Red Cell Structure and Function

Question 1

Can RBCs divide?

Answer 1

Nah - no nucleus

Question 2

Energy for RBC?

Answer 2

Glycolysis

-No mitochondria

Question 3

Red cells are full of?

Answer 3

Haemoglobin t carry oxygen (however therefore high oncotic pressure and high oxidation risk)

Question 4

What is adult haemoglobin?

Answer 4

HbA

Question 5

What does HbA consist of?

Answer 5

2 alpha and 2 beta globin chains

-Each globin chain has a haem group attached

Question 6

What does a haem group consist of?

Answer 6

Fe 2+ in a flat porphyrin ring

Question 7

One _______ molecule binds to 1______?

Answer 7

Oxygen

Ferrous iron

Question 8

What is fetal Hb?

Answer 8

Made up of 2 gamma chains and 2 alpha chains

Question 9

Immediate precursor to mature RBC erythrocyte?

Answer 9

Reticulocytes

Question 10

Function of reticulocytes?

Answer 10

Contain residual ribosomal RNA and are still able to synthesis Hb
Remain in bone marrow for about 1-2 days before being released into the ciruclation where they lose their RNA and become erythrocytes

Question 11

What regulated red cell production?

Answer 11

Erythropoietin (EPO)

Question 12

What produces erythropoeitin?

Answer 12

Kidneys

Question 13

What produces erythropoeitin?

Answer 13

Kidneys

Question 14

What stimulates production of EPO?

Answer 14

Hypoxia sensed by the kidneys

Question 15

EPO does what?

Answer 15

Stimulates bone marrow to produce more red cells

Question 16

Where does red cell destruction occur normally?

Answer 16

Spleen and liver

Question 17

Average red cell life span?

Answer 17

120 days

Question 18

Aged red cells way of dying?

Answer 18

Sensed and taken out by macrophages

Question 19

Globin chains in aged red cell?

Answer 19

Recycled to amino acids

Question 20

Haem group in aged red cell?

Answer 20

Broken down to iron and bilirubin

Question 21

What happens to bilirubin from broken down haem group?

Answer 21

Taken to liver and conjugated and then excreted into the bile (colours the faeces and the urine)

Question 22

Erythropoiesis diagram?

Answer 22

Question 23

What is the erythron?

Answer 23

RBCs are produced

Not a single organ a such just anywhere in marrow produced RBCs

Question 24

What is Embden-Meryof Pathway?

Answer 24

Kinda just fancy name for glycolysis

Question 25

Glycolysis produces?

Answer 25

2 ATP
2 NADH
2 Pyruvate

Question 26

Production of NADH in anaerobic pathway reverse Fe3+ to?

Answer 26

Fe2+

Question 27

Hexose monophosphate Shunt/pentose pathway?

Answer 27

Parallel pathway to glycolysis that produces NADPH which regenerates glutathione

Question 28

What do NAPDH and Glutathione do?

Answer 28

Protect RBC against oxidative stress

Question 29

What limits activity of Hexose monophosphate shunt/pentose pathway?

Answer 29

G6PD enzyme

Question 30

Faulty GP6D enzyme?

Answer 30

Due to X-linked disorder resulting in more oxidative stress on cells and premature red cell destruction

Question 31

CO2 transport?

Answer 31

10% dissolved in solution
30% bound directly to Hb
60% gets to lungs as bicarbonate

Question 32

Dissociation curve of oxygen?

Answer 32

Sigmoidal

Question 33

Binding of oxygen to one RBC unit?

Answer 33

Increases affinity of remaining subunits for oxygen, equally removal of oxygen decreases affinity

Question 34

Curve for foetal Hb Oxygen dissociation?

Answer 34

Shifted t left meaning higher affinity for oxygen allowing it to take oxygen from maternal circulation

Question 35

Myoglobin?

Answer 35

Monomeric in muscles

-Doesn’t show co-operativity and curve is hyperbolic

Question 36

What happens in rapapoport Lubering Shunt?

Answer 36

Generates 2,3-BPG which

• Shifts oxygen dissociation curve to right allowing more oxygen to be released
• UPREGULATED IN ANAEMIA

Question 37

Shifting the oxygen dissociation curve?

Answer 37

To the right: by increased H+, CO2 and temp, decreased pH

All of these would increase with respiration so makes sense that oxygen would be offloaded more readily