Flashcards in ToB 20 Blood Cells and Haematopoiesis Deck (53)
What is the life span of a Red blood cell?
~ 120 days
What is the lifespan of a platelet?
~ 10 days
What is the lifespan of a neutrophil?
~ 2-4 days
What is the lifespan of a lymphocyte?
Between 1 day - years
Where are RBC's, platelets and most WBC's produced?
What organ removes blood cells from the circulation?
Name the 5 main (flat) bones which contain red bone marrow:
Red bone marrow has approximately what percentage of fat?
What is the name of the cell from which all blood cells are derived?
Multipotential haematopoetic stem cell
What are the 4 types of granular cells?
What is the difference between a monocyte and a macrophage?
Monocytes are the precursor of macrophages, and are present in the blood stream, while macrophages are present in the ECF
What are the 5 main functions of RBC's?
1- Carry oxygen to tissues
2- Maintain Hb in its reduced state
3- Carry Hb
4- Maintain osmotic equilibrium
5- Generate ATP
Why can't RBC's create protein?
No nucleus = no DNA = no mRNA = no protein
Why is it important that RBC's are biconcave?
1- Maximise SA:vol ratio, for quicker diffusion of O2 and CO2
2- Increase flexibility for passage through microcirculation
What is the diameter of a RBC?
What are the 2 configurations of a RBC?
Oxyhaemoglobin = R state (relaxed)
Deoxyhaemoglobin = T state (tight)
How would a decrease in pH affect the configuration of a RBC?
Promote T state = Deoxyhaemoglobin (Bohr shift)
How would a decrease in temperature affect the configuration of a RBC?
Promote R state = Oxyhaemoglobin
Describe the shape of the oxygen-dissociation curve:
What happens to the oxygen dissociation curve during the Bohr effect?
Curve shifts to the right
What is the Bohr effect?
When specific environmental changes: Decrease in pH, increase in CO2 and temp, affect the oxygen-binding affinity of RBC's, and promote the formation of deoxyhaemoglobin
Which globin genes predominate in an adult?
alpha and beta globins
Which globin genes predominate in a foetus?
alpha and gamma globins
When does the switch from gamma globin to beta globin occur?
~ 3-6 months after birth
Name the 2 main metabolic pathways in RBC's:
1- Embden Meyerhof pathway
2- Pentose Phosphate pathway
Which metabolic pathway allows RBC's to generate ATP?
Embden Meyerhof pathway
The Embden Meyerhof pathway metabolises Glucose to what?
Which metabolic pathway allows RBC's to generate NADPH?
Pentose Phosphate Pathway
The Pentose Phosphate Pathway metabolises Glucose 6-phosphate to what?
Fructose 6-phosphate and
What is the main function of the pentose phosphate pathway in RBC's?
to protect against oxidative damage (via Glutathione)
Cells in which organ detect a fall in pO2, resulting in Erythropoetin release?
Kidney (interstitial peritubular cells)
What is Erythropoetin?
Hormone produced and released from the Kidneys, which stimulates RBC maturation and release in bone marrow
Which hormone controls Erythropoesis, and where is it produced and released from?
Erythropoetin, from the Kidneys
Describe the negative feedback loop of Erythropoetin:
-Kidneys detect fall in pO2
-Kidneys increase production and release of Erthyropoetin
- Erythropoetin increases RBC maturation and release
- Kidneys detect rise in pO2
- Kidneys decrease production of Erthyropoetin
How is an old/damaged RBC broken down and excreted?
- Removed from circulation by spleen,
- Macrophage within Spleen breaks Haem into uncongugated bilirubin
- This converted to conjugated bilirubin in the liver
- Passes through bile duct into s. intestine
- Colonic bacteria deconjugate and convert to urobilinogen
- Absorbed and excreted by kidneys in urine
Tiny fractions of blood cells produced by Megakaryocytes
Which hormone controls platelet production?
In which organ are majority of platelets stored?
What is the main function of platelets?
Formation of blood clot
How do platelets promote blood clot formation?
- Adhesion to connective tissue
- Aggregate together = platelet plug
- Specific phospholipid membrane receptors to activate clotting cascade
What 2 bodies are found within platelets?
1- Dense bodies
2- alpha granules
What do the alpha granules of platelets contain?
What do the dense bodies of platelets contain?
Serotonin, ADP, Catecholamines and Calcium
Neutrophil maturation is controlled (mostly) by which growth factor?
Which growth factor enhances the chemotaxis and phagocytosis time of neutrophils?
Neutrophils contain granules. What is the function of these granules?
Contain enzymes (Defensins, Lyzozymes, Lactoferrin etc) for use when phagocytosing pathogens
Name the 4 main phagocytic cell types contained within the Reticuloendothelial system:
1- Monocytes (circulation)
2- Macrophages (tissue)
3- Kupffer cells (liver)
4- Microglial cells (CNS)
What are the main organs in the Reticuloendothelial system?
Spleen, Liver and Lymph Nodes
Lymph Nodes are mostly found in which 3 locations?
Which granular cell mainly mediate allergic reactions?
Where are T lymphocytes created?
Where do T lymphocytes mature?