Haemodynamics and heart anatomy

Question 1

What is normal streamlined flow of blood called?

Answer 1

Laminar flow

Question 2

What does serum consist of? What does plasma consist of?

Answer 2

Plasma is fluid from blood including clotting factors. Serum is fluid from clotted blood (plasma minus clotting factors)

Question 3

What can cause turbulent flow?

Answer 3

Rate of blood flow too great, passes obstruction in vessel, makes a sharp turn, passes over a rough surface, ressistance to flow increases

Question 4

What is the differance between flow and velocity?

Answer 4

Flow is a rate- takes into account volume in a certain time

Velocity is a speed- distance traveled by blood in a time

Question 5

When there is a stenosis, what will happen to the velocity, flow and energy of the blood after the narrowing?

Answer 5

Velocity increases (blood pushed through at higher pressure), Flow decreases (less blood flowing through after stenosis) and energy increases ( E= 0.5 x mass (smaller) x Velocity (larger) squared

Question 6

What would be the result of two stenosis in the same vessel?

Answer 6

Marked decrease in blood flow so reduced perfusion leading to ishaemia

Question 7

How would mean systolic pressure be calculated from a pulse pressure graph?

Answer 7

Integrate area under a single peak (a single peak= a single pulse)

Question 8

How is pulse pressure calculated?

Answer 8

Peak systolic pressure- end diastolic pressure
Peak systolic is usually 120
End diastolic usually 80
120-80= 40 mmHg

Question 9

How can mean arterial pressure be estimated?

Answer 9

Diastolic pressure + 1/3 of pulse pressure

Question 10

Given a blood pressure of 140/ 80 mmHg. Calculate the pulse pressure and mean arterial pressure.

Answer 10

Pulse pressure= 140- 80= 60mmHg

Mean arterial pressure= 80+ (1/3x 60)= 100mmHg

Question 11

What is retrograde flow? When does it occur?

Answer 11

backwards flow of blood

can occur in arterial system when peripheral resistance is very high

Question 12

What is felt when we feel a pulse?

Answer 12

the shock wave that arrives slightly before the blood itself.

Question 13

What determines the strength or ‘volume’ of the pulse?

Answer 13

• The force the ventricle can eject the blood with to create a shock wave (reduced by valve stenosis, left V failure, hypovolaemia)- makes pulse thready
• The pulse pressure (more diastole means greater difference in pressures means stronger feel to pulse- bounding pulse)

Question 14

What can cause a bounding pulse?

Answer 14

• Bradycardia (more diastole)
• Low peripheral resistance (after hot bath, exercise, pregnancy) will also lower diastolic pressure so increases pulse pressure

Question 15

What is the name for excess fluid in the pericardium leading to compression of the heart?

Answer 15

Cardiac tamponade

Question 16

Name the layers of present from outside of pericardium to endocardium

Answer 16

• Fibrous layer
• Parietal layer
• cavity
• Visceral layer
• Myocardium
• Endocardium

Question 17

What is the transverse pericardial sinus? What is its significance?

Answer 17

The space under the pericardium aeorta and pulmonary artery. you can put a clip here to stop blood flow in/ out the heart for a bypass

Question 18

What is the name of the process of removing excess fluid from the pericardium?

Answer 18

Pericardiocentesis