Physiology of blood cells and haematological terminology

Question 1

Where do blood cells of all types originate?

Answer 1

In the bone marrow

Question 2

What are all blood cells ultimately derived from?

Answer 2

Pluripotent haematopoietic stem cells

Question 3

What do pluripotent haematopoietic stem cells give rise to?

Answer 3

Lymphoid stem cells

Multipotent myeloid stem cells/precursors

Question 4

What do erythrocytes originate from?

Answer 4

Multipotent haematopoietic stem cell –> multipotent myeloid stem cell/precursor –> proerythroblast –> erythroblast –> erythrocyte

Question 5

What are the functions of erythrocytes?

Answer 5

Oxygen transport

Some carbon dioxide transport

Question 6

What is the approximate intravascular life span of an erythrocyte?

Answer 6

120 days

Question 7

What do white cells originate from?

Answer 7

Multipotent haemopoietic stem cell –> multipotent myeloid stem cell/precursor –> myeloblast –> granulocytes, monocytes

Question 8

What do monocytes and granulocytes need for further differentiation?

Answer 8

Cytokines:
G-CSF - granulocyte colony stimulating factor
M-CSF - macrophage
GM-CSF
Various interleukins

Question 9

What is the approximate intravascular life span of a neutrophil?

Answer 9

7-10 hours

Question 10

What is the function of neutrophils?

Answer 10

Defence against infection

Phagocytoses and kills MOs

Question 11

What is the approximate intravascular life span of a eosinophil?

Answer 11

Less than 7 hours (less than a neutrophil)

Question 12

What is the function of eosinophils?

Answer 12

Defence against parasitic infection

Question 13

What is the approximate intravascular life span of a monocyte?

Answer 13

Several days

Question 14

What are the functions of monocytes?

Answer 14

Migrate into tissues and develop into macrophages and other specialised cell types w/phagocytic function
Store and release iron

Question 15

What is the approximate intravascular life span of a platelet?

Answer 15

10 days

Question 16

What are the functions of platelets?

Answer 16

Primary haemostasis

Contribute phospholipid in blood coagulation

Question 17

What do platelets originate from?

Answer 17

Multipotent haemopoietic stem cell –> multipotent myeloid stem cell/precursor –> megakaryocytes –> platelets

Question 18

What do lymphocytes originate from?

Answer 18

Multipotent haemopoietic stem cell –> lymphoid stem cell –> T, B, NK cells

Question 19

What is the approximate intravascular life span of a lymphocyte?

Answer 19

Very variable

Question 20

What is anisocytosis?

Answer 20

Red cells show more variation in size than is normal

Question 21

What is poikilocytosis?

Answer 21

Red cells show more variation in shape than is normal

Question 22

What is microcytosis?

Answer 22

Smaller red cells than normal or an anaemia with small red cells

Question 23

What is macrocytosis?

Answer 23

Larger red cells than normal or an anaemia with large red cells

Question 24

What is hypochromia? What causes it?

Answer 24

Cells have a larger area of central pallor than normal (normally 1/3 of diameter)

Lower haemoglobin content and concentration + flatter cell

Question 25

What is hyperchromia? What causes it?

Answer 25

Cells lack central pallor | Bc thicker than normal or shape is abnormal

Question 26

What are 2 important types of hyperchromic cells? What causes them?

Answer 26

Spherocytes - loss of CM w/o loss of equivalent amount of cytoplasm - hereditary spherocytosis Irregularly contracted cells - oxidant damage to CM and Hb

Question 27

What is polychromasia? What causes it?

Answer 27

Increased blue tinge to the cytoplasm of a red cell As red cells mature, they go from dark blue --> pink Indicates that red cells are young (reticulocytes) - not fully matured

Question 28

What shapes can red cells be?

Answer 28

``` Spherocyte Irregularly contracted cell Sickle cell Target cell Elliptocyte Fragment ```

Question 29

What are the differences between Rouleaux and agglutinates?

Answer 29

Rouleaux = neat stacks of red cells due to increased levels of plasma proteins Agglutinates = irregular clumps of red cells due to antibodies on cell surface

Question 30

What is Howell-Jolly body? What is the most common cause?

Answer 30

Nuclear remnant in a red cell Lack of splenic function Spleen should remove these tiny remaining bits of nuclear material

Question 31

What is a target cell? When do they occur?

Answer 31

Red cell with accumulation of haemoglobin in middle of central pallor Obstructive jaundice, liver disease, haemoglobinopathies, hyposplenism

Question 32

What is an elliptocyte? When do they occur?

Answer 32

Elliptical and hypochromic red cell | Hereditary elliptocytosis and iron deficiency

Question 33

What are fragments? What do they indicate?

Answer 33

AKA schistocytes Small pieces of red cells - tend to have red cell colour and central pallor, just shape is different Indicate fragmented red cells

Question 34

What is leucocytosis?

Answer 34

Too many white cells

Question 35

What is leucopenia?

Answer 35

Too few white cells

Question 36

What is neutrophilia?

Answer 36

Too many neutrophils (may be normal in infection)

Question 37

What is neutropenia?

Answer 37

Too few neutrophils

Question 38

What is lymphocytosis?

Answer 38

Too many lymphocytes

Question 39

What is eosinophilia?

Answer 39

Too many eosinophils

Question 40

What is thrombocytosis?

Answer 40

Too many platelets

Question 41

What is thrombocytopenia?

Answer 41

Too few platelets

Question 42

What is erythrocytosis?

Answer 42

Lots of red blood cells

Question 43

What is reticulocytosis?

Answer 43

Lots of reticulocytes

Question 44

What is lymphopenia?

Answer 44

Reduced number of lymphocytes

Question 45

What do lymphocytes typically look like?

Answer 45

Small and round Large nucleus Little cytoplasm

Question 46

What does an atypical lymphocyte typically look like?

Answer 46

Large and very visible nucleus Loads of really faint cytoplasm Note: typical of viral infection

Question 47

What is left shift? What does it suggest?

Answer 47

Increase in non-segmented neutrophils or presence of neutrophil precursors in the blood Band form neutrophils present in blood film Suggests infection or inflammation - BM releasing lymphocytes earlier than normal

Question 48

What is toxic granulation?

Answer 48

Heavy granulation of neutrophils due to infection, inflammation or tissue necrosis (or normal pregnancy)

Question 49

What is a hypersegmented neutrophil?

Answer 49

A neutrophil with an increased number of nucleus lobes or segments

Question 50

What are sickle cells? What is the cause?

Answer 50

Sickle/crescent shaped red cells due to polymerisation of HbS when present in high concentration