Flashcards in Haematology Deck (70)
How much blood does an average adult have?
- Females = 4-5 L.
- Males = 5-6 L.
- 8% of adult weight.
Loss of how much blood is life threatening? And what may be some causes of blood loss?
- Loss of 1L is life threatening.
- rapid/chronic loss.
- decreased production.
- increased destruction.
What is blood composed of?
- 55% plasma.
- 45% blood cells (these are split into white blood cells, platelets and red blood cells).
What is the blood plasma composed of?
- Plasma is the liquid portion of blood. It helps maintain pH at 7.3-7.4.
- Comprised of water 92%, protein 7% and other solutes (such as waste products/respiration gases) 1%.
What are the white cells and platelets in blood?
- Platelets: fragments of cells involved in clotting.
- White cells: leukocytes (made up of neutrophils, basophils, monocytes, lymphocytes and eosinophils).
What are the red cells in blood?
- There is 1 white cell for every 1-2 thousand red cells so lots.
- They make up the biggest proportion of blood after plasma.
What are the functions of blood?
- transport: nutrients such as CO2, O2 and waste.
- regulates: water, temp, pH.
- communication: hormones.
- protects: antibodies, defensive cells/clots.
What is haematopoiesis?
- Formation of blood.
Where are the mature and immature elements of blood found?
- Mature: circulate.
- Immature: remain in bone marrow.
How many new blood cells are produced daily?
10(11) - 10(12).
Where do blood cells originate from?
- Haeomatopoetic stem cells (these cells are self renewing).
What do we say about cells at the top of the differentiation tree? (I.e. The photo which starts with haeomatopoetic stem cell at top).
- Immature but huge potential for division.
What do we say about cells at the bottom of the differentiation tree? (I.e. The photo which starts with haeomatopoetic stem cell at top).
- Mature but can't divide.
Where is the site of haematopoesis?
- first few months gestation: yolk sac.
- liver and spleen take over until 7 months.
- at 7 months bone marrow key in blood cell formation.
- during childhood and adulthood bone marrow only source of new blood cells in healthy individuals.
Where does medullary haematopoesis take place?
- In bone marrow.
Where does extramedullary haematopoesis take place?
- Outside bone marrow in liver and spleen.
- This only seems to happen when haeomatopoetic health is compromised.
- Memory and ability from when younger.
What are the three types of blood vessels?
What do arteries do?
- Tend to carry blood away from the heart.
- They have thick walls and narrow lumen.
- They work under high pressure and have a steady flow of blood.
What is the function of veins?
- They carry blood back to the heart.
- They have valves present to stop backflow.
- They therefore have a pulse flow.
What is the function of capillaries?
- Connect arteries to veins.
- They are one cell thick allowing material to pass through.
- Smallest of the blood vessels.
What is the largest filter of blood?
- The spleen: it has an important role in red cell integrity and also has immune roles.
What do the kidneys do?
- Filter blood, remove waste and extra water.
What does the liver do?
- Produces many proteins found in blood including clotting factors.
- It regulates levels of fats/amino acids/glucose and cleans blood of particles.
What does the lymphatic system do?
- Circulates lymph around tissues which carries nutrients and removes waste.
- This plays a vital role in immune system.
What is an erythrocyte?
- A mature red blood cell.
What is a reticulocyte?
- Immature blood cell.
How many reticulocytes are found in blood?
- 1% in adults.
- 3-6% neonates.
How can a reticulocyte count be carried out?
- They are identified by using a stain to identify ribosomal RNA.
Do RBCs have a nucleus?
- No, neither immature nor mature RBCs have one.
When will reticulocyte count increase?
- When erythropoiesis (production of RBCs) increases e.g. When someone heavily bleeding.
What do mature RBCs look like?
- These are known as erythrocytes.
- They are smaller than reticulocytes.
- They are found in circulating blood.
- Flexible bi-concave discs - no nucleus/organelles, uniform in size and shape.
- 8uM in diameter.
What do mature RBCs do?
- Transfer CO2 and O2.
What is lifespan of mature RBCs?
- 120 days in circulation.
- The spleen removes RBCs, about 1% broken down each day.
How much of a RBCs is filled with haemoglobin?
What is the normal range of mature RBCs in adults?
- Male: 4.5-6.5 x 10(12)/L.
- Female: 3.9-5.6 x 10(12)/L.
What is the main function of RBCs?
- To carry O2 to tissues and return CO2 from tissues to lungs.
What is haemoglobin?
- It's a tetrameric protein.
- Contains two alpha and two beta globin chains and each has its own haem molecule.
- Each haemoglobin molecule can carry up to four oxygen molecules.
Which hormone regulates erythropoiesis and where is it produced?
- Erythropoietin and its produced in kidney.
What is the stimulant to release erythropoietin in the tissues of the kidney?
- Low oxygen tension in these tissues.
What are platelets?
- Also known as thrombocytes.
- Megakaryocytes are platelet forming cells. They produce about 1000-5000 platelets each. Platelets contain granules.
- Life span can be a few days to a lifetime.
- They are 10-15x bigger than RBCs.
- They are the largest cells in bone marrow.
- They are involved in clotting. Once in blood they last about 7-10 days. - Normal range is 150-400x10(9)/L.
What are white blood cells?
- Also known as leukocytes.
- Nucleated large cells.
- Involved in defence and immunity. In health individual 4-11x10(9)/L.
- Composed of phagocytes (granulocytes such as neutrophils) and immunocytes (lymphocytes).
- Only mature cells found in blood, immature types are found in bone marrow and lymph nodes.
What is a neutrophil?
- 60-70% of leukocyte pop.
- Polymorphous nucleus (2-5 lobes).
- Phagocytose bacteria.
What is an eosinophil?
- 0.5-3% of leukocyte pop.
- Polymorphous nucleus (2 lobes).
- Bright red granules.
- Release toxins to defend against parasites.
What is a basophil?
- Rare in blood.
- 0.01-0.3% leukocyte pop.
- Polymorphous nucleus (2 lobes) -can't see once stained.
- Involved in inflammatory reactions.
- Produce heparin to prevent clotting.
- Important in parasite infections.
- Few h - few days life span.
What is a monocyte?
- 3-8% of leukocyte pop.
- Nucleus: kidney shaped.
- Can develop into macrophages or dendritic cells.
- Respond to inflammation signals.
- Life span 1-5 days.
What are the two primary organs where lymphocytes develop?
- Bone marrow and thymus.
Where do lymphocytes develop from?
- Haeomatopoetic stem cells which produce lymphoid stem cell.
Where are B cells and NK cells produced?
- In bone marrow.
What are the roles of B cells and NK cells?
- B cells: antibody mediated immunity.
- NK cells: immunological surveillance.
What is blood?
- Multifactorial tissue. Considered a form of fluid connective tissue (due to same embryonic origin as other connective tissues i.e. Mesodermal).
- Connects body systems together (CO2, nutrients, waste disposal).
Where are T cells produced?
What are lymphocytes?
- Make up 20-30% of leukocyte population.
- Round nucleus.
- Consist of b, t and NK cells.
- B: form antibodies.
- T: prepare foreign proteins for phagocytosis.
- NK: destroy infected cells and tumour cells.
- Life span few days - life time.
What can blood be used to detect?
- Used to detect haematology diseases.
- Haematological changes in other diseases.
- Monitor side effects of treatment e.g. Chemo, anti inflammatory and psychotic drug treatments.
If you have a high or low leukocyte count what can this mean?
- High: infection, inflammation, leukaemia.
- Low: medications, severe infection, autoimmune disease, BM failure.
What is average white cell count in normal indiv
Why would red cell count be increased or decreased?
- Increased: maybe because dehydration.
- Decreased: someone with anaemia.
What does full blood count include?
- RBC count.
- Hb count.
- Platelet count.
Normal ranges for Hb ?
- Male: 13.5-17.5g/dl.
- Female: 11.5-15.5g/dl.
- Decrease indicates anaemia.
What is normal platelet count
- Increase could be because myeloproliferative disorder affecting bone marrow, inflammation or infection.
- Decrease could be thrombocytopenia or leukaemia.
Which blood components can be transfused?
- RBCs - anaemic patients/bleeding patients.
- fresh frozen plasma - replace clotting factor.
- platelets - patients with low/dysfunctional platelets to prevent haemorrhage.
- white cells - rare. Usually given growth factor to stimulate production of own.
When blood transfused why is it usually leukodepleted?
- To protect the recipient as this will reduce the risk of some infections and transfusion reactions.
Where is ABO gene found?
- It's an autosomal gene found on chromosome 9.
- A + B are dominant over O and A + B are co-dominant.
Which antibodies do people with blood groups A, B, AB and O produce?
- A produce anti B antibodies.
- B produce anti A antibodies.
- AB produce neither anti A or anti B antibodies.
- O produce both anti A and anti B antibodies.
Which blood type is the universal recipient and which is the universal donor?
- Universal donor: O.
- Universal recipient: AB.
What is blood?
- it's a multifunctional tissue.
- it's considered a form of fluid connective tissue as has the same embryonic origin as other connective tissues (mesodermal).
- it connects the body systems together (O2, nutrients, waste disposal etc.).
What is erythropoiesis?
- process which produces red blood cells.
How do platelets stop bleeding?
- at site of injury there will be damage and bleeding.
- vasoconstriction occurs.
- platelet adhesion and aggregate and form a plug.
- this activates a clotting cascade.
- regeneration of fibrin strands form a mesh amount platelets.
What is bone marrow?
- it's a flexible tissue in the anterior of bones.
- in humans red blood cells are produced by cores of bone marrow in the heads of long bones in a process known as haematopoesis.
- bone marrow is also a key component of the lymphatic system, producing the lymphocytes that support the bodies immune system.
What is the thymus?
- primary lymphoid organ of the immune system.
- with the thymus t lymphocytes (t-cells) mature.
- located in front of the heart and behind the sternum.
- composed of two identical lobes.
- thymus provides an inductive environment for development of T cells from hematopoetic progenitor cells.
- largest and most active during neonatal and pre-adolescent periods.