Physiology of blood cells and haematological terminology

Question 1

What are all blood cells originally derived from?

Answer 1

multipotent haemopoietic stem cells.

Question 2

What do haemopoietic stem cells give rise to?

Answer 2

lymphoid stem cells and myeloid stem cells.

Question 3

What cells are derived from lymphoid and myeloid stem cells?

Answer 3

myeloid - megakaryocyte, granulocyte-monocyte, erythroid.

lymphoid - T, B cell, NK cell.

Question 4

Give an essential stem cell characteristic.

Answer 4

Ability to self renew and produce mature progeny by dividing into two cells with different characteristics - a stem cell and different cell.

Question 5

What pathway of differentiation gives rise to RBC?

Answer 5

myeloid stem cell –> proerythroblast –> erythroblasts –> RBC

Question 6

Where is erythropoietin produced?

Answer 6

90% juxtatubular interstitial cell in kidney, 10% hepatocyte and interstitial cells in liver.

Question 7

When is erythropoietin produced?

Answer 7

in response to hypoxia

Question 8

Outline the function and lifespan of a RBC.

Answer 8

survives 120 days in blood.

Transport O2 and some CO2.

Destroyed by phagocytic cells of spleen.

Question 9

What mediators are needed to allow differentiation and specialisation of haemopooietic stem cells to granulocytes and monocytes via myeloblasts and monoblasts?

Answer 9

Cytokines, e.g. G-CSF, M-CSF, GM-CSF.
Various interleukins.

Question 10

Outline the function and lifespan of a neutrophil.

Answer 10

survives 7-10 hours in blood before migrating to tissues.

Defence against infection - phagocytosis.

Question 11

What are the stages of neutrophil migration to tissues from blood?

Answer 11

Adhesion and margination.

Rolling.

Diapedesis.

Migration.

Question 12

What is the role of the eosinophil?

Answer 12

Defence against parasitic infection. Shorter lifespan in blood than neutrophil.

Question 13

What is the role of a basophil?

Answer 13

mediation of allergic responses.

Question 14

What is the role of the monocyte?

Answer 14

spend several days in circulation, migrate, then develop into macrophages with a phagocytic and scavenging function.
Store and release iron.

Question 15

How long to platelets survive in circulation?

Answer 15

10 days

Question 16

What is the role of platelets?

Answer 16

primary haemostasis

contribution of phosphlipids which promote blood coagulation.

Question 17

Outline the circulation pattern of a lymphocyte.

Answer 17

Recirculate to lymph nodes and other tissues then back to the blood stream.

Question 18

What is the lifespan of a lymphocyte?

Answer 18

very variable.

Question 19

Define anisocytosis and poikilocytosis.

Answer 19

Anisocytosis - red cells show more variation in size than normal

poikilocytosis - red cells show more variation in shape than normal

Question 20

What is the difference between micro and macrocytosis?

Answer 20

microcytosis - red cells smaller than normal.

Vice versa.

Question 21

What is the difference between a macrocytes and microcyte.

Answer 21

microcyte - red cell smaller than normal.

vice versa.

Question 22

Name 3 types of macrocytes.

Answer 22

• round macrocytes
• oval macrocytes
• polychromatic macrocytes.

Question 23

What is hypochromia, what causes it?

Answer 23

normal red cells have 1/3 of diameter that is pale.

Due to biconcave disk shape - centre has less haemoglobin and so is paler.

(hypochromia and microcytosis often seen together)

Question 24

Define hyperchromia. What might cause it?

Answer 24

Cells lack central pallor.

Can be caused by increased thickness of abnormal shape.

Question 25

Give 2 types of hyperchromic cells.

Answer 25

spherocytes, irregularly contracted cells.

Question 26

What causes spherocytosis?

Answer 26

Normally hereditary.

Question 27

What is spherocytosis?

Answer 27

cells are spherical in shape with round, regular outline and no central pallor. Due to loss of cell mebrane without loss of cytoplasm to cell rounds up.

Question 28

Describe and explain what causes irregular contracted cells.

Answer 28

Irregularly contracted cells - irregular in outline. Smaller than normal, lost their central pallor. Usually result of oxidant damage to cell membrane and haemoglobin.

Question 29

What is polychromasia?

Answer 29

Describes an increased tinge to the cytoplasm of red cell - indicating the cell is young.

Question 30

Jow does reticulocyte staining work?

Answer 30

exposes living RBC to new methylene blue which precipitates as a reticulum.

Question 31

Compare polychromia and reticulocyte staining.

Answer 31

Reticulocytes are easier to identify so can be counted more easily.

Question 32

Name some poikilocyte types.

Answer 32

Spherocytes Irregularly contracted cells Sickle cells Target cells Elliptocytes Fragments

Question 33

What are target cells? Why might they occur?

Answer 33

Cells with accumulation of haemoglobin in centre. Occur in obstructive jaundice, liver disease, haemoglobinopathies, hyposplenism.

Question 34

What are elliptocytes, when do they occur?

Answer 34

Elliptical in shape. Occur inhereditary elliptocytosis and iron deficiency.

Question 35

What are sickle cells? What causes them to occur?

Answer 35

Sickle or crescent shaped cells. Result from polymerisation of haemoglobin S when it is present in a high concentration.

Question 36

What are cell fragments?

Answer 36

small pieces of RBC (schistocytes).

Question 37

What is rouleaux? What causes it?

Answer 37

Stacks of RBC resembling a coin stack. Result from PP alteration.

Question 38

What are red cell agglutinates? What causes them?

Answer 38

Irregular clumps of RBC. Resut from antibodies binding to RBC cell surfaces.

Question 39

What is a Howell-Jolly body? What causes it?

Answer 39

A nuclear remnan in a red cell. Normally caused by impaired splenic function.

Question 40

Define leucytosis, leucopenia, neutrophilia, neutropenia, lymphocytosis, eosinophilia.

Answer 40

Leucocytosis — too many white cells Leucopenia — too few white cells Neutrophilia — too many neutrophils Neutropenia — too few neutrophils Lymphocytosis — too many lymphocytes Eosinophilia — too many eosinophils

Question 41

What is an atypical lymphocyte? When do they occur?

Answer 41

An abnormal lymphocyte. Present in infectious mononucleosis (glandular fever).

Question 42

Define left shift.

Answer 42

Increase in non-segmented neutrophils or there are neutrophil precursors in blood.

Question 43

What is toxic granulation? What causes it?

Answer 43

Heavy granulation of neutrophils. Results from infection, inflammation and tissue necrosis.

Question 44

What is neutrophil hypersegmentation? What causes it?

Answer 44

Increase in number of neutrophil lobes. Cased by lack of Vitamin B12 or folic acid.