1. Introduction: The scope of clinical haematology Flashcards
what is the blood components and products?
what is the transport function of blood?
In blood:
- Gases - Oxygen and carbon dioxide
In plasma:
- nutrients
- waste
- messages
Functions of blood:
Maintenance of Vascular Integrity - how does blood do this?
- Prevention of leaks by clotting factors and platelets
- Prevention of blockages by anticoagulants and fibrinolytics
another function of blood is protection from pathogens, how is this done?
- Phagocytosis and killing by granulocytes/monocytes
- Antigen recognition and antibody formation by lymphocytes
Pathogenesis of haematological abnormalities/what causes haeatological abnormalities?
•High levels
- Increased rate of production
- (Decreased rate of loss)
•Low levels
- Decreased rate of production
- Increased rate of loss
•Altered function (often genetically determined and often less important)
what is Haematopoiesis?
the formation of blood cellular components
Cells in blood all made form stem cells
Leukocytes are the white blood cells
Myeloid cells are all cells but lymphocytes
what are the features of stem cells?
- totipotent - can differentiate into all those cell types
- self-renewal (can divide and maintain their numbers)
- Binary fission and flux through differentiation pathways amplify numbers
- Flux regulated by hormones / growth factors - Some used therapeutically (erythropoietin, G-CSF, thrombopoietin agonists)
- Stem cell properties can now be ‘induced’
wher eis bone marrow and what does it look like?
- Where is it? - Bones: most in children, axial in elderly
- What does it look like? - Stroma and sinusoids
what is Erythroid differentiation an dwhat governs it?
- Erythroblast–>reticulocyte–>erythrocyte
- Erythropoietin - made in kidney in response to hypoxia
what is Reticulocyte count?
a measure of red cell production
what is polycythaemia?
Polycythaemia, also known as erythrocytosis, means having a high concentration of red blood cells in your blood. This makes the blood thicker and less able to travel through blood vessels and organs
what causes anaemia?
•Decreased production:
- Deficiency in ‘haematinics’ - iron, folate, vitamin B12
- Congenital: thalassaemias
•Increased loss:
- Bleeding, haemolysis
what are the consequences of anaemia?
Poor gas transfer: dyspnoea, fatigue
you cna classify anaemia in what way?
You can classify anaemia weather the cells are big or small
- Microcytes, macrocytes
- Polychromasia (a disorder where there is an abnormally high number of immature red blood cells found in the bloodstream as a result of being prematurely released from the bone marrow during blood formation)
- Burr cells in renal failure etc
what is the first line of defence if there is a broken blood vessel?
platelets
they clump together
what makes platelets?
Released by megakaryocytes in the bone marrow – platelets bud off from it