Physiology of Blood Cells and Haematological Terminology

Question 1

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

Answer 1

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

Question 2

What does polychromasia indicate about the cell

Answer 2

It is young

Question 3

Causes of target cells

Answer 3

It is caused by obstructive jaundice, hyposplenism, liver disease, haemoglobinopathies

Question 4

Define anisocytosis and poikilocytosis

Answer 4

Anisocytosis = red cells show more variation in SIZE than is normal 
Poikilocytosis = red cells show more variation in SHAPE than is normal

Question 5

What usually causes the formation of irregularly contracted cells?

Answer 5

Oxidant damage

Question 6

What is another name for fragments?

Answer 6

Schistocytes

Question 7

Define polychromasia.

Answer 7

An increased blue tinge to the cytoplasm of a cell

Question 8

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

Answer 8

Lymphocytes are generally all the same size

Question 9

State six different types of poikilocytosis.

Answer 9

Spherocytes  
Elliptocytes 
Fragments 
Irregularly contracted cells 
Target cells  
Sickle cells

Question 10

What cells are derived from the multipotent myeloid precursor?

Answer 10

Megakaryocytes
Granulocyte-Monocyte
Erythroid

Question 11

State two important types of hyperchromatic cells.

Answer 11

Spherocytes

Irregularly Contracted Cells

Question 12

How long do platelets survive for in the circulation?

Answer 12

10 days

Question 13

What are target cells?

Answer 13

Target cells have an accumulation of haemoglobin in the middle of the central pallor

Question 14

State a cause of spherocytosis.

Answer 14

Hereditary spherocytosis

Question 15

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

Answer 15

Rouleaux – like a stack of coins – it is caused 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 16

Describe the appearance of basophils.

Answer 16

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

Question 17

What biochemical phenomenon causes the sickling of red blood cells?

Answer 17

Polymerisation of haemoglobin S when present in a high concentration

Question 18

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

Answer 18

When they are immature they are more blue/purple

As they mature they become pinker

Question 19

What are all blood cells ultimate derived from?

Answer 19

Pluripotent haematopoietic stem cells

Question 20

What is the main role of basophils?

Answer 20

They are involve in the allergic response

Question 21

Describe the shape of the nucleus of an eosinophil.

Answer 21

Eosinophils have a bilobed nucleus

Question 22

How long do neutrophils survive for in the circulation?

Answer 22

7-10 hours

Question 23

What are some common features of blasts?

Answer 23

They have a large nucleus and a small amount of cytoplasm

Question 24

What cells are derived from the multipotent lymphoid precursor?

Answer 24

T cells
B cells
NK cells

Question 25

3 features of irregularly contracted cells

Answer 25

Irregular in outline
Smaller than normal
Lost their pallor

Question 26

Other than phagocytosis, what is another role of macrophages?

Answer 26

They store and release iron

Question 27

State two causes of eliptocytosis.

Answer 27

Hereditary eliptocytosis  
Iron deficiency (also hypochromic)

Question 28

What is the life span of a red blood cell?

Answer 28

120 days

Question 29

Define hypochromia.

Answer 29

The red cells have a larger area of central pallor 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 30

Which cells produce EPO? What can trigger the production of EPO?

Answer 30

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 and anaemia

Question 31

Describe the appearance of monocytes.

Answer 31

They have a kidney bean shaped nucleus

They are large

Question 32

What can reticulocytes be stained with?

Answer 32

Methylene blue

Question 33

What two lineages can this give rise to?

Answer 33

Lymphoid

Myeloid

Question 34

Define hyperchromia.

Answer 34

The red cells lack a central pallor

Question 35

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

Answer 35

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

Question 36

What is the main role of eosinophils?

Answer 36

Parasitic infections

Question 37

What feature allows red blood cells to wriggle through small holes in the capillaries in the spleen?

Answer 37

As they lack a nucleus, red blood cells have an extensive cytoskeleton meaning that it is very flexible and can fit through small gaps
As the cells get older, they becomes less flexible and less able to pass through the capillaries into the sinuses in the spleen
This means that they are more likely to be retained in the spleen and phagocytosed

Question 38

What is a Heinz body

Answer 38

Remnants of Hg outside of cell

Question 39

What causes a heinz body

Answer 39

G6P deficiency