Physiology of blood cells and haematological terminology

Question 1

Describe the origin and the life cycle of an erythrocyte:

Answer 1

Begins as pluripotent haematopoietic stem cells in the bone marrow.

Then becomes a multipotent myleiod stem cell –> proerythroblast –> erythroblast –> erythrocyte

Note: blasts have a large nucleus and less cytoplasm.

Question 2

What two types of stem cells are there and what do they differentiate into?

Answer 2

Pluripotent myleiod stem cells - erythoids, megakaryocytes and granulocytes

Lymphoid stem cells - T cells, B cell and NK cells

Question 3

Where is erythropoeitin released from and in response to what?

Answer 3

95% the kidneys - juxtatubular interstilitial cells
5% the liver.

Released in response to hypoxia.

Question 4

Describe a RBC:

Answer 4

lifespan 120 days

No nucleus - has an extensive cytoskeleton which allows it to be flexible and fit through small holes in capillaries.

Destroyed in the spleen by phagocytic cells - the older they get the less flexible so cannot squeeze past the wall of the spleen

Transports oxygen and carbon dioxide

Question 5

What is anisocytosis?

Answer 5

RBC shows a greater variation in size than is normal.

Question 6

What is pokiliocytosis?

Answer 6

RBC show more variation in shape than is normal.

Question 7

What is microcytosis?

Answer 7

Smaller than normal RBC

Question 8

What is macrocytosis?

Answer 8

Larger than normal RBC - compare their size to that of a lymphocyte

Question 9

What is hypochromatic RBC?

Answer 9

This is when there is a larger area than normal of central pallor; this should only be 1/3 of the cell. This leads to a flatter cell as there is less haemoglobin.

Question 10

What is hyperchromatic RBC?

Answer 10

This has no central pallor. This is due to them being thicker than normal or an abnormal shape.

Question 11

What are the two main types of hyperchromatic cells?

Answer 11

Spherocytes - this is round and has regular outline - result from a loss of cell membrane
Irregularly contracted cells - this will not be a complete circle, smaller than normal cells - usually due to oxidant damage

Question 12

What is rouleaux?

Answer 12

This is when the RBC stack up like a pile of coins due to alterations in the plasma proteins.

Question 13

What is agglutinates?

Answer 13

This is when the RBC clump up not in a tidy stack like roulauex due to the antibodies on their surface making them adhere.

Question 14

What is a howell jolly body?

Answer 14

This has a dot in the corner and this is a remnant of the nuclear material. This shows that there is some splenic failure and the spleen should remove all nuclear material

Question 15

What is a target cell?

Answer 15

This is a pokiliocyte that has the haemoglobin accumulating in the middle of the cell. 
It is due to:
-Obstructive jaundice failure
- liver disease
- Haemoglobinopathies
- Hyposplenism

Question 16

What is elliptocytes?

Answer 16

This is an elliptic shaped RBC.
Occur in:
-Hereditary elliptocytosis
-Iron deficiency

Question 17

What is sickle cell?

Answer 17

this is sickle shaped cells due to the polymerisation of a large concentration of the haemoglobin s chains.

Question 18

What is polychromasia?

Answer 18

This is when the blue -methyelene blue dye is retained . This shows that this is a young RBC - a reticulocyte.

Question 19

What are the different types of pokiliocytosis?

Answer 19

Spherocytes
irregularly contracted cells 
sickle cells
target cells 
ellipocytes 
fragments

Question 20

What are fragments?

Answer 20

They don’t look like full cells
A.K.A schistocytes
Cells are defective or due to abnormal stress.

Question 21

What is the formation of white blood cells?

Answer 21

myeloblast –> granulocytes –> specialised cells

Needs interleukin and cytokines.

Large nucleus; little cytoplasm

Question 22

Describe neutrophils:

Answer 22

7-10 hours in circulation

Defence against infection

Phagocytosis and kills microorganisms.

Multi-lobed nuclei

Question 23

Describe eosinophils:

Answer 23

Less time in circulation than neutrophils

Defence against parasitic infections

Two lobes in the nucleus

Question 24

Describe basophils:

Answer 24

Involved in allergic responses

Dark blue dots - do not see nucleus

Question 25

Describe monocytes:

Answer 25

Several days in the circulation

Large cells with a kidney bean shaped nucleus

Migrate to tissues where they become macrophages

Also store and release iron.

Question 26

Describe platelets:

Answer 26

Platelets are derived from megakaryocytes.

Survive 10 days in the circulation

Primary role in homeostasis.

Question 27

Describe lymphocytes:

Answer 27

Recirculate in the lymph and back to the blood stream.

Involved in defence and give rise to T, B and NK cells.

Question 28

What does cytosis/philia show?

Answer 28

Too many of a thing

Question 29

What does penia show?

Answer 29

Too few of a thing

Question 30

Which WBC’s shape is of interest?

Answer 30

Lymphocytes as these are usually the same.

They usually have a large nucleus and a small cytoplasm.

Question 31

What is left shift?

Answer 31

This is when there is an increase in non-segmented neutrophils or neutrophil precursors in the blood.

Question 32

What is toxic granulation?

Answer 32

Heavy granulation of neutrophils due to infection, inflammation and tissue necrosis.

Also a feature of normal pregnancy/

Question 33

What is a hyper segmented neutrophil?

Answer 33

Increase in the average number of neutrophil lobes or segments.

Usually due to a lack of B12 or folic acid