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46 Cards in this Set

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