Red Cells and Haemolysis Flashcards

1
Q

what is haemopoesis?

A

ther production of blood cells

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2
Q

what are the sites of haematopoiesis from embryo to adulthood?

A

embryo- yolksac

birth- mostly bone marrow, liver

adult- bone marrow of axial skeleton

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3
Q

what is an erythrocyte?

A

mature red cell (doesn’nt have a nucleus)

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4
Q

what are mature red cells first called?

A

reticulocytes

(due to rRNA meshwork that can be seen under microscopy)

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5
Q

what cells are described as polymorph (segmented nucleus)?

A

neutrophils

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6
Q

what can cause an increase in neutrophils?

A

body stress- infection, trauma, infarction

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7
Q

what blasts are often elevated in people with allergies i.e. asthma/dermatitis?

A

eosinophils

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8
Q

how do eosinophils appear under microscope?

A

bi-lobed

bright red/orange granules

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9
Q

how do basophils stain under microscope?

A

large deep purple granules

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10
Q

what do basophil granules contain?

A

histamine

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11
Q

what is the production of red blood cells called?

A

erythropoesis

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12
Q

what regulates the poduction of red blood cells?

A

erythropoietin

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13
Q

where is erythropoietin released?

A

kidneys

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14
Q

what role do the kidneys play n eryhtropoeisis?

A

hypoxia sensed by kidney which then releases erythropoetin stimulating erythropoeisis

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15
Q

haemoglobin is what kind of protein?

A

tetrameric globular protein

  • 2 alpha
  • 2 beta
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16
Q

what is the haen group in haemoglobin?

A

porphyrin ring

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17
Q

where does red cell desrtuction usually take place?

A

in the spleen- red cells taken up by macrophages and contents recycled

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18
Q

what are the contents of red blood cells recycled to?

A

globin → amino acids

heam group → iron and bilirubin

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19
Q

what happens to the bilirubin formed from the breakdown of red cells?

A

binds to serum albumin and trasnferred to liver to become conjugated and is then excreted in urine and faeces

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20
Q

how is carbon dioxde transported in the blood?

A

10% dissolved in soln

30% bound directly to Hb

60% as bicarbonate

21
Q

what is the shape of the oxygen dissociation curve?

A

sigmoidal

22
Q

as one oxygen binds, on eunit changes its shape and the ability of oxygen to bind to the next unit. what is this called?

A

allosteric effect

23
Q

what happens to oxygen delivery if the curve is shifted to the right?

A

more oxygen delivered to the tissues

24
Q

what is the structure of fetal haemoglobin?

A

2 alpha chains and 2 gamma chains- HbF

25
Q

can feotal hameoglobin take oxygen from maternal curculation?

A

yes- diff shape means diff curve: if mums blood in placenta is 80% saturation foetal will be 90%

26
Q

why are red cells more susceptible ot damage?

A

biconcave shape

no mitochondria

no nucleus

27
Q

why is the lack of mitochondria and nucleus significant in red cells with regards to damage?

A

they have a limited metabolic reserve

can’t generate new proteins

28
Q

what is compensated hameolysis?

A

inc in red cell production to compensate for inc in red cell destruction

29
Q

what is decompensated haemolysis?

A

inc rate of red cell destruction exceeding bone marrow capacity for red cell production

Hb falls

30
Q

what is another name for decompnesated hameolysis?

A

haemolytic anaemia

31
Q

what is the bone marrow response to haemolysis?

A

reticulocytosis

erythroid hyperplasia

32
Q

which is more common extravascular or intravascular red cell desruction?

A

extravascular- at site of destruciton

33
Q

what happens in extravascular hameolysis?

A

release of protoporphyrin leading to escess unconjugated bilirubin

34
Q

what happens in intravascular haemolysis?

A

red cells destroyed in circulation spilling contents

35
Q

what are some causes of intravascular haemolysis?

A

ABO incompatible blood transfusion

G6PD deficiency

severe falciparum malaria (blackwater fever)

36
Q

ho wdo you investigate haemolysis?

A

FBC/film

reticulocyte count

serum unconjugated bilirubin

coombs test

37
Q

what is the purpose of coombs test?

A

tests for antibodies againt RBC

38
Q

what does membrane damage indicate on blood film?

A

spherocytes

39
Q

how is mechanical damage indicated on blood film?

A

red cell fragments

40
Q

how is oxidative damage indicated on blood film?

A

heinz bodies

41
Q

what immunoglobulin is seen in warm autoimmune haemolysis?

A

IgG

42
Q

what are causes of warm (igG) autoimmune haemolysis?

A

idiopathic

autoimmune disorders (SLE)

drugs (peniclllins)

infections

43
Q

what immunoglobulin is seen in cold autoimmune haemolysis?

A

IgM

44
Q

what are some causes of cold (IgM) autoimmune haemolysis?

A

idiopathic

infections (EBV, mycoplasma)

lymphoproliferative disorders

45
Q

other than autoimmune haemolyisis what other form of immune haemolysis is there?

A

Alloimmune haemolysis

46
Q

what can cause alloimmune haemolysis?

A

immune response

passive transfer of antibody- Haemolytic disease of newborn

47
Q

what are some mechanical causes of haemolysis?

A

Disseminated Intravascular Coagulation (DIC)

HUS (E.Coli 0157)

Leakign heart valve

infections i.e malaria

48
Q

what is the only type of haemolysis to show microspherocytes on blood film?

A

burns related haemolysis- red cells sheared as they pass through damaged capillaries