Gas transport

Question 1

Haemoglobin

Answer 1

2 alpha polypeptide chain
2 beta polypeptide chains
each chain form a protein subunit with a haem molecule

men generally have more the women

Question 2

oxygen transport in blood

Answer 2

oxyhaemoglobin (98.5%)
dissolved in plasma(1.5%)

movement between RBC and plasma is constant

Question 3

Haemoglobin

Answer 3

combines reversibly with oxygen
deoxyhaemoglobin (HHb + 02)
oxyharmoglobin (Hb02 + H)
amount of oxygen attached is saturation %

Question 4

Saturation

Answer 4

oxygen bound to Hb ÷ 0oxygen capacity of Hb x 100

Question 5

Carbon dioxide transport

Answer 5

20x more soluble than oxygen

carried in solution in plasma (5-10%)
chemically bound to amino acids (5-10%)
as bicarbonate (80-90%)

Question 6

CO2 transport

Answer 6

H20 + CO2 = H2CO3 = H+ + HCO3

water and carbon dioxide
carbonic acid
hydrogen ion and bicarbonate ion

requires the enzyme carbonic amhydrase

Question 7

At tissue

Answer 7

CO2 moves from the tissue into the plasma
most enters the RBC
some combines with HB
the rest combines with water to form hydrogen ion and bicarbonate
bicarbonate moves into plasma to act as a buffer
hydrogen combines with carbonic acid to release O2 and form HHb
O2 moves into tissue

Question 8

At the lungs

Answer 8

O2 moves from the alveoli into plasma
most moves into RBC forming oxyhaemoglobin and hydrogen is released from the haemoglobin
hydrogen combines with bicarbonate to form water and carbon dioxide
the carbon dioxide moves into the alveoli
carbon dioxide dissolved in the plame movess into the alveoli
haemoglobin releases carbon dioxide

Question 9

Acid balance

Answer 9

hydrogen ions are being continually produced through metabolism they are regulated by hydrogen ion excretion by the kidneys and carbon dioxide exercretio by the lungs

accumulation of carbon dioxide leads to an increase in hydrogen ions production and fall in blood pH causing respiratory acidosis

Question 10

Oxygen haemoglobin dissociation curve

Answer 10

saturation of oxygen against partial pressure of oxygen

high affinity- picks up oxygen easily offloads less easily
low affinity- offloads oxygen easily picks up less easily

Question 11

Release of oxygen

Answer 11

dissociation curve is steep between 20-40mmHg

small decrease in oxygen within the tissue results in a substantial unloading of oxygen from the blood

Question 12

Factor affecting dissaociation

Answer 12

temperature 
partial pressure of carbon dioxide
pH
Diphosphoglygerate
anaemia and carbon monoxide

Question 13

Bohr shift

Answer 13

moves to the right
dissociates earlier
deoxyhaemoglobin more readily accept hydrogen ions

high PCO2
low pH
high temperature

an increase in carbon dioxide, decrease in pH or increase in temperature causes a greater release of oxygen from haemoglobin`

Question 14

co2

Answer 14

when partial pressure of co2 increases this has the effect of a shirt to the right, seen in metabolically active tissues co2 is released causing Hb to have a lower affinity for oxygen therefore releases oxygen more easily into plasma of capillary and therefore more oxygen diffuses into respiring tissue.

Question 15

temperature

Answer 15

Temperature -when temperature increases this has the effect of a shirt to the right, seen in metabolically active tissues higher temperatures changes the shape of Hb molecule causing Hb to have a lower affinity for oxygen therefore releases oxygen more easily into plasma of capillary and therefore more oxygen diffuses into respiring tissue.

Question 16

pH

Answer 16

pH- when pH decreases this has the effect of a shirt to the right, seen in metabolically active tissues as they release CO2 which combines with water to form carbonic acid converted into bicarbonate releasing hydrogen ions. This causes Hb to have a lower affinity for oxygen therefore releases oxygen more easily into plasma of capillary and therefore more oxygen diffuses into respiring tissue.