gaseous exchange Flashcards
what are the 2 ways oxygen can be transported
Within the haemoglobin (Hb) in red blood cells - oxyhaemoglobin
Within blood plasma (approximately 3%)
what are the 3 ways carbon dioxide can be transported
Within the haemoglobin (red blood cells) to become carbamino-haemoglobin (HbCO).
Within blood plasma (approximately 7%).
In water (as carbonic acid).
what are the two kinds of respiration
-External Respiration occurs between the alveoli & blood capillaries (lungs)
-Internal Respiration occurs between the muscle cell membrane & blood capillaries (tissues)
describe the process of gas exchange
Blood arriving at the capillaries that surround alveoli in the lungs is deoxygenated, as the oxygen has been used by the tissues for respiration and carries waste + Co2
The air inspired into the alveoli is oxygen rich.
Gases either side of the alveoli membrane (wall) have different pressures, creating a pressure gradient (difference).
what is gas exchange
Gas exchange = the movement of gases across a membrane.
Gases always move or diffuse from areas of high PP to low PP.
what is particle pressure
the pressure (pp) a gas exerts within a mixture of gases
Where is the PP of O2 high/ low?
Alveoli – HIGH PPO2
Muscles – LOW PPO2
Where is the PP of CO2 high/ low?
Muscles – HIGH PP
Blood/capillaries – LOW PP
What does this mean in terms of movement of O2 or CO2?
O2
O2 diffuses from the alveoli (high) to the blood capillaries (low)
O2 then diffuses from the capillaries or blood (high) into the muscle (low).
CO2
CO2 diffuses from the muscle (high) into the capillaries (low).
CO2 then diffuses from the blood capillaries (high) into the alveoli (low)
what happens to the particle pressure in the alveoli during exercise
The partial pressure of 02 in the alveoli is the same (high) during rest and exercise – 105mmHg
what happens to the particle pressure in the muscles during exercise(co2)
PP of Co2 is higher in the muscles during exercise than at rest and venous blood, as Co2 is a bi-product of aerobic exercise.
what happens to the particle pressure in the muscles during exercise(o2)
PP of O2 is lower in the muscles during exercise than at rest as it has been used by the muscle tissues for aerobic respiration.
what happens to the concentration gradient during exercise
it gets bigger
if the concentration gradient is high how is the rate of diffusion
high
how many oxygen molecules can haemoglobin carry
4
where does association occur
Association (joining) of O2 to Hb to make oxyhemoglobin (HbO2) occurs at the alveoli
if the ppo2 decreases what happens to haemoglobin
the Hb more readily dissociates (drops off) oxygen, releasing it to the tissues (muscles)
what is Bohr shift
dissociation curves move right because the muscles so it happens more readily
what are the 3 other effects of exercise which increase the dissociation of oxygen from Hb.
Increased body temperature
Increased Co2 (lowers pH levels of blood)
Increased production of lactic acid and carbonic acid (lowers pH)
