Red blood cells: production and survival Flashcards
What does haematinic refer to? [4 marks]
Iron, vitmin B12, folate in red blood cell.
What are the first recognisable erythrocyte precursors on the bone marrow? [1 mark]
Proerythroblasts
Why is the cytoplasm of an erythrocyte basophilic? [1 mark]
Polyribosome
Why can hypoxia be caused by? [3 marks]
- Low erythrocyte count
- Decreased levels of haemoglobin
- Decreased availability of oxygen
What does erythropoietin do? [1 mark]
Stimulates red bone marrow to increase erythropoiesis
Which foods are sources of iron? [4 marks]
- Meat
- Eggs
- Vegetables
- Dairy food
How is iron absorbed? [2 marks]
- 5-10% absorbed in the duodenum and jejeunum
- Divalent metal transporter 1 and ferroportin transport iron from the duodenum and jejunum
What causes iron deficiency? [3 marks]
- Decreased uptake
- Increased demand
- Increased loss
How disease can cause malabsorption of iron? [1 mark]
Celiac disease (villi of the small intestine is damaged)
What is mean cell volume and how is that calculated? [2 marks]
- The average volume of each red blood cell
- The ratio of haematocrit to the red blood cells count.
What does low mean cell volume mean? [1 mark]
Microcytic anaemia
What is vitamin B12 and folic acid needed for? [3 marks]
- RBC maturation
- DNA synthesis
- Formation of thymidine triphosphate
What is vitamin B12 a coenzyme for? [1 mark]
Methionine synthase
What is intrinsic factor and where is it produced? [2 marks]
- A glycoprotein produced in the stomach
- Binds to Vitamin B12 and takes it to the ileum
What is the cause if folate deficiency? [4 marks]
- Inadequate intake
- Absroption defect (i.e. coeliac, Crohn’s, Tropical sprue)
- Increased demands/losses
- Drugs
How do anticonvulsants cause folate deficiency? [1 mark]
They affect its absorption
What happens to erythrocytes in folate & B12 deficiency? [3 marks]
- Megaloblastic anaemia (large, nucleated immature progenitor)
- Macroovalocytes (large, oval RBC)
- Hypersegmented neutrophil
Which foods can you get vitamin B12 and folate? [4 marks]
VITAMIN B12: Animal produce
FOLATE: Liver, greens and yeast
What are the daily requirements and of vitamin B12 and folate? [2 marks]
VITAMIN B12: 1-2μg
FOLATE: 100-150μg
How much vitamin B12 and folate is stored in the body? [2 marks]
VITAMIN B12: 2-3μg
FOLATE: 100-150μg
Where is vitamin B12 and folate stored? [3 marks]
VITAMIN B12: Ileum
FOLATE: Duodenum & jejunum
How is vitamin B12 and folate transported in plasma? [2 marks]
VITAMIN B12: Bound to TCII and transported
FOLATE: It weakly binds to albumin
What else affects red blood cell production? [3 marks]
- Renal disease (affects erythropoiesis)
- Aplastic anaemia (failure of RBC production in bone marrow)
- Leukaemia
How is haemolytic anaemia classified? [3 marks]
- Hereditary/Congenital vs. Acquired
- Intrinsic vs. Extrinsic
- Intravascular vs. Extravascular
