erythrocytes

Question 1

what gas is poorly soluble in plasma?

Answer 1

oxygen

Question 2

what is the equation for respiration in muscle?

Answer 2

C6H1206 + 6O2 —> 6CO2 + 6H2O + ~36 ATP

Question 3

what is the equation for anaerobic glycolysis?

Answer 3

C6H12O6 —> 2 lactate + 2 ATP

Question 4

what makes up 95% of the dry weight of red blood cells?

Answer 4

haemoglobin

Question 5

what is haemoglobin’s allosteric property?

Answer 5

cooperatively

Question 6

how many haem groups does each haemoglobin & myoglobin subunit have?

Answer 6

one

Question 7

what structure is a haem group?

Answer 7

a porphyrin ring

Question 8

why is the haem group coloured?

Answer 8

due to the sharing of electrons

Question 9

what state is the iron in a haem group?

Answer 9

ferrous (Fe2+)

Question 10

how many molecules of oxygen can one haemoglobin subunit carry?

Answer 10

one

Question 11

what subunits does adult haemoglobin (HbA) consist of?

Answer 11

2 alpha & 2 beta (tetramer as 4 subunits)

Question 12

what subunits does foetal haemoglobin (HbF) consist of?

Answer 12

2 alpha & 2 gamma

Question 13

what type of haemoglobin has a stronger affinity for oxygen?

Answer 13

foetal haemoglobin (HbF)

Question 14

what is the bohr effect?

Answer 14

the shift in oxygen dissociation curve caused by changes in the concentration of carbon dioxide or the pH of the surrounding environment

Question 15

what happens when there is a decrease in blood pH?

Answer 15

there is a decreased affinity of haemoglobin for oxygen

Question 16

what percentage of carbon dioxide is dissolved?

Answer 16

10%

Question 17

what percentage of carbon dioxide is a carbamino?

Answer 17

22%

Question 18

what percentage of carbon dioxide is HCO3-?

Answer 18

68%

Question 19

what shape is the myoglobin curve?

Answer 19

hyperbolic

Question 20

what shape is the haemoglobin curve?

Answer 20

sigmoidal

Question 21

what does the rightward shift (R) mean?

Answer 21

lowered affinity for oxygen

Question 22

what does muscle activity do to haemoglobin?

Answer 22

encourages it to release oxygen

Question 23

what is 2,3-DPG?

Answer 23

2,3-diphosphoglycerate (or 2,3-bisphosphoglycerate/2,3-BPG)

Question 24

what does 2,3-DPG do?

Answer 24

binds to haemoglobin and lowers it’s affinity for oxygen

Question 25

what does increasing the concentration of 2,3-DPG do?

Answer 25

decreases the affinity for oxygen causing a right shift in affinity

Question 26

why is blood slightly acidic?

Answer 26

due to carbon dioxide and lactic acid

Question 27

how does the oxygen leave the haemoglobin?

Answer 27

cooperatively

Question 28

what must happen before respiratory drive increases?

Answer 28

plasma oxygen must drop precipitously

Question 29

what is the main driver to increase respiratory rate?

Answer 29

H+ in cerebral spinal fluid (CSF)

Question 30

why is the response to carbon dioxide greater than the response to H+?

Answer 30

due to the blood h+ is only based on signal from carotid arch

Question 31

describe some features of a red blood cell

Answer 31

- biconcave - anucleate, lack organelles - 7 micrometre diameter & 2 micrometre height - contain haemoglobin - red when oxygenated - very flexible: fold and stack in blood vessels

Question 32

what are the functions of erythrocytes?

Answer 32

- 'bag' of haemoglobin | - transport oxygen and carbon dioxide

Question 33

how many days do erythrocytes survive for?

Answer 33

120 days

Question 34

what is erythropoiesis?

Answer 34

development/production of red blood cells

Question 35

where are red blood cells produced after birth?

Answer 35

bone marrow only

Question 36

where are red blood cells produced after age 20?

Answer 36

membranous bones only (eg - vertabrae)

Question 37

where are red blood cells produced during embryogenesis?

Answer 37

- liver - spleen - lymph nodes - yolk sac

Question 38

what is haematopoiesis?

Answer 38

development of all blood cells

Question 39

what are the 4 steps of development of erythrocytes from stem cells?

Answer 39

multipotent stem cells ---> multipotent progenitor cells | ---> lineage-committed progenitor cells ---> mature cells

Question 40

what is erythropoietin (EPO)?

Answer 40

- a cytokine/hormone that drives erythropoiesis | - performance-enhancing drug

Question 41

where is erythropoietin made?

Answer 41

made in the kidney in response to hypoxia in the kidney

Question 42

what is a reticulocyte?

Answer 42

a red blood cell precursor

Question 43

how many days does a reticulocyte last for and then what happens?

Answer 43

it lasts 2 days then it becomes a definitive red blood cell

Question 44

what can the reticulocyte count be used for, why and what are the results?

Answer 44

- used as a diagnostic tool in anaemia - it indicates the bone marrow activity - high in haemolytic anaemias & low when erythropoiesis is low

Question 45

what is methaemoglobinaemia?

Answer 45

- when haemoglobin cannot transport oxygen | - the iron in haemoglobin is oxidised to Fe3+

Question 46

what is methaemoglobinaemia due to?

Answer 46

- congenital globin mutations (HbM) - hereditary decrease of NADH - toxic substances

Question 47

what happens during carbon monoxide poisoning?

Answer 47

blood turns bright red

Question 48

what is affected first during carbon monoxide poisoning?

Answer 48

brain = disorientation

Question 49

what is the treatment for carbon monoxide poisoning?

Answer 49

95% oxygen/5% carbon dioxide

Question 50

what is polycythaemias?

Answer 50

- increased number of red blood cells | - increases viscosity of blood: clogs blood vessels

Question 51

what is physiologic polycythaemia due to?

Answer 51

living at high altitudes

Question 52

what percentage of all iron is in red blood cell haemoglobin?

Answer 52

65%

Question 53

how is iron stored?

Answer 53

intracellularly as ferritin and haemosiderin (30%)

Question 54

where is iron stored?

Answer 54

in the reticuloendothelial system | liver, spleen, erythrocytes, bone marrow, macrophages/monocytes

Question 55

how much iron is lost a day & what factors may alter this?

Answer 55

1mg/day and it is altered by pregnancy, menstruation and peptic ulcers

Question 56

what is vitamin B12 & folic acid needed for?

Answer 56

- important for rapidly dividing tissue | - essential for forming DNA (thymidine)

Question 57

what is the condition called where you are deficient in vitamin B12 & folic acid?

Answer 57

megaloblastic anaemia (macrocytic) | cells keep filling up but can't divide quick enough

Question 58

what is the treatment for megaloblastic anaemia?

Answer 58

oral folic acid, intramuscular hydroxocobalamin

Question 59

what condition is caused by iron deficiency?

Answer 59

hypochromic microcytic anaemia | cells keep dividing but cannot fill up with haemoglobin