White Blood Cells Flashcards
What cells are granulocytes?
Basophils, Neutrophils, Eosinophils
They have granules in them
What gives rise to granulocytes
Multipotent haematopoietic stem cells give rise to myeloblasts
Myeloblasts can mature into any granulocyte as well as monocytes and macrophages
What is production of granulocytes controlled by?
Growth factors:
CSF= Colony stimulating factor
G-CSF= granulocyte colony stimulating factor
M-CSF= macrophage colony stimulating factor
GM-CSF= granulocyte-macrophage colony stimulating factor
What is the role of neutrophils and how long do they survive for?
Survive for 7-10 hours in circulation before going to tissues
Defend against infection by phagocytosis and killing microorganisms
How do neutrophils get to the site of inflammation?
Move to site of inflammation by chemotaxis- inflammatory mediators are released.
These have a gradient: neutrophils move to an area of high concentration of mediators
Neutrophils attach to endothelium of blood vessel and migrate into tissue where inflammation is
What are neutrophils exposed to?
Neutrophils are exposed to cytokines (inflammatory mediators) in a process called cytokine priming so they can start to phagocytose organisms
What do neutrophils look like?
2-5 uneven lobed of nucleus which are connected
How long do eosinophils spend in circulation in comparison to neutrophils?
less time than neutrophils
What is the role of eosinophils?
Defend against parasitic infection
What does an eosinophil look like?
2-3 connected equal size lobes
Cytoplasmic granules in bright pink
What is the role of basophils?
Role in allergic response and other immune/inflammatory response
What do basophil granules contain?
Histamine, Heparin and proteolytic enzymes
What gives rise to monocytes?
Myeloid stem cells give rise to monocyte precursors which give rise to monocytes
Monocytes are precursors of macrophages
How long do monocytes spend in circulation?
Several days
What do monocytes develop into?
Develop into macrophages and other specialised cells when they migrate into tissues
What is the function of monocytes?
Have phagocytic and scavenging function
Store and release iron
Present antigens to lymphoid cells i.e. B and T cells
What is leucopenia?
A reduction in white cells
What is neutropenia?
Too few neutrophils
What can cause neutropenia?
Can occur after chemotherapy and radiography
Can be a result of autoimmune disorders, severe bacterial infections, certain viral infections and some drugs e.g. anticonvulsants and antipsychotic drugs and some antimalarials
In what ethnicities is benign ethnic neutropenia normal in?
African or Afro-Caribbean
What are the consequences of a low neutrophil count?
increased risk of infection- needs urgent treatment with IV antibiotics
What is lymphopenia?
Too few lymphocytes
What are causes of lymphopenia?
HIV, chemotherapy, radiotherapy, steroids
Can also occur temporarily in severe infection
What gives rise to lymphocytes?
Lymphoid stem cells gives rise to T, B and NK cells
Where do lymphocytes circulate?
Circulate between lymph nodes, tissue and blood
How long do lymphocytes live for?
Lifespan varies
What do B lymphocytes mature into?
Plasma cells
What gives rise to B cells
Progenitor B cells give rise to pre B cells which give rise to mature B cells
What does maturation of B cells require?
Requires exposure to antigens in lymph nodes and lymph tissue- leads to production of specific Igs and antibodies
What is the role of T cells?
Involved in cell mediated immunity
What happens when T cells mature?
T cell develops CD4 and CD8 cell surface markers
What are CD4+ cells?
They’re T helper cells. They produce cytokines and activate monocytic macrophage system and promote synthesis of antibodies
What are CD8+ cells?
There cytotoxic T cells. They destroy virus infected cells through binding of T cell receptor
What is the role of a natural killer cell?
Can kill tumour cells and virus infected cells
What is leukocytosis?
Too many white blood cells: includes neutrophilia, lymphocytosis, monocytosis, eosinophilia and basophilia
What is neutrophilia?
Too many neutrophils
What are causes of neutrophilia?
Infection, inflammation, tissue damage, myeloproliferative neoplasms (cancer of too many WBCs)
MITI
Where may neutrophilia be seen commonly?
In pregnant women after administration of corticosteroids
How can sudden neutrophilia be caused?
Marginal neutrophils attached to endothelium can go back into blood vessel. This may be accompanied with toxic changes and left shift
What is left shift?
increase in non-segmented neutrophils- more immature neutrophils in blood
What is toxic granulation?
Heavy granulation of neutrophils
What is eosinophilia?
Too many eosinophils
When does eosinophilia occur?
In parasitic infections and in allergy
In what conditions can eosinophilia occur?
Can occur is leukaemia, asthma and in response to drugs
What is basophilia?
Too many basophils
When might basophilia occur?
It is rare but may occur in leukaemia
What is monocytosis?
Too many monocytes
What causes monocytosis?
Infection, chronic inflammation, severe leukaemia
What is lymphocytosis?
Too many lymphocytes
Why does lymphocytosis occur?
May be a temporary response to viral infections- results in atypical lymphocytes
If chronic it can cause leukaemia CML
Mononucleosis (glandular fever) can cause it
Large irregular WBCs on blood film
Whats a common cause of lymphocytosis in kids?
Whooping cough (bordella petussis)
What do basophils look like?
Have blue cytoplasmic granules
Have a lobed nucleus
What does a monocyte look like?
Has an indented nucleus and pale granules in cytoplasm
What does a lymphocyte look like?
Small cells with a spherical nucleus and little cytoplasm
