haemoglobin and gas transport

Question 1

how much O2 can dissolve in plasma

Answer 1

3ml per litre

Question 2

how much of arterial O2 is extracted by peripheral tissues at rest

Answer 2

25%

so 75% reserve capacity

Question 3

what does haemolglobin do

Answer 3

increase oxygen carrying capacity of blood

sequesters O2 from plasma and so maintaints partial pressure gradient until becomes saturated

Question 4

what is the major determinant to which Hb is saturated

Answer 4

partial pressure of oxygen in arterial blood

Question 5

HbF and myoglobin

Answer 5

higher affinity for O2 than HbA

necessary for extracting from maternal/arterial blood

Question 6

where is myoglobin found

Answer 6

oxidative muscle fibres

Question 7

factors affecting Hb affinity for oxygen: pH

Answer 7

alkalosis (rise): increase

acidosis (fall): decrease

Question 8

factors affecting Hb affinity for oxygen: temp

Answer 8

rise: decrease
fall: increase

Question 9

factors affecting Hb affinity for oxygen:CO2

Answer 9

rise: decrease
fall: increase

Question 10

how is CO2 transported in blood

Answer 10

7% dissolved plasma
23% in RBC (with deoxyhaemoglobin to form carbamino compouds)
70% in RBC with water to form carbonic acid with forms bicarbonate and H+

Question 11

how does hypoventilation affect plasma PCO2

Answer 11

CO2 retention and so increased plasma H+

respiratory acidosis

Question 12

how does hyperventilation affect plasma PCO2

Answer 12

blowing off more CO2, leads to decreased plasma H+ and so respiratory alkalosis