Introduction to Blood

Question 1

What is blood?

Answer 1

The viscous fluid pumped around the body by the heart and vascular system

Question 2

Why is blood viscous and what increases viscosity?

Answer 2

It is viscous due to the presence of cells

High blood cell count increases viscosity

Question 3

What is the liquid component of the blood and what systems is it involved in?

Answer 3

Plasma

Involved in clotting and complement systems

Question 4

What is the total blood volume?

Answer 4

5 litres

Question 5

How much blood can be lost before a transfusion is needed?

Answer 5

10% of total blood volume

1 pint

Question 6

What is the role of the arteries in blood transport?

Answer 6

They transport oxygenated blood form the heart to organs/tissues

Question 7

What is the role of the veins in blood transport?

Answer 7

They transport deoxygenated blood from the organs/tissues back to the heart

Question 8

What are the exceptions to the artery/vein general rule?

Answer 8

The pulmonary artery carries deoxygenated blood to the lungs

The pulmonary vein carries oxygenated blood back to the heart

Question 9

How does the small diameter of the capillary benefit it?

Answer 9

It helps to maximise the exchange between the blood and tissue

Question 10

What structures make up the circulatory system?

Answer 10

The blood, the heart and the blood vessels

Question 11

What are the two components of the circulatory system?

Answer 11

Systemic and pulmonary

Question 12

What is pulmonary circulation?

Answer 12

The loop through the lungs in which blood is oxygenated

Question 13

What is systemic circulation?

Answer 13

The loop through the rest of the body to supply tissues with oxygenated blood

Question 14

Why is the circulatory system a ‘closed system’?

Answer 14

All of the blood is contained within blood vessels

Question 15

Where to oxygen and nutrients diffuse to when they leave the blood vessel?

Answer 15

They diffuse across the blood vessel wall and enter interstitial fluid

Interstitial fluid carries them to target cells

Question 16

How much blood is pumped by the heart each minute?

Answer 16

5 litres

whole volume of blood in the body

Question 17

What are the 7 main functions of the blood?

Answer 17

1. Hydration of tissues & organs
2. delivery of oxygen to tissues & organs
3. Provision of nutrients to tissues & organs
4. Fighting infection through the innate and adaptive immune responses
5. Control of body temperature and pH
6. Distribution of endocrine hormones
7. Prevent blood loss

Question 18

What is the most abundant blood cell and what is its function?

Answer 18

Erythrocyte

It transports oxygen

Question 19

What is the difference between endocrine and paracrine hormones?

Answer 19

Endocrine hormones are secreted by endocrine glands directly into the blood

Paracrine hormones are not secreted into the blood, they are secreted within the tissue

Question 20

How many different blood cells are there?

From what are they derived?

Answer 20

11 different blood cells

All blood cells are derived from the multipotential haematopoietic stem cell in the bone marrow

Question 21

What are the 2 lineages of the multipotential haematopoietic stem cell?

Answer 21

It will form either a myeloid or lymphoid cell

Question 22

Which cells arise from the common myeloid progenitor?

Answer 22

1. megakaryocyte
2. erythrocyte
3. mast cell
4. myeloblast

Question 23

What does the myeloblast give rise to?

Answer 23

1. basophil
2. eosinophil
3. neutrophil
4. monocyte
   (which gives rise to macrophages)

Question 24

What does the megakaryocyte give rise to?

Answer 24

Thrombocytes (platelets)

Question 25

Which cells does the common lymphoid progenitor give rise to?

Answer 25

1. Natural killer cell | 2. small lymphocyte which gives rise to T and B lymphocytes

Question 26

Which blood cells are found in the bone marrow?

Answer 26

1. multipotential haematopoietic stem cell 2. megakaryocyte 3. myeloid progenitor 4. lymphoid progenitor

Question 27

When does a monocyte turn into a macrophage?

Answer 27

A monocyte becomes a macrophage as soon as it enters a tissue

Question 28

What % of the blood volume is plasma? How does this vary between the sexes?

Answer 28

55% of the volume of the blood is plasma Men have more erythrocytes so have less plasma

Question 29

How are blood cells separated from plasma?

Answer 29

Centrifugation

Question 30

What would centrifuged blood look like?

Answer 30

RBCs form the bottom layer Thin layer of WBCs and platelets Plasma forms the top layer

Question 31

What are the 3 most abundant proteins in the blood plasma?

Answer 31

1. albumin (35-50 g/L) 2. immunoglobulins (15 g/L) 3. Fibrinogen (3-5 g/L)

Question 32

What is the difference between blood plasma and serum?

Answer 32

Serum is similar to plasma but it DOES NOT contain clotting factors

Question 33

How is blood serum obtained?

Answer 33

The blood serum is allowed to clot before it is centrifuged

Question 34

What are the equations for blood plasma and blood serum?

Answer 34

serum = plasma - clotting factors plasma = serum + clotting factors + clotting inhibitor

Question 35

What clotting inhibitor is added to blood plasma and why?

Answer 35

heparin or citrate it prevents the blood from clotting and the plasma becoming serum

Question 36

What happens if there is a transfusion of incompatible blood groups?

Answer 36

Antibodies react with antigens on the red blood cell membrane This causes haemolysis and the RBCs rupture

Question 37

What are blood groups?

Answer 37

They are a classification based on antigens present on the red blood cell membrane

Question 38

What is significant about blood groups and differences between populations?

Answer 38

There is a lot of ethnic diversity between blood groups

Question 39

What is the ABO blood grouping based on and what are the different blood types?

Answer 39

based on a carbohydrate antigen on the RBC plasma membrane A, B, AB and O

Question 40

How does prevalence of ABO blood types vary in Asia and Europe?

Answer 40

B is more prevalent in Asia A is more prevalent in Europe

Question 41

Which blood group is the "universal donor" and why?

Answer 41

O It has both the A and B antibodies present in the plasma It has no antigens on its surface so can be received by any blood type

Question 42

Which blood group is the "universal recipient" and why?

Answer 42

AB There are no antibodies in the blood, so it can receive any blood type

Question 43

In someone with type B blood, what antigens and antibodies are present?

Answer 43

They have B antigens on their plasma membrane There are antibodies against the A antigen in the blood

Question 44

What happens if someone with type A blood is given a transfusion with type B blood?

Answer 44

There are antibodies against the B antigen in the blood This leads to haemolysis

Question 45

When transfusing plasma, what blood type is the "universal donor"?

Answer 45

AB It contains no antibodies in the plasma

Question 46

When transfusing plasma, what blood type is the "universal recipient"?

Answer 46

O It can receive plasma containing any type of antibody as there are no antigens on the cell surface

Question 47

Why does haemolysis occur?

Answer 47

Due to incompatibility of blood types

Question 48

What are the 7 symptoms of haemolysis?

Answer 48

1. sensation of heat in the transfused vein 2. lumbar pain 3. hypotension and uncontrollable bleeding 4. systematic fever and chills 5. increase in heart rate 6. haemoglobinuria 7. hyperbilirubinemia

Question 49

What is haemoglobinuria? Why does this occur and why is it dangerous?

Answer 49

Haemoglobin present in the urine Haemolysis causes breakage of RBCs so the Hb concentration in the blood rises Hb is secreted in the urine which can lead to kidney failure

Question 50

What is hyperbilirubinemia?

Answer 50

Too much bilirubin in the blood

Question 51

What is the Rhesus blood group based on?

Answer 51

An ion-channel antigen on the RBC plasma membrane | This is the D-antigen or factor D

Question 52

What are the 2 blood groups in the Rhesus classification? How does their prevalence vary?

Answer 52

Rh+ Has the D-antigen and is more common Rh- Does not have the ion-channel and is more rare

Question 53

When does haemolytic disease of the newborn occur?

Answer 53

If a Rh- woman is pregnant with a Rh+ foetus

Question 54

How does haemolytic disease of the newborn arise?

Answer 54

during birth, some foetal blood mixes with the mother's blood Some D-antigen enters the mother's blood This starts an immune response against the D-antigen and leads to antibody production

Question 55

How does haemolysis arise in haemolytic disease of the newborn?

Answer 55

The antibodies against the D-antigen may cross the placental barrier and enter foetal circulation This causes haemolysis

Question 56

Why is haemolytic disease of the newborn more likely to affect a second pregnancy than a first?

Answer 56

There is usually enough separation of blood during the first pregnancy During the second, there are memory cells and a more rapid immune response

Question 57

What is meant by sensitisation?

Answer 57

Haemolytic syndrome may be caused by a previous pregnancy or amniocentesis

Question 58

What is aminocentesis?

Answer 58

Amniotic fluid is taken from the foetus Some of the foetal blood may come into contact with the mother's blood

Question 59

How is haemolytic syndrome treated?

Answer 59

Intramuscular injection with the Rh antigen at 28 weeks, 34 weeks and within 72 hours after delivery

Question 60

Why is the mother injected with D antigen?

Answer 60

This helps to mop up any antibodies that the mother has produced and prevent an immune response