Respiratory Physiology - Gas transport in the blood

Question 1

What 2 forms does oxygen travel in blood?

Answer 1

in solution in plasma and bond to haemoglobin in red blood cells

Question 2

Of 200ml, what is the split of Oxygen in plasma and RBC?

Answer 2

3ml PLASMA

297ml RBC

Question 3

What percent of CO2 is carried in RBC and plasma?

Answer 3

23% RBC

77% PLASMA

very soluble

Question 4

What is the O2 demand of resting tissue?

Answer 4

250ml/min

Question 5

How much blood can haemoglobin carry per litre of blood?

Answer 5

197ml

Question 6

How much O2 is there in each litre of blood?

Answer 6

200ml

197 haemoglobin
3ml plasma

Question 7

How much oxygen do we deliver to our peripheral tissues per minute?

Answer 7

1000ml per min

Question 8

What percent of oxygen in peripheries is metabolised?

Answer 8

25%

massive excess

Question 9

What is the common form of haemoglobin?

Answer 9

A

Question 10

What does each chain in haemoglobin associate with? and how many oxygens does each heam group associate with?

Answer 10

haem group

1 Fe2+

4 chains and associated with 4 molecules of O2

each 4 chains creates a binding site for 1 oxygen

carry 4 in total per RBC

Question 11

What is the reaction between the association of the iron atom and haem group called?

Answer 11

oxygenation reaction

weaker reaction than oxidation

Question 12

What is the cooperative biding of haemoglobin?

Answer 12

as the number of bound oxygen molecules increases in the association reaction, the apparent binding affinity increases

Question 13

What is the partial pressure of O2 in the alveoli and in arterial circulation?

Answer 13

100mmHg

Question 14

What does haemoglobin help maintain and how?

Answer 14

maintain partial pressure gradient of O2 in the alveoli and blood

by sucking the oxygen in until saturation

4 O2 per haemoglobin

Question 15

What does haemoglobin react with oxygen to form?

Answer 15

oxyhaemoglobin

HbO2

Question 16

How log does it take for the haemoglobin to be fully saturated with Oxygen?

Answer 16

0.25 seconds

Question 17

Does the fall in oxygen in plasma effect the oxygen bound to haemoglobin?

Answer 17

no, can fall by ~40% and has minimal effect in haemoglobin bound to oxygen

it is still 90% saturated

Question 18

When do plasma levels effect the oxygen bound to haemoglobin?

Answer 18

when they fall below 60%

Question 19

What s the normal partial pressure of mercury at resting tissues?

Answer 19

40mmHg

Question 20

Is veous blood deoxygenated?

Answer 20

no, still has 75% oxygenated, 25% has gone to tissues.

Question 21

What is venous and arterial partial pressure?

Answer 21

100mmHg is arterial

40mmHg is venous

Question 22

What happens to the partial pressure of someone who is anaemic?

Answer 22

nothing, PO2 is normal despite total blood O2 content being low

Question 23

Is it possible for red blood cells to be fully saturated in anaemia? and why?

Answer 23

YES

As saturation relies on partial pressure ad this is normal in anaemia

Question 24

What happens f you slide the resting cell arterial pressure to a higher partial pressure?

Answer 24

change the offloading of oxygen, not as strong gradient to offload

Question 25

What factors can cause the oxyhaemoglobin curve to shift?

Answer 25

pH PCO2 Temp DPG

Question 26

What does a decrease in pH, increase in PCO2 and temp... cause the oxyhaemoglobin curve to shift in what direction? (exercise)

Answer 26

right Bohr effect - promoting oxygen offloading at peripherals

Question 27

What does a decrease in pH, increase in PCO2 and temp... aid in loading or unloading of oxygen at peripherals?

Answer 27

unloading reduces affinity of oxygen and haemaglobin. the oxygen becomes less saturated with oxygen give oxygen to peripherals

Question 28

what happens to haemoglobins affinity for oxygen when... pH increases pCO2 decreases Temp decreases?

Answer 28

curve shift left increase affinity for oxygen

Question 29

What is occurring is pH increases pCO2 decreases Temp decreases?

Answer 29

hypothermia peripheral tissues cannot access oxygen as the affinity of haemoglobin has increased

Question 30

What is DPG?

Answer 30

diphosphoglycerate

Question 31

When do RBC produce more DPG?

Answer 31

HYPOXIA chronic lung or heart disease high altitudes help maintain oxygen release

Question 32

What is the Bohr effect?

Answer 32

describes red blood cells' ability to adapt to changes in the biochemical environment

Question 33

Does carbon monoxide have a higher affinity for haemoglobin than oxygen?

Answer 33

yes very high hard to get off once bound

Question 34

What diseases does CO occur?

Answer 34

hypoxia and anaemia

Question 35

What is the partial pressure gradient of CO2 from peripherals to arterial structures?

Answer 35

peripheral = 46 mmHg arterial = 40 mmHg