lecture 24: resp . 6

Question 1

how is oxygen transported in blood

Answer 1

1. binds wit haemoglobin (specifically haem moiety)
2. small amount dissolves in solution

Question 2

how does haemoglobin work

Answer 2

heamoglobin molecule has 4 haem moieties (a structure containing a iron ion) that can each transport one oxygen. as an oxygen atom binds to one moiety, the molecule twists shape and another moiety is exposed and so on

Question 3

oxygen dissociation curve for haemoglobin

Answer 3

• when partial pressure of oxygen in tissues is high, % staturation of haemoglobi is high
• when partial pressur eof oxygen in tissues is low, % saturation is also low
• sigmoidal curve
• change in Hb affinity depending on O2 partial pressure

Question 4

physiological significance of oxygen dissociation curve for haemoglobin

Answer 4

when in lungs, affinity is high because partial pressure is high so favours loading, in tissues partial pressure is low, so affinity is low and favours downloading

Question 5

why does haemoglobin oxygen affinity for oxygen change

Answer 5

in tissues, carbonic acid is produced and the acidic environment means less affinity for O2, in lunsg tere is less Co2 so a higher pH since less carbonic acid produced. O2 is taken up

Question 6

saturation of oxygen in blood

Answer 6

haemoglobin molecules that are fully bound with oxygen

Question 7

content of oxygen in blood

Answer 7

oxygen content refers tot he concentration of oxygen in the blood measures in mL of oxygen per 100 mL or L of blood

Question 8

bohr shift

Answer 8

higher affinity in lungs from decreased CO2, H+, temperature, DPG

Question 9

chloride shift

Answer 9

at the tissues, as erythrocyte produces and loses bicarbonate when CO2 and water are reacting, electroneutrality is upset so chlroide moves into the cell. this is reversed at the alveolus

Question 10

why do foetal haemoglobin and myoglobin have left shifted dissociation curves?

Answer 10

foetal haemoglobin has a higher affinity in order to facilitate movement of oxygen from placenta to the foetus

Question 11

CO2 transport in bood

Answer 11

1. dissolves in solution
2. chemical in form of HCO3^-
3. combines with amine groups
4. as H2CO3 and CO3^- ions

Question 12

how do blood gas levels control the rate and depth of breathing?

Answer 12

chemoreceptors (peripheral near major blood vessels, central in medulla oblongata) detect blood gases