Lecture 1: Red Blood Cells Flashcards

1
Q

how soluble is oxygen in plasma

A

poorly soluble

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2
Q

how many ATP molecules does a glucose molecule produce

A

36

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3
Q

what is haemoglobin made of

A

4 subunits, each with a small haem group and large globin peptide

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4
Q

properties of haem group

A
  • porphyrin ring
  • rigid, 2D and highly coloured due to sharing of electrons
  • ferrous, so conjugated to Fe2+
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5
Q

which subunits are present in adult haemoglobin

A

2 alpha and 2 beta

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6
Q

which subunits are present in foetal haemoglobin

A

2 alpha and 2 gamma

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7
Q

what is the Bohr effect

A
  • increased blood CO2 level decreases affinity

- decreased blood pH level decreases affinity

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8
Q

which forms are CO2 transported in

A
  • dissolved
  • carbamino
  • HCO3-
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9
Q

how is CO2 transported as HCO3-

A
  • CO2 and H+ converted to H2CO3 by carbonic anhydrase

- H+ binds to Hb and HCO3- leaves through Band 3, a chloride carbonate exchanger

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10
Q

what causes rightward shifts of the haemoglobin dissociation curve

A
  • CO2
  • H+
  • Cl-
  • 2,3-DPG (diphosphoglycerate)
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11
Q

what does 2,3-DPG do

A

binds to haemoglobin to lower affinity for oxygen

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12
Q

what is foetal hameoglobin’s affinity to 2,3-DPG like

A

lower than adult, so higher affinity for oxygen

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13
Q

what happens in active muscles

A
  • O2 leaves Hb
  • CO2 and H+ bind to Hb
  • HCO3- leaves RBC to plasma
  • Cl- leaves plasma to RBC
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14
Q

what is breathing controlled by

A

CO2, O2 and H+

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15
Q

what is the main driver to increase respiratory rate

A

H+ in cerebrospinal fluid, as CO2 gas enters CSF and acted on by carbonic anhydrase to make H+ and carbonic acid

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16
Q

what is the size of a red blood cell

A

7 micron diameter

2 micron height

17
Q

where does erythropoiesis happen after birth

A

membraneous bone marrow, eg vertebrae

18
Q

where does erythropoiesis happen before birth

A
  • liver
  • spleen
  • lymph nodes
  • yolk sac
19
Q

development stages of stem cell differentiation

A

1) multipotent stem cells
2) multipotent progenitor cells
3) lineage-committed progenitor cells
4) mature cells

20
Q

what is required for a haematopoietic stem cell to become an erythroblast

A

erythropoietin

21
Q

what is required for an erythroblast to become erythrocytes

22
Q

what is erythropoietin

A
  • a cytokine made in the kidney during hypoxia
  • stimulates erythropoiesis
  • performance enhancing drug for athletes
23
Q

what is a reticulocyte

A
  • red blood cell precursor, still contains nucleus and organelles
  • lasts for 2 days in the blood
24
Q

how can reticulocyte count be used

A
  • diagnostic tool in anaemia
  • indicator of bone marrow activity
  • high levels in haemolytic anaemias
  • low levels when erythropoiesis is low
25
what is methaemoglobinaemia
- Hb cannot transport O2 - ferric haemoglobin Fe3+ rather than ferrous Fe2+ - due to congenital globin mutations, hereditery decrease of NADH, toxic substances
26
treatment for CO poisoning
95% O2 and 5% CO2
27
what are polycythaemias
- increase in number of RBCs | - increased viscosity of blood
28
what is pathological polycythaemia
- polycythaemia vera - is a neoplasm - no cure, treat with venesection - all ages, increases with age - might be genetic
29
how is Fe stored intracellularly
- stored as ferritin and haemosiderin | - in reticulo endothelial system
30
why is vitamin B12 and folic acid important
- essential for forming DNA - deficiency causes megaloblastic anaemia, fragile cells - deficiency caused by diet, malabsorption or increased utilisation - deficiency treated with oral folic acid and intramuscular hydroxocobalamin (B12)
31
what sort of anaemia is caused by iron deficiency
- hypochromic microcytic anaemia | - cells keep dividing but can't fill up with Hb
32
what sort of anaemia is caused by folic acid or B12 deficiency
- megaloblastic anaemia | - cells keep filling up with Hb but can't divide fast enough