Haematology Flashcards
What is erythropoiesis
Production of red blood cells
What is erythropoietin
hormone that Controls erythropoiesis
How is the kidney involved in erythropoiesis
Releases erythropoietin in response to hypoxia which sends message to bone marrow to increase the number of stem cells committed to erythropoiesis
Why is an increase in erythropoietin bad
Increases the viscosity of the blood which is bad
What are reticulocytes
Immature red blood cells
What does an increase in reticulocyte counts in blood show
That there is an increase in erythropoiesis
What is the life span of a red blood cell
120
What is the measurement of the HB1AC
Blood test to monitor diabetes (measures the long term control over the last 3 or four months)
What is spherocytosis
Genetic condition in which the patient has an abnormal protein in their red cell membrane which means the red cell breaks down more rapidly
How to measure haemolytic anaemias and spherocytosis
- INcubate a sample of blood with radioactive chromium which binds to haemoglobin
- Measure the disappearance from blood and the sites of red blood cell destruction detected by surface counting
Where does the degradation of RBCs take place
In reticuloendothelial system (of spleen, liver, and bone marrow)
What is recycled when a red blood cell is broken down
Fe2+
What are causes of jaundice
Increase in rate of red cell degradation
Why does jaundice occur when there is an increased rate of degradation in red blood cells
Because porphyrin from haemoglobin is converted to bilirubin in the liver and the bilirubin gets deposited in the eyes and the eyes appear yellow
What are the globing chains linked by
non-covalent bonds
What subunits are there in haemoglobin
Two alpha and two beta
What subunits do fetal haemoglobin have
2 alpha and 2 gamma
How is Fe3+ oxidised to get to Fe2+
Oxidised by stomach acid
What is ferritin
Iron store
what happens to Fe2+ after coming out of the stomach
Turns into Fe3+ again
How does Fe3+ form ferritin
Binds to apoferitin to produce ferritin
How is iron taken to the bone marrow
Iron is released into blood to bind with transferrin (transport) and then that drivers iron to bone marrow to produce ferritin stores
In a blood test, what does ferritin count show
Iron stores
what substances increase the uptake of iron in the gastrointestinal tract
Erythroid regulator from bone marrow and an iron stores regulator
2,3-DPG mode of action
Present in RBCs and it reduces oxygen affinity of haemoglobin. In its absence haemoglobin would yield little O2 to tissues
How is fetal haemoglobin not having 2,3DPG useful
Have a higher O2 affinity
When is DPG higher
When arterial O2 reduced chronically ie with altitude or severe COPD
What is methaemoglobinaemia
-What is it caused by
Hereditary lack of glucose-6-phosphate dehydrogenase which is responsible for heaping haemoglobin in the reduced state. It may be caused by drugs
