Lecture 4 Flashcards
How is the Shape of rbcs related to function ?
Do rbcs have nucleus, rna or mitochondria?
how do RBCs make ATP?
Small and flexible - can move through capillaries
- carries oxygen and C02 (flat large surface area)
- no nucleus or rna or mitochondria
- glycolytic pathway - to produce ATP (if have defects in enzyme pathways can get haemolysis)
What is Thalassemia
- body makes abnormal form of haemoglobin
- defective globulin chains
- cannot carry as much oxygen
- fatigue, weakness, slow growth, paleness
Names of rbc as it goes through erythropoiesis
How many cells are made from 1 pro-normoblast?
Changes in the cell as it forms a mature rbc?
pronormoblast, basophilic normoblast, polychormatic normoblast, pyknotic normoblast, reticulocyte, mature red cell
1 pronormoblast makes 16 red blood cells (7-10 days)
-driven by erythropoetin
changes- increase in amount of haemoglobin (become more red) , chromatin clumping, and loss of rna, nucleus is lost
What does Erythropoietin do?
where is it made?
what is the feedback loop for this?
made in kidney, responds to low oxygen - feedback loop with kidney
-stimulates rbc development
Feedback
- kidney senses low oxygen, stimulates erythropoetin to be made, and this goes and drives colony forming units
- and then the reticulocyte goes into the blood and depedning on oxygen delivery to kidney (from rbcs) will either increase or decrease feedback loop
What are 5 things that impact oxygen delivery to the kidney
LEARN -could be a good question!? - she said.
- no. of red cells
- amount of oxygen in atmosphere
- oxygen dissociation curve
- some haemoglobins inherited forms - dont dissociate their oxygen redily - high affinity haemoglobins- get erythropotein switched on because the haemoglobin is nt giving the oxygen to the kidney
- poor renal circulation - not getting many rbc through
- low cardiac function
effects of erythropoietin
- what receptors does it act through?
- what does it do?
acts through specific epo receptor to increase rbc production (in the bone marrow)
- stimulation throuh BFU-E and CFU-E
- increased haemoglobin synthesis
- reduced rbc maturation time
- increased reticulocyte release
Overall results in increased haemoglobin and therefore increased oxygen delivery
When to use erythropoetin
- when patients have renal failure
- when there is anemia of renal failure as not enough erythropotein is being produced to make enough rbcs
- potential for abuse - eg. athletes
definitions for
Haematocrit
Haemoglobin
what can affect haemoglobin conc?
Haematocrit - fraction of red blood cells in a volume of blood (is a ratio) (same as packed cell volume)
haemoglobin - measurement taken as concentration of haemoglobin molecules (grams/liter)
haemoglobin conc can be effected by total plasma volume - e.g if a person is dehydrated the reduced plasma volume may mask anaemia or cause polycythemia
What does the Reticulocytes count reflect?
what happens when it is increased?
also what happens if there is anaemia and it is low?
normally no nucleated red cells in the blood
- however normal levels 1-2% of reticulocytes
- reticulocyte count rises when there is anemia after increased erythropotein levels,
- will be increased in blood loss ( haemorhage)
- if low reticulocyte count with anemia, then suggests something wrong with bone marrow
Things influencing normal reticulocyte response
- Marrow disease
- low iron, folate, b12 deficiencey
- lack erythropotein (renal disease)
- inefficient erythropoesis e.g thalasmemia
- chronic inflammation
Breakdown of red blood cells
- where
- where does iron and billirubin go?
-cells are removed in spleen
break down of rbcs, then have release of haemoglobin
-iron is reused , and bilirubin goes into the bile
