W10 RBC production + survival Flashcards

Question

Ability of RBC to survive depends on

Answer 1

Cytoplasmic enzymes involve in metabolic pathways because mature RBCs have no nucleus, mitochondria or ribosomes; therefore...unable to carry out oxidative phosphorylation and protein synthesis

Answer 2

life span 120 days 300 miles travelled through microcirculation 7.8 m diameter capillaries as small as 3.5 m

Answer 3

Autoimmune hemolytic anemia Caused by antibody production by the body against its own red cells: divided into cold and warm depending on whether the antibody reacts more strongly with red cell at 37oC or 4oC

Answer 4

Red cells are usually coated with IgG alone or with compliment, therefore taken up by the RE macrophages. Destruction occurs generally in the RE

Answer 5

Autoimmune Alloimmune Drug induced

Answer 6

Red Cell fragmentation Infection: Secondary

Answer 7

Hereditary Sickle cell diseases Thalassaemias

Answer 8

Hereditary G6PD deficiency PK deficiency

Answer 9

Hereditary spherocytosis | Hereditary elliptocytosis

Answer 10

Loss of membrane integrity, the RBCs become spherical Common hereditary haemolytic anaemia in N. Europ. deficiency in proteins with vertical interactions between the membrane skeleton and the lipid bilayer

Answer 11

Clinically milder | - mutations in horizontal protein, spectrin, leading to defective spectrin-Ankyrin association

Answer 12

Two main enzymes Glucose-6-Phosphate Dehydrogenase (G-6-PD) Pyruvate Kinase (PK) Support 2 main Metabolic Pathways Pentose Phosphate pathway Glycolytic pathway

Answer 13

Hb and rbc membranes are usually protected by reduced glutathione (GSH) from oxidant stress from the exposure to H2O2, certain medications, foods, or even infections. Heinz bodies are oxidised, denatured Hb

Answer 14

a role in protecting the red blood cell from oxidative damage NADPH in turn is required for the maintenance of reduced glutathione (GSH)

Answer 15

acts as an anti-oxidant G6PD catalyses the first step in the hexose monophosphate shunt which is necessary for producing NADPH a tripeptide that protects the RBC from oxidative damage

Answer 16

NADPH and GSH generation impaired Acute haemolysis on exposure to oxidant stress: oxidative drugs, fava beans (broad beans) or infections Hb precipitation – Heinz bodies G6PD deficiency most common known enzymopathy, estimated to affect 400 million people worldwide. …….but have evolutionary benefit

Answer 17

G6PD deficiency is X-linked, and seen in the same ethnic groups as haemoglobinopathies

Answer 18

have to avoid particular oxidative drugs, e.g. sulphonamides, dapsone, and notably quinone based anti-malarial drugs

Answer 19

leads to HA upon treatment with primaquine which stimulates H2O2 formation

Answer 20

patient have protection against severe malaria

Answer 21

Generates ATP to maintain red cell shape and deformability regulates intracellular cation conc. via cation pumps (Na/K pump), 3Na+ out 2K+ in

Answer 22

PK is an autosomal recessive disorder, with more than 100 mutations documented, resulting in low intracellular ATP generation affecting membrane structure.

Answer 23

causes a build up of glycolytic intermediates, including 2,3 biphosphoglycerate, which binds to and shifts the oxygen dissociation curve to the right 2,3 diphosphoglycerate

Answer 24

ATP is depleted: cells lose large amount of potassium & water, becoming dehydrated & rigid. because cation pumps fail to function. causes chronic non-spherocytic haemolytic anaemia excess haemolysis leads to jaundice, gallstones

Answer 25

film shows blistered cells (arrow), arrowheads show irregularly contracted cells

Answer 26

autosomal recessive, anaemia may worsen at times of infection or other stress; dense red cells with spicules (prickle cells) may be seen on the peripheral blood film

Answer 27

destabilisation of the overlying lipid bilayer and release of lipid in microvesicles

Answer 28

Abnormal synthesis of globin chain as in Sickle Cell Diseases. Reduced rate of synthesis of normal globin chains as in Thalassaemia.

Answer 29

clusters on chromosomes. 11 (ε, γ, δ and β) 16 (ζ and α 1+2)

Answer 30

HbA (α2β2), HbF (α2γ2), HbA2 (α2δ2)

Answer 31

Sickle Cell Anaemia (HbSS), homozygous, most common; heterozygote conditions: HbS/ßthal, HbSC, HbSD

Answer 32

point mutation leading to single amino acid change in beta-globin (sub of valine for glutamic acid; A to T) It’s the clinically most impt abnormality

Answer 33

HbS/βthal, MCV & MCH are lower than HbSS, clinical picture is of SCA, splenomegaly Hb C – lysine replaces GA at position 6 Hb D glutamine replaces GA Hb E lysine replaces GA at position 26

Answer 34

Loss of 1 beta-chain causes mild microcytic anaemia (thalassaemia trait) Loss of both (beta^0) causes thalassaemia major Excess α-chains precipitate in erythroblasts causing haemolysis and ineffective erythropoiesis

Answer 35

There can be loss of 1, 2, 3 or 4 alpha chanis

W10 RBC production + survival Flashcards

(59 cards)