The carriage of carbon dioxide
- Created by: Lois
- Created on: 14-12-12 09:56
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- Carriage of carbon dioxide
- How carbon dioxide is transported
- Carbon dioxide ia released from respiring tissues.
- It must be removed from these tissues and transported to the lungs.
- Carbon dioxide in the blood is transported in 3 ways:
- 5% is dissolves directly in the plasma
- 10% is combined directly with haemoglobin to form the compound carbamino-haemoglobin
- 85% is transported in the form hydrogen-carbonate ions (HCO3-)
- 10% is combined directly with haemoglobin to form the compound carbamino-haemoglobin
- 5% is dissolves directly in the plasma
- Carbon dioxide ia released from respiring tissues.
- How hydrogen-carbonate ions are formed
- 1) As CO2 diffuses into the blood, some of it enters the red blood cells.
- It combines with water to form the weak acid carbonic acid.
- This is catalysed by the enzyme carbonic anhydrase: CO2+H2O=H2CO3
- It combines with water to form the weak acid carbonic acid.
- 1) As CO2 diffuses into the blood, some of it enters the red blood cells.
- Releasing oxygen
- As the blood enters respiring tissues, the haemoglobin is carrying oxygen in the form of oxyhaemoglobin.
- The oxygen tension of the respiring tissues is lower than that in the lungs
- this is because oxygen has been used in respiration.
- As a result the oxyhaemoglobin begins to dissociate and releases oxygen to te tissues.
- this is because oxygen has been used in respiration.
- The oxygen tension of the respiring tissues is lower than that in the lungs
- As the blood enters respiring tissues, the haemoglobin is carrying oxygen in the form of oxyhaemoglobin.
- Releasing more oxygen - the bohr effect
- The hydrogen ions released from the dissociation of carbonic acid compete for the space taken up by the oxygen on the haemoglobin molecule.
- So when the co2 is present, the H+ ions displace the oxygen on the haemoglobin.
- AS a result the oxyhaemoglobin releases more oxygen to the tissues.
- Where tissues (such as contracting muscles) are respiring more, there will be more co2.
- As a result there will be more hydrogen ions produced in the red blood cells.
- This make the oxyhaemoglobin release more oxygen. This is the bohr effect.
- At any particular oxygen tension, the oxyhaemoglobin releases more oxygen when more co2 is present.
- So when more co2 is present, haemoglobin is less saturated in oxygen.
- This makes the oxyhaemoglobin dissociation curve shift downwards and to the right (the bohr shift).
- The bohr effect result in oxygen being more readily released where more co2 is produced from respiration.
- This is just what the muscles need for aerobic respiration to continue.
- The bohr effect result in oxygen being more readily released where more co2 is produced from respiration.
- This makes the oxyhaemoglobin dissociation curve shift downwards and to the right (the bohr shift).
- So when more co2 is present, haemoglobin is less saturated in oxygen.
- At any particular oxygen tension, the oxyhaemoglobin releases more oxygen when more co2 is present.
- This make the oxyhaemoglobin release more oxygen. This is the bohr effect.
- As a result there will be more hydrogen ions produced in the red blood cells.
- Where tissues (such as contracting muscles) are respiring more, there will be more co2.
- AS a result the oxyhaemoglobin releases more oxygen to the tissues.
- So when the co2 is present, the H+ ions displace the oxygen on the haemoglobin.
- The hydrogen ions released from the dissociation of carbonic acid compete for the space taken up by the oxygen on the haemoglobin molecule.
- How carbon dioxide is transported
- 3) The hydrogen ions could cause the contents of the red blood cell to become very acidic.
- How hydrogen-carbonate ions are formed
- 1) As CO2 diffuses into the blood, some of it enters the red blood cells.
- It combines with water to form the weak acid carbonic acid.
- This is catalysed by the enzyme carbonic anhydrase: CO2+H2O=H2CO3
- It combines with water to form the weak acid carbonic acid.
- 1) As CO2 diffuses into the blood, some of it enters the red blood cells.
- To prevent this, the hydrogen ions are taken up by the haemoglobin to produce haemoglobinic acid.
- The haemoglobin is acting as a buffer (a compound that can maintain a constant pH).
- How hydrogen-carbonate ions are formed
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