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.