Haemodynamics

Question 1

What is plasma?

Answer 1

Fluid collected from unclotted blood

so it includes clotting factors

Question 2

What is serum?

Answer 2

Fluid collected from clotted blood

so it doesn’t include clotting factors

Question 3

What is the relationship between plasma and serum?

Answer 3

Serum = plasma - clotting factors

Question 4

What is blood flow?

Answer 4

Volume of blood per unit time through blood vessel

Question 5

What are the factors affecting blood flow?

Answer 5

Difference in blood pressure

Resistance

Question 6

What is blood pressure?

Answer 6

The force that is exerted on blood vessel walls by the blood

Question 7

How does difference in blood pressure affect blood flow?

Answer 7

The bigger the difference in blood pressure

the more the blood flow

Question 8

What direction of pressure does blood move in?

Answer 8

High pressure to low pressure

Question 9

How does resistance affect blood flow?

Answer 9

As resistance increases

blood flow decreases

Question 10

What is resistance?

Answer 10

Opposition to blood flow

Question 11

What are the factors affecting resistance?

Answer 11

Length of blood vessel

Radius of blood vessel

Blood viscosity

Question 12

How does the length of a blood vessel affect resistance?

Answer 12

As length of blood vessel increases

resistance increases

Question 13

How does the radius of a blood vessel affect resistance?

Answer 13

As radius of blood vessel increases

resistance decreases

Question 14

How does blood viscosity affect resistance?

Answer 14

As blood viscosity increases

resistance increases

Question 15

What is peripheral resistance?

Answer 15

Total opposition to blood flow

offered by all the systemic vasculature

Question 16

What is another term for total peripheral resistance?

Answer 16

Systemic vascular resistance

Question 17

What type of blood vessel is mostly responsible for peripheral resistance?

Answer 17

Arterioles

Question 18

How do arterioles change the peripheral resistance?

Answer 18

Vasoconstriction decreases their radius, which increases resistance

Vasodilation increases their radius, which decreases resistance

Question 19

What is meant by whole blood viscosity?

Answer 19

How thick the blood is

Question 20

What can cause a major increase in whole blood viscosity? Which is the most common cause?

Answer 20

Multiple myeloma - most common cause
Leukaemia
Thrombocythaemia
Polycythaemia

Question 21

What component of blood does multiple myeloma affect? How is it affected?

Answer 21

Plasma
increases plasma viscosity
by increased number of immunoglobulins

Question 22

What effect does an increase in whole blood viscosity have on blood in the peripheries? Why?

Answer 22

Sludging of blood in peripheries

as blood cools down in peripheries

Question 23

What can cause a minor increase in whole blood viscosity?

Answer 23

Increased levels of acute phase proteins

Question 24

What are three examples of acute phase proteins?

Answer 24

Complement proteins
C-reactive protein (CRP)
Fibrinogen

Question 25

What causes an increase in acute phase proteins?

Answer 25

Inflammation

Question 26

What are acute phase protein levels used to measure?

Answer 26

Inflammatory response

Question 27

Which acute phase protein in particular is used to measure the inflammatory response?

Answer 27

CRP

Question 28

What are the two types of blood flow?

Answer 28

Laminar flow Turbulent flow

Question 29

What is laminar flow?

Answer 29

Blood flowing in straight lines | remaining at same distance from vessel wall

Question 30

Where is blood velocity greatest in laminar flow? Why?

Answer 30

In centre of vessel | because blood at peripheries comes into contact with vessel wall, increased friction, resistance to blood flow

Question 31

What is turbulent blood flow?

Answer 31

Blood flowing in all directions in the vessel | mixing of blood within vessel

Question 32

What are the causes of turbulent blood flow?

Answer 32

Blood velocity is too large Blood passes over rough surface Blood passes stenosis or obstruction in vessel Blood passes a sharp turn

Question 33

What is meant by stenosis of a blood vessel? And obstruction?

Answer 33

Stenosis means narrowing of blood vessel Obstruction means complete blockage of blood vessel

Question 34

What is it called when turbulence can be felt in a blood vessel?

Answer 34

Thrill

Question 35

What is it called when turbulence can be heard in a blood vessel?

Answer 35

Bruit

Question 36

What is it called when turbulence can be heard over a heart valve?

Answer 36

Murmur

Question 37

What is blood velocity?

Answer 37

Speed of blood moving through blood vessel

Question 38

What are the units of blood velocity?

Answer 38

Distance/time

Question 39

What are the factors affecting blood velocity?

Answer 39

Blood flow Cross-sectional area of blood vessel

Question 40

How does blood flow affect blood velocity?

Answer 40

As blood flow increases | blood velocity increases

Question 41

How does cross-sectional area of a blood vessel affect blood velocity?

Answer 41

As cross-sectional area of blood vessel increases | blood velocity decreases

Question 42

How are blood flow and blood velocity affected distal to a stenosis? Why?

Answer 42

Stenosis decreases radius of blood vessel, which increases resistance, which decreases blood flow Stenosis decreases cross-sectional area of blood vessel, which increases blood velocity

Question 43

What blood vessel abnormality often forms distal to stenosis? What does it mean?

Answer 43

Aneurysm | refers to an abnormal dilation of a blood vessel

Question 44

Why do aneurysms often form distal to a stenosis?

Answer 44

High blood velocity pushes on blood vessel walls | pushes them apart

Question 45

How does systole affect blood velocity?

Answer 45

Causes rapid increase in blood velocity as heart ejects lots of blood followed by rapid decrease as heart ejects less blood

Question 46

How does diastole affect blood velocity?

Answer 46

Negative blood velocity | As blood enters peripheries, faces peripheral resistance, bounces back slightly