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46 Cards in this Set
- Front
- Back
what is the most common form of anaemia?
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hypochromic microcytic
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when does microcytosis occur?
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when Hb sythesis is impaired
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what is the blood supply to the spleen?
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splenic artery
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what is the average splenic weight?
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135g
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what is the commonest cause of fever of recent onset?
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infection
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which cycle of development of malaria parasites occurs in the mosquito?
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sporogonic cycle
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which cycle of development of malaria parasites occurs in the vertebrate host?
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schizogonic cycle
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where do sporozoites go after entering the bloodstream?
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hepatocytes
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how many merozoites are contained in a mature schizont?
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up to 40 000
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what is the process of division of the thophozoites called?
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schizogony
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after the hepatocyte rupture and entry of the merozoites into the blood stream, which cells do the merozoites invade?
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red blood cells
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how long is erythrocytic schizogony for P. falciparum, vivax and ovale?
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48 hours
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which species of malaria has a period of development of an erythrocytic schizont of 72 hours?
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P. malariae
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what event initiates the development of fever in malaria?
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the release of merozoites and by products from red blood cells at the time of their rupture
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which species of malaria induces RBC adherence to the microvasculature of the brain and kidneys?
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P. falciparum
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t/f... sickle cell trait protects against severe or complicated P. falciparum malaria
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true
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where does Hb have high affinity for oxygen?
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lungs
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what are the changes in conformation of haemoglobin induced by?
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allosteric effectors
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what is the poylpeptide structure of foetal haemoglobin?
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alpha2gamma2
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what is the structure of adult heamoglobin?
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alpha2beta2
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t/f... oxyHb is in the T (tense) conformation
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false, oxyHb is in the R (relaxed) conformation
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why does exercising skeletal muscle have a lower pH?
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anaerobic glycolysis
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what is the effect of low pH on heamoglobin?
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the H+ binds to Hb and reduces its affinity for bound O2
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in what form is CO2 carried by Hb?
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carbamate
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what characteristic of the capillaries induces Hb to release bound O2?
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high CO2 concentration
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how does 2,3-BPG decrease the affinity of Hb for oxygen?
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by binding in the central cavity of deoxyHb
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which thalassaemias are caused by deletion of one of the two alpha globin genes?
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alpha+ thalassaemias
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how do malarial parasites in RBCs digest the host cell's Hb?
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within an acidic digestive vacuole
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how do quinolone antimalarial drugs work?
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inhibit the chemical polymerisation of haem which accumulates in the parasite and kills it
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which thalassaemia is associated with excess alpha chains?
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beta thalassaemia
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which chromosome contains the genes which encode for alpha globin chain production?
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chromosome 16
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how many genes encode of alpha globin chain production?
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2 on chromosome 16 (i.e. a total of 4)
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which chromosome contains the gene encoding for beta globin chain production?
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chromosome 11
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are most cases of beta thalassaemia due to point mutations or deletions?
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point mutations
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are most cases of alpha thalassaemia due to point mutations or deletions?
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deletions
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if three of the alpha chain production genes are abnormal, what is the resulting condition?
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Hb H disease
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what is the clinical effect of beta thalasseamia major?
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severe anaemia
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what is the globin chain composition of HbF?
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alpha2gamma2
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what is the globin chain composition of HbA?
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alpha2beta2
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what is the globin chain composition of HbA2?
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alpha2delta2
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t/f... people with beta thalassaemia will have increased HbA2 in the blood?
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true
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what are the blood film changes in beta thalassaemia?
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hypochromic microcytic anaemia, aniso/poikilocytosis, target cells, basophilic stippling, nucleated red cells, tear drop cells
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what is HbH disease?
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3 gene deletion; --/alpha-
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what is Hb barts hydrops fetalis?
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4 gene deletion; --/--
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what is alpha+ thalassaemia?
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1 gene deletion; alpha-
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do alpha thalassaemia carriers have raised HbA2?
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no
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