Intro To Haematology Flashcards
(35 cards)
What is blood and what are the 2 components which make up blood?
Blood is a specialised connective tissue made up of plasma (liquid component 55%) and formed elements (RBC’s, WBC’s, platelets 45%).
What makes up the plasma?
Water, electrolytes, hormones, proteins, and waste products.
Name 2 proteins in plasma and give their function.
- albumin which maintains osmotic pressure.
- immunoglobulins play a role in immune defence.
Describe RBC’s.
AKA erythrocytes. Most abundant cell (99%) with a biconvave shape which increases surface area for gas exchange.
Describe WBC’s.
AKA leukocytes. Defends body against infections, highly dynamic. (1%). Bigger than RBC’s and have a nucleus. Can migrate out of capillaries into tissue fluid.
Name 5 subtypes of WBC’s.
Neutrophils, lymphocytes, and monocytes. They preform specific immune functions.
Platelets or thrombocytes. They are small disc shaped fragments from megakaryocytes in bone marrow which form blood clots in homeostasis.
What is haemotopoeiesis?
Formation of blood cells.
How does haemotopoiesis happen?
Occurs in the bone marrow where multipoietic haematopoietic stem cells differentiate into blood cells. The stem cells can self renew and differentiate into 2 different lineage.
Name and explain the 2 different lineages stem cells can differentiate into.
1) myeloid lineage produces erythrocytes (RBC’s) platelets and most types of WBC’s including neutrophils, eosinophils, basophils, and monocytes.
2) lymphoid lineage produces lymphocytes including B and T cells and natural killer cells.
What is erythropoietin?
A hormone released by kidney in response to low oxygen levels, ensures body can adapt to varying oxygen demands like during exercise.
What is haemostasis?
Clotting mechanism. Process which body prevents blood loss following vascular injury.
What are the 2 stages in haemostasis?
- primary haemostasis where platelets move to the site of injury and aggregate to form temporary plugs. Platelets adhere to exposed collagen at the injury site. They release chemical signals that recruit more platelets to amplify response.
- secondary haemostasis where coagulation cascade is activated resulting in the formation of stable fibrin clot. Clotting factors are proteins in the plasma which interact in the cascade to generate thrombins. Thrombins convert fibrinogen (soluble plasma protein) into fibrin strands (insoluble) that reinforces the platelet plug.
What determines blood group?
The presence or absent of specific antigen on the surface of RBC’s.
Describe the ABO system.
You can have type A, B, AB, or O blood, depending on antigen present.
Describe the Rh factor.
Refers to the presence (+) or absence (-) of the Rh antigen.
Name 5 types of blood disorders.
- anemia
- iron deficiency anemia
- leukaemias
- thrombocytopenia
- thrombocytosis
What is anemia?
Reduced number in RBC count/haemoglobin levels resulting in fatigue and shortness of breath.
What is iron deficiency anemia?
Insufficient dietary iron or chronic blood loss.
What is leukemias?
Cancers of blood and bone marrow due to the uncontrolled growth of WBC’s. This disrupts normal haematopoiesis, leading to symptoms like anemia, infections and bleeding.
What is thrombocytopenia?
Low platelet count which increases risk of bleeding.
What is thrombocytosis?
Excess of platelets leading to unwanted clot formation.
Name 2 types of WBC’s and give examples.
Granular leukocytes (neutrophils, eosinophils and basophils).
Agranular leukocytes (monocytes and lymphocytes).
What are platelets?
Cell fragments that pinch off from larger cells in the bone marrow. Flattened discs. They circulate for 9-12 days until removed by phagocytes. Function:
1) transporting chemicals which are important for clotting
2) forming temporary patch in walls of damaged blood vessels
3) contracting after a clot has formed
Explain insintric pathway.
- all clotting factors are in the blood
- clotting slower
- activated partial thromboplastin test (apTT)
