1) Physiology of Blood Cells and Haematological Terminology Flashcards

1
Q

What cells are derived from the multipotent myeloid precursor?

A

Megakaryocytes
Granulocyte-Monocyte
Erythroid

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2
Q

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

A

When they are immature they are more blue/purple

As they mature they become pinker

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3
Q

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

A

EPO is mainly produced in the kidneys by the juxtatubular interstitial cells

It is also produced to a lesser extent by the liver (hepatocyte and interstitial cells)

EPO production is stimulated by hypoxia

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4
Q

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

A

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

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5
Q

Define anisocytosis and poikilocytosis

A
Anisocytosis = red cells show more variation in SIZE than is normal 
Poikilocytosis = red cells show more variation in SHAPE than is normal
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6
Q

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

A

Lymphocytes are generally all the same size

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7
Q

Define hypochromia.

A

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

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8
Q

Define hyperchromia.

A

The red cells lack a central pallor

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9
Q

State two important types of hyperchromatic cells.

A

Spherocytes

Irregularly Contracted Cells

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10
Q

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

A

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

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11
Q

State a cause of spherocytosis.

A

Hereditary spherocytosis

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12
Q

What usually causes the formation of irregularly contracted cells?

What do they look like?

A

Oxidant damage to the cell membrane and haemoglobin

are irregular in outline
smaller than normal cells
have lost central pallor

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13
Q

Define polychromasia.

A

An increased blue tinge to the cytoplasm of a cell

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14
Q

What can reticulocytes be stained with?

A

Methylene blue

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15
Q

State six different types of poikilocytosis.

A
Spherocytes  
Elliptocytes 
Fragments 
Irregularly contracted cells  Target cells  
Sickle cells
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16
Q

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

A

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

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17
Q

State two causes of eliptocytosis.

A
Hereditary eliptocytosis  
Iron deficiency (also hypochromic)
18
Q

What biochemical phenomenon causes the sickling of red blood cells?

A

Polymerisation of haemoglobin S when present in a high concentration

19
Q

What is another name for fragments?

A

Schistocytes

20
Q

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

A

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

21
Q

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

A

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)

22
Q

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

A

G-CSF
M-CSF
GM-CSF
Interleukins

23
Q

How long do neutrophils survive for in the circulation?

A

7-10 hours

24
Q

What is the main role of eosinophils?

A

Parasitic infections

25
Q

Describe the shape of the nucleus of an eosinophil.

A

Eosinophils have a bilobed nucleus

26
Q

What is the main role of basophils?

A

They are involve in the allergic response

27
Q

Describe the appearance of basophils.

A

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

28
Q

Describe the appearance of monocytes.

A

They have a kidney bean shaped nucleus

They are large

29
Q

Other than phagocytosis, what is another role of macrophages?

A

They store and release iron

30
Q

How long do platelets survive for in the circulation?

A

10 days

31
Q

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

A

Leucocytosis

32
Q

What term is used to describe having too many platelets?

A

Thrombocytosis

33
Q

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

A

An atypical lymphocyte will have a large nucleus and a large amount of faint cytoplasm
This is typical of having a viral infection and is seen in glandular fever (infectious mononucleosis)

34
Q

What is ‘left shift’?

A

An increase in the number of non-segmented neutrophils or that there are 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 someone’s blood film has a lot of these band form nuclei then there has been a left shift

35
Q

What is toxic granulation? What can cause it?

A

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

36
Q

What is hypersegmentation of neutrophils? What can cause it?

A

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

37
Q

essential stem cell characteristics

A

ability to self renew and produce mature progeny

they divide into two cells with different characteristics, one another stem cell and the other a cell capable of differentiating to mature progeny

38
Q

neutrophil function

A
adhesion 
margination
rolling
diapedesis 
migration 
phagocytosis
39
Q

types of macrocytes

A

round
oval
polychromatic

40
Q

types of hyperchromia

A

spherocytes

irregularly contracted cells