1 - Physiology of blood cells and haematological terminology

Question 1

What are all blood cells ultimately derived from?

Answer 1

Pluripotent haematopoietic stem cells

Question 2

What two lineages can pluripotent haematopoietic stem cells give rise to?

Answer 2

Lymphoid

Myeloid

Question 3

What cells are derived from the multipotent myeloid precursor?

Answer 3

Megakaryocytes
Granulocyte-Monocyte
Erythroid

Question 4

What cells are derived from the multipotent lymphoid precursor?

Answer 4

T cells
B cells
NK cells

Question 5

Give the steps from multipoint myeloid stem cell to erythrocytes

Answer 5

multipotent myeloid stem cell —–> proerythroblasts —–> erythroblasts —–> erythrocytes

Question 6

What are some common features of blasts?

Answer 6

They have a large nucleus and a small amount of cytoplasm

Question 7

How does the colour of red cells change as they mature?

Answer 7

When they are immature they are more blue/purple

As they mature they become pinker

Question 8

what does _blast refer to?

Answer 8

a precursor

Question 9

Which cells produce (erythropoietin) EPO? What can trigger the production of EPO?

Answer 9

EPO is mainly produced in the kidneys by the juxtatubular interstitial cells
It is also produced to a lesser extent by the liver
EPO production is stimulated by hypoxia

Question 10

What is erythropoesis?

Answer 10

the process of producing red blood cells

Question 11

What is erythropoietin?

Answer 11

a hormone secreted by the kidneys that increases the rate of production of red blood cells in response to falling levels of oxygen in the tissues

Question 12

What is the life span of a red blood cell?

Answer 12

120 days

Question 13

Define anisocytosis

Answer 13

red cells show more variation in SIZE than is normal

Question 14

Define poikilocytosis

Answer 14

red cells show more variation in SHAPE than is normal

Question 15

What can be used as a reference in a blood film to determine whether the red blood cells are microcytic or macrocytic?

Answer 15

Lymphocytes are generally all the same size

normally a red cell is bit smaller than a lymphocyte

Question 16

Define hypochromia.

Answer 16

The red cells have a larger area of central pallor than normal (paler than normal)
NOTE: normal red cells have a central pallor that covers around 1/3 of the red cell diameter

NOTE: hypochromia and microcytosis tend to go together

Question 17

Define hyperchromia.

Answer 17

The red cells lack a central pallor

Question 18

What may cause hyperchromia?

Answer 18

cells shape is thicker than normal or abnormal

Question 19

State two important types of hyperchromatic cells.

Answer 19

Spherocytes

Irregularly Contracted Cells

Question 20

What is responsible for the round shape of the spherocytes in spherocytosis?

Answer 20

It is caused by a loss of cell membrane that is not accompanied by an equivalent loss of cytoplasm

Question 21

State a genetic cause causing spherocytes

Answer 21

Hereditary spherocytosis

Question 22

What usually causes the formation of irregularly contracted cells?

Answer 22

Oxidant damage

Question 23

Define polychromasia.

Answer 23

An increased blue tinge to the cytoplasm of a cell

Question 24

What are reticulocytes?

Answer 24

red blood cells that are slightly younger than the mature RBCs

Question 25

What can reticulocytes be stained with?

Answer 25

Methylene blue

Question 26

State six different types of poikilocytosis.

Answer 26

``` Spherocytes Elliptocytes Fragments Irregularly contracted cells Target cells Sickle cells ```

Question 27

What are target cells? State some causes of target cells in the blood film.

Answer 27

Target cells have an accumulation of haemoglobin in the middle of the central pallor It is caused by obstructive jaundice, hyposplenism, liver disease, haemoglobinopathies

Question 28

State two causes of eliptocytosis. How can you differentiate between them under a microscope?

Answer 28

- Hereditary eliptocytosis - ----> nothing wrong with haemoglobin production and hence colour - Iron deficiency - ----> can't produce haemoglobin so will appear as hypochromic

Question 29

What biochemical phenomenon causes the sickling of red blood cells?

Answer 29

Polymerisation of haemoglobin S when present in a high concentration

Question 30

What is another name for fragments?

Answer 30

Schistocytes

Question 31

What is the appearance of fragments?

Answer 31

don't look like full cells small pieces of red blood cells will have a red colour and a central parlour, it is just the shape that is different

Question 32

State two different ways in which red blood cells can clump together and describe why they happen.

Answer 32

Rouleaux – like a stack of coins – it is cased by a change in plasma proteins pushing the red cells together Agglutinates – irregular clumps – caused by antibodies on the cell surface making the cells stick together

Question 33

What is a Howell-Jolly Body and what is it usually caused by?

Answer 33

This is a nuclear remnant in the red cells (very precise dot) This is most commonly caused by a lack of splenic function (the spleen should remove these tiny bits of nuclear material)

Question 34

Which cytokines are important in the differentiation of myeloblasts to granulocytes and monocytes?

Answer 34

G-CSF M-CSF GM-CSF

Question 35

Describe the appearance of myeloblasts

Answer 35

large nucleus and little cytoplasm (like pro erythroblasts)

Question 36

How long do neutrophils survive for in the circulation?

Answer 36

7-10 hours

Question 37

Describe the appearance of a neutrophil

Answer 37

segmented nucleus | lots of granules

Question 38

What is the main role of neutrophils?

Answer 38

defence against infection - phagocytoses and kills microorganisms

Question 39

What is the main role of eosinophils?

Answer 39

Parasitic infections

Question 40

Describe the shape of the nucleus of an eosinophil.

Answer 40

Eosinophils have a bilobed nucleus

Question 41

What is the main role of basophils?

Answer 41

They are involve in the allergic response

Question 42

Describe the appearance of basophils.

Answer 42

They have lots of dark blue dots in the cytoplasm (granules) | Often there are so many that you can’t even see the nucleus

Question 43

Describe the appearance of monocytes.

Answer 43

They have a kidney bean shaped nucleus | They are large

Question 44

Other than phagocytosis, what is another role of macrophages?

Answer 44

They store and release iron

Question 45

How long do platelets survive for in the circulation?

Answer 45

10 days

Question 46

What term is used to describe having too many white blood cells?

Answer 46

Leucocytosis

Question 47

What term is used to describe having too many platelets?

Answer 47

Thrombocytosis

Question 48

What is meant by leucopenia?

Answer 48

top few white cells

Question 49

What is meant by neutropenia?

Answer 49

too few neutrophils

Question 50

What term is used to describe a decrease in the number of lymphocytes?

Answer 50

lymphopenia

Question 51

What is the normal appearance of a lymphocyte?

Answer 51

normally small and round with a large nucleus and little cytoplasm

Question 52

Describe the appearance of an atypical lymphocyte. What can cause these to appear in a blood film?

Answer 52

An atypical lymphocyte will have a large nucleus and a LARGE AMOUT OF FAINT CYTOPLASM This is typical of having a viral infection and is seen in glandular fever (infectious mononucleosis)

Question 53

What is ‘left shift’?

Answer 53

An increase in the number of non-segmented neutrophils or having a lot of neutrophil precursors in the blood One of the first steps in segmenting is that it becomes a slightly more squashed looking nucleus that has more of a band shape If the blood film has a lot of band form nuclei = LEFT SHIFT

Question 54

What does left shift suggest?

Answer 54

you are fighting an infection because the bone marrow is producing lots of lymphocytes

Question 55

What is toxic granulation? What can cause it?

Answer 55

This is the heavy/dense granulation of neutrophils It results from infection, inflammation and tissue necrosis It is also a feature of normal pregnancy

Question 56

What is hypersegmentation of neutrophils? What can cause it?

Answer 56

An increase in the average number of neutrophil lobes or segments It usually relies on a lack of Vitamin B12 or folic acid

Question 57

What are erythrocytes?

Answer 57

red blood cells

Question 58

What is a granulocyte?

Answer 58

a white blood cell with secretory granules in its cytoplasm, e.g. an eosinophil or a basophil.

Question 59

What are megakaryocytes?

Answer 59

cells responsible for the production of platelets (thrombocytes)