White Blood Cells

Question 1

Where do white blood cells originate form?

Answer 1

Multi potent Haemopoietic stem cell —> myeloid
—> lymphoid

Question 2

What do granulocytes refer to?

Answer 2

Neutrophils

Basophils

Eosinophils

Question 3

Why are granulocytes called granulocytes?

Answer 3

Granules present in the cytoplasm

Con takin agents essential for their microbial function

Question 4

What growth factors are essential for the proliferation ands survival of myeloid cells?

Answer 4

G-CSF granulocyte colony-stimulating factor

M-CSF, macrophage colony-stimulating factor

GM-CSF, granulocyte-macrophage colony stimulating factor

Question 5

In what stage of maturation does cell division not occur?

Answer 5

Metamyelocytes

Band forms

Question 6

What is the main function of a neutrophil?

Answer 6

Defence against infection
—> phagocytoses and then kills micro-organisms

Granules contain enzymes that kill micro-organisms

Question 7

What is the nucleus like in a mature neutrophil?

Answer 7

Segmented (lobulated)

Question 8

What are the 2 mechanisms for phagocytosis of pathogens by neutrophils?

Answer 8

Superoxide dependent mechanism
—> release oxygen species called respiratory burst
—> provides substrate for myeloperoxidase
—> leads to production of toxic acidic substances

Oxygen independent mechanism
—> variety of anti-microbial against are released

Question 9

What is chemotaxis?

Answer 9

First step of neutrophil migration
- neutrophil marginated in the vessel lumen
- adhere to endothelium and migrate into tissues

Phagocytosis of pathogens occurs following cytokine priming

Question 10

What is the function of an eosinophil?

Answer 10

Main function in défense against parasitic infection

Important in the regulation if Type 1 hypersensitivity reactions
—> inactivate the histamine and leukotrienes released by basophils and mast cells

Question 11

What kind of nucleus do eosinophils have?

Answer 11

Bilobed nucleus

Question 12

What is the function of a basophil?

Answer 12

Variety of immune and inflammatory responses

Question 13

What do the granules of basophils contain?

Answer 13

Histamine

Heparin

Protéolytique enzymes

Question 14

What are the key roles of monocytes?

Answer 14

Phagocytosis of micro-organisms covered with antibody and complement

Phagocytosis of bacteria/fungi

Antigen presentation to lymphoid and other immune cells

Question 15

What do monocytes develop into?

Answer 15

Macrophages

They store and release iron

Question 16

What does the lymphoid stem cell give rise to?

Answer 16

T cells

B cells

Natural killer cells (NK)

Question 17

Where do lymphocytes go once made?

Answer 17

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

Question 18

Where do B lymphocytes originate?

Answer 18

Foetal liver

Bone marrow

Question 19

How do B lymphocytes mature?

Answer 19

Requires exposure to antigens in lymphoid tissue

Question 20

What do B lymphocytes do?

Answer 20

Involved in humoral immunity

Question 21

How do T cells develop?

Answer 21

Lymphocyte progenitors migrate from feral liver to the thymus
—> lead to development of T lymphocytes

Question 22

What do T lymphocytes do?

Answer 22

Involved in cell-mediated immunity

Question 23

What do NK cells do?

Answer 23

Part of innate immune system

Kill tumour cells and virus-infected cells

Question 24

What abnormalities can occur in white cells?

Answer 24

Numerical

Morphological

Both

Question 25

What is leukocytosis?

Answer 25

Too many white cells

Question 26

What is transient leukocytosis?

Answer 26

Leukocytosis frequently found in association with infection

Question 27

What is neutrophilia?

Answer 27

Too many neutrophils

Question 28

What causes neutrophilia?

Answer 28

Infection Inflammation Infarction/tissue damage Myeloproliferative disorders Pregnancy Following exercise —> rapid shift of neutrophils from marginated pool to circulating pool After using corticosteroids

Question 29

What may neutrophilia be accompanied with?

Answer 29

Toxic change Left shift

Question 30

What is left shift?

Answer 30

Increase in non-segmented neutrophils Or Neutrophils precursors in blood that should normally be in bone marrow

Question 31

What does left shift reflect?

Answer 31

Increased neutrophil production —> increased output from bone marrow —> churning out more immature versions of neutrophils

Question 32

What is eosinophilia?

Answer 32

Too many eosinophils

Question 33

What causes eosinophilia?

Answer 33

Usually due to: allergy/parasitic infection asthma/eczema/drugs

Question 34

What is basophilia?

Answer 34

Too many basophils

Question 35

What causes basophilia?

Answer 35

Usually due to leukaemia as it’s uncommon

Question 36

What is lymphocytosis?

Answer 36

Too many lymphocytes

Question 37

What causes lymphocytosis?

Answer 37

Viral infections in transient leukocytosis Lymphoproliferative disorder in persistent leukocytosis Whooping cough in children

Question 38

What is monocytosis?

Answer 38

Too many monocytes

Question 39

What causes monocytosis?

Answer 39

Infection Chronic inflammation Some leukaemia types

Question 40

What is persistent leukocytosis?

Answer 40

Leukocytosis that may be caused by leukaemia

Question 41

What is Chronic Myeloid Leukaemia (CML)?

Answer 41

Increase in all granulocytes ans their precursors in both blood and bone marrow

Question 42

What does CML result from?

Answer 42

Translocation between chromosome 9 and22 ina single HSC —> give rose to many mutated cells —> hence CML through colonial expansion

Question 43

What is the abnormally short chromosome 22 in CML called?

Answer 43

Philadelphia chromosome

Question 44

What symptoms can CML cause?

Answer 44

Enlarged spleen

Question 45

How can CML be treated?

Answer 45

Tyrosine inhibitors —> inhibit uncontrolled division

Question 46

What is Chronic Lymphocytic Leukaemia (CLL)?

Answer 46

Lymphoproliferative disorder

Question 47

What are the characteristics of CLL?

Answer 47

Squashed ‘smear’ or ‘smudge’ lymphocytes

Question 48

How can we determine the cause of lymphocytosis?

Answer 48

Characterising the profile of cell surface markers expressed by lymphocytes

Question 49

What is Acute Lymphoblastic Leukaemia?

Answer 49

Increase in very immature cells (lymphoblasts) with failure of these to develop into lymphocytes

Question 50

How is ALL caused?

Answer 50

Bone marrow is infiltrated by lymphoblasts —> results in impaired heamopoiesis —> lymphoblasts circulate in the peripheral blood

Question 51

What are the haematological features of ALL?

Answer 51

Leukocytosis of lymphoblasts Anaemia —> suppression of normal haemopoiesis Neutropenia Thrombocytopenia —> low platelet count Replacement of normal bone marrow cells by lymphoblasts

Question 52

What are clinical features of ALL?

Answer 52

Prominent bruising due to thrombocytopenia Pale skin as a result of anaemia

Question 53

Treatment of ALL?

Answer 53

Supportive therapy where there’s anaemia + thrombocytopenia and infection susceptibility: - red cell transfusions - platelet transfusions - antibiotics Systemic chemotherapy —> through the body Intrathecal chemotherapy —> through spine —> sanctuary for lymphocytes

Question 54

What is leukopenia?

Answer 54

Reduction in total number of white cells

Question 55

What is neutropenia?

Answer 55

Too few neutrophils

Question 56

What causes neutropenia?

Answer 56

Chemo/radiotherapy —> suppresses bone marrow activity Autoimmune disorders Physiological stuff —> ethnic heritage

Question 57

What is lymphopenia?

Answer 57

Too few lymphocytes

Question 58

What causes lymphopenia?

Answer 58

HIV infection Chemotherapy Radiotherapy Corticosteroids Severe infection may develop transient low lymphocyte count