

Why do you use beta blockers in heart failure

Answer 6

In diastolic heart failure beta blockers are of use in that they slow the heart allowing for greater filling time increasing EDV and thus stoke volume (and thus cardiac output)

Question 7

What is venous return determined by

Answer 7

Right atrial pressure, blood volume, venous capacitance, systemic vascular resistance (if high impedes flow back to heart)

Question 8

Formula for venous return

Answer 8

VR= Pa (102mmHg)-Pv (2mmHg)/ resistance (20mmHg)= 5

Question 9

What is mean systemic filling pressure

Answer 9

When CO is nothing the arterial and venous pressures eventually equal in normal circumstances to 7mmHg which is the pressure on the vessels as a result of blood volume