HAEM - WBC Flashcards
Origin of blood cells barring the lymphocytes
Common myeloid progenitor -> myeloblast -> forms your granulocytes (basophil/neutrophil/eosinophil) and MONOCYTE (this is what goes on to form your macrophage)
What types of cells do myeloblasts give rise to?
Granulocytes (neutrophils/basophils/eosinophils) and monocytes
Granulocytes characteristic
They have granules present in the cytoplasm that contains agents essential for their microbicidal (something that kills microbes) function
What controls proliferation/survival of myeloid cells?
Myeloid growth factors such as G-CSF/M-CSF and GM-CSF (granulocyte-macrophage colony stimulating factor)
Eosinophil staining?
They are that reddish colour - that all arises from the granules in the cell
Basophils
Alkali - stain is very dark blue ; can barely see the nucleus
Neutrophils
Neutrally charged ; granules are a neutral colour
What can the colony stimulating factors be used for?
As drugs (in chemotherapy to recover the immune system for example)
Staging process ; normal granulocyte maturation
Myeloblast to promyelocytes into myelocytes to form a band form and neutrophils
Nucleus is lobulated - connected by fine filaments
Where does cell division occur in maturation?
Myeloblasts promyelocytes and myelocytes but NOT in metamyelocytes or band forms
Normaloblasts?
Erethrocytes
Neutrophil role?
survives 7-10 hours in circulation and the nucleus itself is segmented/lobulated ; main function is to phagocytose and kill micro-organisms
Neutrophil migration
Chemotaxis ; neutrophils become marginated in the vessel lumen and adhere to the endothelium migrating into tissues ; phagocytosis of micro-organisms occurs following cytokine priming
Sequence of events in chemotaxis?
Adhere + margination
Rolling
Diapedesis
Migration
Phagocytosis
Eosinophil
Spend less time in circulation than neutrophils ; main function is to defend against parasites
Why else are eosinophils important?
Regulation of Type 1 hypersensitivity reactions ; inactive the histamine and leukotrienes released by basophils/mast cells
INCREASE IN MAST CELLS = INCREASE IN EOSINOPHILS = INCREASE IN BASOPHILS
Basophils
Granules contain stores of histamine + heparin and proteolytic enzymes ; basic pH ; dark dark blue/purple
Mast cells vs basophils
Mast cells are same as basophils but reside in tissue rather than circulation
Basophil function
Modulation of inflammatory responses and mediation of immediate-type hypersensitivity reactions
Monocytes
Bloodstream equivalent of macrophages ; circulate for time and involved in phagocytosis
When monocytes migrate into tissues?
They become macrophages
Macrophages are involved in
Storing and releasing iron
How long do monocytes stay in circulation for?
Several days in circulation
Monocyte functions
Phagocytosis of micro-organisms as well as antigen presentation to lymphoid and other immune cells
Plasma cells description
Got this bluish basophilic circumference ; bluish colour is protein (ribosomes which stain bluish colour) ; because these cells are really busy building antigens
Normal lymphocyte appearance?
Quite small and a dense nucleus
B lymphocytes originate then developed in in?
Fetal liver and bone marrow originate
Development is just Ig heavy and light chain gene rearrangement leading to production of surface Igs against MANY DIFFERENT antigens (HUMORAL)
Then how are B cells narrowed down?
They are exposed to antigens in lymphoid tissue/nodes which results in recognition of non-self antigens by mature B cells and production of specific Igs
T lymphocytes formation
Progenitors migrate from fetal liver to thymus leading to development of T lymphocytes ; involved in cell-mediated immunity
NK cells can
kill tumour/virus-infected cells ; they are part of innate immune system
How can you identify gender of a patient by looking at a neutrophil?
In the nucleus - there is a small protrusion which is an X chromosome that has been pushed out
Reactive lymphocytes?
Usually associated with viral illnesses; they do not have the regular circular shape more plasmolysed ; irregular cytoplasm
Transient leukocytosis
Reactive cause and occurs when a a normal or health bone marrow responds to an external stimulus such as infection/inflammation/infarction
Persistent leukocytosis
Primary blood cell disorder ; not responsive but autonomous ; could be due to somatic DNA damage affecting precursors giving rise to leukaemia/lymphomas/myelomas
Leukocytosis
Broad term for an elevated WBC count
Term given for too many WBCs
Ends in ilia or cytosis
Term for reduced WBC count
Ends in penia (neutropenia/lymphopenia)
What is the most common cause of leukocytosis/leukopenia?
Changes in the neutrophil count since this is usually the most abundant leukocyte in circulation
Neutrophilia - when is it seen?
Pregnancy/or following exercise/after prescribing corticosteroids
Why does exercise cause neutrophilia?
Because vast majority of neutrophils are sat in vasculature
What is neutrophilia associated with?
Toxic granulation ; heavy coarse granulation of neutrophils and left shift (when IMMATURE neutrophils are released in response to an infection)
Example of myeloproliferative disorder
Chronic myeloid leukaemia - associated with neutrophilia + basophilia
Neutropenia causes
Chemo/radio or from autoimmune disorders/severe bacterial + viral + drugs like antimalarials/antipsychotic
Physiological basis of neutropenia
People of African descent
What do patients with neutropenia need?
Urgent treatment with intravenous antibiotics
When does a hypersegmented neutrophil occur?
Increase in the number of neutrophil lobes - RIGHT SHIFT ; results from a lack of vitamin B12/folic acid (megaloblastic anaemia)
How many lobes should a neutrophil usually have?
3 to 5
Eosinophilia
Allergy or parasitic infection ; can occur in CML too
Basophilia
Usually due to leukaemia
Monocytosis
Due to infection/chronic inflammation and present in some types of leukaemia
Lymphocytosis
Response to viral infection and can result from CML ; often pertussis infections
Lymphopenia
Les than 10^9/l ; often due to chemo/radio/HIV/corticosteroids
What are the most common lymphocytes in blood?
CD4+ T cells
Why does leukaemia occur?
Somatic mutations occurring in a primitive cell ; gives rise to its own clones that replaces normal cells + failure of apoptosis
Where are mutations present for leukaemia?
In oncogenes/tumour suppressor genes
Granulocyte maturation
Different stages
Granulocyte maturation
Different stages
