Transport Of O2 And Co2 Flashcards
How many o2 binds to 1 RBC
1 RBC has 1 hemoglobin and 1 iron molecule and 1 iron molecule can hold 4 oxygen molecules (4O2) which in total makes 8 oxygen atoms!
Haemoglobin binds to Co2 to form carbaminohaemoglobin
Affinity of each gas with HB
Co (highest affinity)
Co2 (middle affinity)
O2 (least affinity)
Saturation
Despite the affinity of o2 being the least, we create an environment where HB is pressured to attach with o2 only.
High conc. Of o2 attached to HB = high saturation of HB with o2
Low conc. Of O2 attached to HB = low saturation of HB with O2
Lungs have a high conc. Of o2 therefore they have a high saturation
Respiring tissues have low o2 conc. Therefore they have a low saturation.
Attachment of O2 to HB
It is hard for the first o2 molecule to attach to HB. However, once it has binded to the HB, the HB changes shape and makes it easier for the remaining 3 molecules of o2 to attach.
This is why the saturation of O2 with HB is low at the beginning of the saturation graph.
Saturation of O2 in Lungs and Respiring tissues
Lungs can achieve 95.97% saturation of o2
Respiring tissues can achieve atleast 20.25% of saturation of o2
The Affect of Co2 inc on the partial pressure graph
If the pressure of co2 increases (e.g. in respiring tissues) they dissociate the curve and move it towards the right.
Dec. Of partial pressure of co2 makes the HB more efficient at taking up O2 and less efficient at releasing o2.
Dec. Of partial pressure of co2 makes the HB more efficient at taking up O2 and less efficient at releasing o2.
HOW O2 TRAVELS TO RESPIRING TISSUES
When HB binds with O2 to form HbO2, the HBO2 travels to the respiring tissues where the conc. Of Co2 is high.
Since the affinity for Co2 to bind with HB is more than O2, the Co2 kicks out the O (from HBO) and readily binds to the HB to form Co2HB. The O2 kicked out then diffuses down the conc. Gradient to the respiring tissues.
WAYS OF TRANSPIRATION FOR CO2
• 5% of Co2 is transported via plasma
• 85% of Co2 is transported in the form of hydrogen carbonate ions (HCo3)
• 10% of Co2 is transported in the form of Carbaminohaemoglobin.
Formation of carbonic acid and Bicarbonate
When Co2 reacts with H2O in the RBC to form carbonic acid with the help of the enzyme, carbonic anhydrase.
Then the carbonic acid (H2CO3) dissociates into H+ ions and HCo3 (hydrogen carbonate/Bicarbonate). The. The Hco3 leaves the RBC and moves into plasma.
Co2 + H2O —> H2co3 —-> H+ + HCo3
The Formation of Haemoglobinic acid
When H2Co3 was dissociated it formed H+ and HCo3.
The H+ had more affinity to bind to HB then O2. So when H is formed it kicks out the O2 from the oxyhemoglobin and binds to it to give Haemoglobinic acid (HHb).
The O2 that was kicked out then moves to the respiring tissues.
The Formation of Carbaminohaemoglobin
The rest of the Co2 binds to HB to form Carbaminohaemoglobin
HIGH ALTITUDES
At high altitudes the conc. Of O2 decreases and the so the partial pressure of O2 also Dec.
The saturation % of O2 in inhaled air Dec.
This can lead to altitude sickness, less aerobic respiration, high breathing and heart rate, inc in capillary diameter and nom of mitochondria.
What is Erythropoietin
Erythropoietin is a hormone released from the kidneys and partakes in the the formation of RBc’s.
After a few weeks at high altitudes the no. Of RBC inc. to compensate for the low availability of O2 in air
