The Constituents of Blood and Eyrthropoiesis Flashcards
What is the liquid of blood called?
Plasma
What is serum?
This is the name given to plasma when clotting factors are removed.
Where is bone marrow found in adults?
Axial skeleton
What are the 2 subgroups that can be produced by multiple progenitor cells?
Myeloid
Lymphoid
Can precursor cells be easily identified?
No, they require immunophenotyping to identify them by the antigens they express.
Do RBCs have a nucleus?
No
Why are reticulocytes purple?
They are immature RBCs that have not yet lost their residual RNA.
What cell produces platelets?
Megakaryocyte
What are the 3 forms of granulocyte?
Eosinophil
Basophil
Neutrophil
What colour do eosinophils stain?
Red/Pink
What colour do basophils stain?
Blue
What is the most common WBC?
Neutrophils
How do neutrophils attack a pathogen?
Phagocytosis
Degranulation (which activates the complement system)
When are eosinophils typically elevated?
Allergic conditions
What is the role of a monocyte when it is in tissue?
Acts as a macrophage.
Carries out phagocytosis and acts as an APC.
When are lymphocytes elevated?
Viral infection
What is the single best test used to identify haematopoietic stem cells?
Immunophenotyping
Where is the most common site of bone marrow biopsy?
Posterior iliac crests.
What is the benefit to RBCs having a biconcave shape?
Allows for a high surface area:volume ratio.
Do RBCs have mitochondria?
No - as a result they can only carry out glycolysis.
How do RBCs produce energy?
Glycolysis only - there are no mitochondria to carry out the citric acid cycle.
Which form of iron is needed to bind haemoglobin?
Fe2+
What controls erythropoiesis?
Oxygen
What chemical is released from the juxtaglomerular cells of the kidney to increase RBC production?
Erythropoietin
Why is erythropoietin released?
To combat hypoxia.
What can cause a failure in erythropoietin production?
Kidney disease
Can be given exogenously to circumvent this.
Where is the main place for RBC breakdown?
The spleen.
How is heme broken down?
It is split into iron and porphyrin.
The porphyrin ring is then degraded to unconjugated bilirubin, which is then stored in the liver.
What can cause the oxidation of Fe2+ into Fe3+?
Free radicals (e.g. HPO)
These can damage RBCs.
What is Fe3+ within Hb called?
MetHb
What acts to defend against hydrogen peroxide (a free radical)?
Glutathione
This oxidises HPO to prevent its action.
What regenerates glutathione?
NADPH
This is limited by G6PD.
What inheritance is seen in G6PD disorders?
X-linked
This is more common in males.
How is most of the body’s CO2 carried to the lungs?
Bicarbonate
How many molecules of oxygen are held on each Hb molecule?
4
What globin chains are involved in adult Hb?
2 alpha
2 beta
What globin chains are involved in foetal Hb?
2 alpha
2 gamma
What role does generation of 2-3DPG have on O2 saturation?
It causes it to drop, producing a greater O2 release at tissues.
What is haemopoiesis?
The formation of blood cells.
What is the lifespan of a RBC?
120 days
What is the lifespan of a neutrophil?
7-8 hours
What is the lifespan of a platelet?
7-10 days
If haemopoiesis is stopped, which cell will be first to disappear?
Neutrophils - as these have the shortest lifespan.
What are myelocytes?
A precursor of both myeloblasts and neutrophils.
What cell is the only one capable of self-renewal?
Haematopoietic stem cells.
What is maturation?
Acquiring of function/proteins of a specific cell type.
At which week of development does the bone marrow take over as the predominant site of haematopoiesis?
Week 16
Which 2 systems allow blood to enter the bone marrow?
Periosteal arteries
Nutrient artery system
What happens to marrow cellularity with age?
It decreases.
Haematopoietic cells become replaced with fat.
What is the myeloid:erythroid ratio?
Refers to the proportion of granulocyte precursors to erythrocyte precursors.
Myeloid should be higher as these need replaced more rapidly.
What does a greater number of myeloid precursors than erythroid precursors indicate?
Normal patient.
What does a greater number of erythroid precursors than myeloid precursors indicate?
Haemolysis - a compensatory mechanism.
What stimulates neutrophil development?
G-CSF
What test is used to identify cells which are morphologically indistinguishable?
Immunophenotyping
