Haemotology Flashcards
What is erythropoiesis?
The process of red blood cell (RBC) production.
Where does erythropoiesis occur?
In red blood bone marrow.
What is the process of erythropoiesis?
- Stem cell in bone marrow mature.
- Slowly fill with haemoglobin.
- Once bright red; reticulocytes are ready to escape.
- Get into capillaries and slowly mature.
What kind of mechanism is erythropoiesis
Homeostatis =
- involving receptor, controller and effectors.
What is plasma made of?
- 91% water.
- 7% plasma proteins.
What are the characteristics of plasma?
- Straw coloured.
- Sticky.
What are the most common plasma proteins?
Albumin.
Where is plasma albumin secreted?
Liver.
Which part of the plasma albumin helps control the osmotic pressure of blood?
The negative charge.
What is the functions of plasma albumin?
1) . Helps control blood pressure.
2) . Transport of substances =
- calcium carried by albumin.
3) . Antibodies (y-globulins).
4) . Increased viscosity.
5) . Blood buffers =
- solution resistant to changes in pH of blood (critical).
6) . Blood clotting.
What different types of plasma proteins are there?
- Albumins.
- Fibrinogen.
- Globulins.
- Transferrin.
What are the functions of blood?
1) . Transport =
- oxygen, nutrients, CO2, urea + hormones.
2) . Regulation =
- body temp, pH, circulatory fluid volume.
3) . Protection =
- preventing blood loss, preventing infection.
What is haemostasis?
Halts blood loss following damage to a blood vessel.
What are the 3 phases involved in haemostasis?
1) . Vascular spasm (constriction of the damaged vessel).
2) . Formation of a temporary platelet plug.
3) . Clotting of blood at the site of damage.
Describe the vascular spasm phase of haemostasis?
- Immediate protection.
- Contraction of muscle fibres in blood vessel walls.
- Causing vasoconstriction.
- Reduces blood flow.
Describe the platelet plug formation phase of haemostasis?
- Platelets attach themselves to the ‘sticky’ lining of blood vessels.
- Platelet plugs formed.
Describe the clotting phase of haemostasis?
1) . Substance released from damaged cells.
2) . Production of prothrombin activator.
3) . Activator converts prothrombin to thrombin.
4) . Thrombin converts fibrinogen to fibrin.
5) . Platelets and RBC’s form a clot that prevents blood loss.
What does a prothrombin activator do?
Converts prothrombin to thrombin.
What does thrombin convert fibrinogen to?
Fibrin.
What ion must be present for the conversions to occur (blood clotting)?
Calcium ions =
- Prothrombin –> thrombin.
- Fibrinogen –> fibrin.
What is fibrinolysis?
Process that leads to the breakdown of a fibrin clot (blood clot).
- normal process.
What is prothrombin?
A blood clotting protein (factor).
What vitamin is needed for the synthesis of prothrombin?
Vitamin K.
Where is vitamin K secreted?
In the liver.
What would a deficiency of vitamin k lead to in relation to blood clotting?
More bleeding (inhibits blood clotting).
What is the anti-platelet properties of aspirin?
Aspirin prevents formation of thromboxane (promotes blood clotting) by;
- binding to COX 1 enzymes –> which prevents platelet clumping.
Which health issue would aspirin be used for?
Stroke or heart attack =
- because it inhibits blood clotting (thromboxane), reducing risk.
Which enzyme generates thromboxane?
COX 1 =
- aspirin binds to it, inhibiting blood clotting.
What are anticoagulants?
Medicines that reduce the ability of the blood to clot
- used for cardiovascular diseases/strokes.
What are the 2 most common anticoagulants?
- Heparin.
- Warfarin.
What is the function of warfarin?
- Interferes the action of vitamin K.
- Results in inhibiting the production of prothrombin.
