Intro to Haemotology Flashcards
What are the 3 blood components?
Plasma
Buffy coat
RBCs
What is found in plasma?
Clotting or coagulation factors
Albumin
Antibodies
What is found in the buffy coat?
Platelets
White cells or leucocytes
Functions of the blood
Transport (RBCs and plasma)
Maintenance of vascular integrity
Protection from pathogens
What is transported in red cells?
Gases - CO2 and O2 (haem binding to these)
How is vascular integrity maintained by the blood?
Prevention of leaks
- platelets and clotting factors
Prevention of blockages
- anticoagulants and fibrinolytics
How does the blood protect from pathogens?
Phagocytosis and killing
- granulocytes/monocytes
Antigen recognition and antibody formation
- lymphocytes
Abnormally high levels in the blood is due to either…
Increased rate of production
Decreased rate of loss
Abnormally low levels in the blood is due to either…
Decreased rate of production
Increased rate of loss
Where do all cells in the blood come from?
Uncommitted stem cells
Haematopoiesis definition
the commitment and differentiation processes that lead to the formation of all blood cells from haematopoietic stem cells
Another name for RBCs
Erythrocytes
Another name for WBCs
Leucocytes
What are myeloid cells?
Everything apart from lymphocytes
What type of stem cells form other types of cells outwith the blood?
Mesenchymal stem cells
Features of stem cells
Totipotent
Self renewal
Home to marrow niche (CXCR4)
properties can now be induced
How are stem cell numbers amplified?
Binary fission and flux through differentiation pathways
What is the flux of stem cells regulated by?
Hormones/growth factors
Where is bone marrow found?
Bone marrow
- mostly in children
- axial in elderly
Examples of RBCs pathologies
Polychromasia
Polycythaemia
Polychromasia definition
Abonormally high number of immature RBCs
Polycythaemia definition
Abnormally high number of haemoglobin in the blood
Differentiation stages of RBCs
Erythroblast - > reticulocyte - > erythrocyte
When is erythropoietin made and where?
Made in the liver in response to hypoxia
What does the reticulocyte count measure?
A measure of Red cell production
Consequences of anaemia
Poor gas transfer
Dyspnoea
fatigue
Causes of anaemia
Decreased production
- deficiency in haematinics (iron, folate, vitamin B12)
- congenital (thalassaemias)
Increased loss
- bleeding
- haemolysis
What make up the most common haematinics?
Iron
Folate
Vitamin B12
What are platelets produced by?
Marykaryocytes
Function of platelets
Haemostasis
Immune
What is the production of platelets regulated by?
Thrombopoietin
Regulation of platelet production
Thrombopoietin regulates it
Produced in liver
Regulation by platelet mass feedback (agonists - romiplostim can be used therapeutically)
Lifespan of platelets
7 days
Pathologies of platelets
Thrombocytosis Thrombocytopenia Altered function - aspirin - clopidogrel etc
Features of thrombocytosis
Reactive - goes away when underlying disease resolves
Thrombocytosis definition
Excessive number of platelets in the blood
Thrombocytopenia definition
Abnormally low level of platelets in the blood
Thrombocytopenia causes
Marrow failure
Immune destruction
Function of neutrophils
To ingest and destroy pathogens, especially bacteria and fungi
Function of neutrophils is controlled by what?
Interleukins
CSFs (colony stimulating factor)
Lifespan of neutrophils
1-2 days
speed of response of neutrophils
a few hours
Regulation of neutrophils is by….
Immune responses
- macrophages
- IL-17
Differentiation of neutrophils
Blast (acute myeloid leukaemia) Promyelocuye Myelocyte Metamyelocyte neutrophil