Flashcards in Intro and Red Cells Deck (26):
What percentage of blood cells are RBCs?
What percentage of blood cells are white cells and platelets?
List the components of cell Plasma.
water, electrolytes, hormones, drugs, gases
-albumin (transport and colloidal osmotic pressure)
-globulins (transport and clotting)
State the main role of Neutrophils.
State the main role of Eosinophils.
Parasite killing and inflammation
State the main role of Basophils.
release of histamines
What are the different stages of Haemopoiesis?
1) Pluripotent Stem Cell
2) Mixed myeloid progenitor and Lymphoid Stem Cell
3) MMP becomes Committed Precursor cell, which can produce Megakaryocytes (develop to platelets), RBCs, Platelets, Mono- and Granulocytes
Which proteins influence WBC production?
-Colony Stimulating Factors (released during infection)
State the normal values for male and female Haematocrit.
What is the normal Haemoglobin value in males and females in g per 100lm of blood?
What is the Mean Corpuscular Volume?
Volume of individual RBCs. Calculated:
MCV=haematocrit/(RBC per litre)
Explain the significance of Rhesus positive and negative values in pregnancy.
If the mother is Rhesus -ve and the first child is Rh+ve, then mother produces antibodies against D antigen. Anti-D immunisation needs to be carried out on the mother in order to prevent Haemolytic disease of the second child.
How is erythropoiesis regulated via erythropoietin?
Hypoxia leads to the production of erythropoietin by the kidneys. EPO increases the number of erythropoietic stem cells.
Describe the processes in the maturation of reythropoietin stem cells.
Their nucleus is taken up by macrophages in the bone marrow. The resulting reticulocytes which have large amounts of ribosomal RNA synthetise large amounts of haemoglobin. They enter the blodstream and circulate for about 1 day before they mature to RBCs.
What happens to RBCs when they are degraded in the spleen, liver or bone marrow?
Their proteins are degraded and recycled, the iron is retained and the porphyrin from the Haem group is converted to bilirubin (only in the liver).
What is at the centre of a haemoglobin molecule?
Ferrous iron, Fe2+
What is the difference between adult and fetal haemoglobin?
Adult has alpha2beta2 arrangement, whereas fetal is alpha2gamma2
What are the stages in iron metabolism?
1) Fe3+ produced Fe2+ by mucosal cells in the duodenum
2) Ferritin is produced
3) mucosal cells release iron into blood to produce transferrin (transport)
4) Transferrin delivers iron to bone marrow where it is stored as Ferritin
5) Iron from these stores is used to produce Haemoglobin
6) 90% of iron is recycled in liver and spleen
Why does fetal Haemoglobin have a higher affinity for oxygen than adult Hb?
Because it has gamma subunits, which make binding of DPG molecules impossible. DPG is a molecule that reduces oxygen affinity.
What happens to the level of diphosphoglycerate when arterial oxygen levels are low?
It increases in order to release more oxygen to tissues.
What is the consequence of Carboxyhaemoglobin in the blood?
It does not readily dissociate, therefore reduces the number of oxygen carrying RBCs.
What is methaemoglobinaemia?
When iron is in the ferric (Fe3+), not ferrous state.
This means that Hb cannot carry oxygen.
What can cause methaemoglobinaemia?
1) hereditary lack of G6P dehydrogenase
2) some drugs, eg. antimalarials and sulphonamides
How is carbon dioxide carried in the blood?
10% is dissolved. 30% is bound to Hb. 60% is transported as HCO3-.
What is the Chloride shift?
The exchange of bicarbonate against chloride across the cell membrane of RBCs.