The Scope of Clinical Haematology Flashcards
What are the components of blood?
- Plasma - coagulation factors, albumin, antibodies
- White cells and platelets
- Red blood cells
What are the main functions of blood?
Transport (nurtrients and waste products)
Preventage of leaks and blockages (clotting and fibrinolytic enzymes)
Protection from pathogens
What is the lifespan of a red blood cell? How is synthesis of new RBCs regulated?
About 120 days
Stimulated by erythropoietin, which is made in the kidney in response to hypoxia
What cell types differentiate into red blood cells? Number of which cell type is a good indicator of red cell production?
Erythroblast - Reticulocyte - Erythrocyte
Reticulocyte count is a good indicator of red cell production
What are the most common causes of anaemia?
Deficiency in haematinics:
- Iron
- Folate
- Vitamin B12
What is the lifespan of a platelet? What regulates the production of platelets?
- Lifespan of about 7 days
Production regulated by thrombopoietin, a hormone produced in the liver. Controlled by platelet mass feedback
What is the lifespan of neutrophils? What regulates their production?
Lifespan of 1-2 days
production in response to bacterial infections, mediated by interleukin-17
IL-17 induces the production of G-CSF (Granulocyte colony stimulating factor) which stimulates the production of neutrophils
How can G-CSF be used therapeutically?
In patients recieving chaemotherapy that kills off their neutrophils G-CSF may be given post treatment to stimulate neutrophil production in order to protect against infection
What are the functions of monocytes? What can they differentiate into?
To ingest and destroy pathogens, mostly bakcteria and fungi. (reticuloendothelial system)
Subset of monocytes migrate into cells and differentiate into macrophages and dendritic cells
Function of eosinophils? What issues are they often implicated in?
Protection against parasites
Often implicated in allergic reactions
Function of lymphocytes?
Adaptive immunity - immunological memory via surface antigens (CD markers) that recognize bacteria / fungi
What are the main subtypes of lymphocytes?
B cells - make antibodies
T cells - helper cells, cytotoxic and regulatory
NK cells
Where are B and T cells produced? Where do they mature?
Both produced in the bone marrow
B cells mature in the bone marrow
T cells mature in the thymus
What are the characteristics of antigen receptors on the surface of lymphocytes?
All contain a constant and a variable part
Variable part accounts for the ability to detect different pathogens
Variable parts are engineered by shuffling and recombination of germline DNA when making antigen receptor DNA
What is negative selection in regard to the development of lymphocytes?
The process by which when a lymphocyte develops and expresses an antigen that is already expressed in the body, and so would cause autoimmunity, it is triggered to die
