Fetal haemoglobin and carbon dioxide

?
  • Created by: Emily.T
  • Created on: 15-01-18 21:20
Does fetal haemoglobin haver a HIGHER or LOWER affinity for oxygen than adult haemoglobin?
Higher
1 of 20
Why does fetal haemoglobin have a higher affinity for oxygen than adult hameoglobin?
Because it is better at absorbing oxygen than its mother's blood at the same partial pressure of oxygen
2 of 20
How does the fetus get its oxygen from its mother?
Via the placenta - the fetus is completely dependent on its mother to supply it with oxygen.The mother's oxygenated blood runs close to the deoxygenated fetal blood, so oxygen is removed from maternal blood as they move past each other
3 of 20
Why does a fetus have to have a higher affinity for oxygen than its mother?
If the fetus had the same affinity as its mother, then little or no oxygen would be transferred to the blood of the fetus
4 of 20
How does the partial pressure of carbon dioxde (pCO2) affect oxygen unloading?
The higher the partial pressure of carbon dioxide, the more easily haemoglobin gives up oxygen
5 of 20
How does the partial pressure of carbon dioxide increase in cells?
Respiring cells release carbon dioxide which increase the pCO2
6 of 20
How does the pCO2 affect the rate of oxygen unloading?
It increases it
7 of 20
What is the name given to the effect of CO2 concentration on the uptake and release of oxygen by Hb?
The Bohr effect
8 of 20
What are the results of the Bohr effect?
1) In active tissues with a high pCO2, Hb gives up its O2 more easily 2) In the lungs where the proportion of CO2 in the air is low, O2 binds to Hb more easily
9 of 20
How is carbon dioxide transported around the body?
In the blood
10 of 20
What are the 3 ways that CO2 is transported from the tissues to the lungs?
1) About 5% is carried dissolved in the plasma 2) 10-20% is combined with the amino groups in the polypeptide chains of Hb to form carbaminohaemoglobin 3) 75-85% converted into hydrogen carbonate ions (HCO3-) in cytoplasm of RBCs
11 of 20
What form is most of the CO2 that diffuses into the blood from cells transported as?
Hydrogen carbonate ions (HCO3-)
12 of 20
How is CO2 transported in the blood? (Steps 1-3)
1) CO2 diffuses from body cells into RBC 2) Enzymes in RBC (carbonic anhydrase) combines CO2 + H2O to form carbonic acid 3) Carbonic acid dissociates into hydrogen and HCO3- ions, the HCO3- ions diffuse out of RBC
13 of 20
How is CO2 transported in the blood? (Steps 4-6)
4) Chloride ions enter the RBC (chloride shift) to maintain the charge 5) Too much hydrogen ions (H+) cause oxyhaemoglobin (HbO8) to split into Hb and 4O2 - which diffuses into blood plasma 6) The Hb and H+ combine to form haemoglobinic acid
14 of 20
What is the chloride shift?
The movement of chloride ions (Cl-) into RBCs as hydrogen carbonate ions diffuse out down a conc grad to maintain the electrochemical equilibrium
15 of 20
What does the chloride shift do?
Prevent any change in pH that could affect the cells
16 of 20
What does the removal of CO2 and converting it into HCO3- ions do?
Helps erythrocytes maintain a steep conc grad for CO2 to diffuse from the respiring cells into the erythrocytes
17 of 20
What happens to the carbonic acid at the lungs?
It is broken down (in a reversible reaction) back into CO2 & H2O via carbonic anhydrase, releasing free CO2 which diffuses out of the blood into the lungs to then diffuse into the alveoli to be breathed out
18 of 20
What happens to the chloride ions at the lungs?
They diffuse out of the RBCs back into the plasma down an electrochemical gradient
19 of 20
What role does haemoglobin play in the process of catalysing carbonic acid?
Acts as a buffer and prevents changes in the pH by accepting free H+ ions in a reversible reaction to form haemoglobinic acid
20 of 20

Other cards in this set

Card 2

Front

Why does fetal haemoglobin have a higher affinity for oxygen than adult hameoglobin?

Back

Because it is better at absorbing oxygen than its mother's blood at the same partial pressure of oxygen

Card 3

Front

How does the fetus get its oxygen from its mother?

Back

Preview of the front of card 3

Card 4

Front

Why does a fetus have to have a higher affinity for oxygen than its mother?

Back

Preview of the front of card 4

Card 5

Front

How does the partial pressure of carbon dioxde (pCO2) affect oxygen unloading?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes resources »