Transport of oxygen by haemoglobin 2 Flashcards
What happens to carbon dioxide at the gas - exchange surface?
Carbon dioxide is constantly being removed
How does the removal of carbon dioxide affect blood pH at the gas - exchange surface?
The pH becomes slightly raised due to the low concentration of carbon dioxide
What happens to carbon dioxide levels in respiring tissues?
Carbon dioxide is produced by respiring cells
How does a high pH affect haemoglobin?
It changes haemoglobin’s shape, enabling it to load oxygen readily
Why does hemoglobin retain oxygen while being transported in the blood?
The higher pH increases haemoglobin’s affinity for oxygen, preventing its release
How does carbon dioxide affect blood pH in respiring tissues?
Carbon dioxide dissolves in solution, lowering the pH of the blood
How does a lower pH affect haemoglobin in respiring tissues?
It changes haemoglobin’s shape, reducing its affinity for oxygen and causing oxygen to be released
How does this process ensure sufficient oxygen is delivered to tissues?
The more active a tissues, the more carbon dioxide it produces, leading to a greater release of oxygen from haemoglobin
What is the typical oxygen saturation of haemoglobin after passing through the lungs?
Around 97%, as not all haemoglobin molecules bind four oxygen molecules
Why does haemoglobin not always reach 100% saturation in the lungs?
In practice, not all haemoglobin molecules successfully load four oxygen molecules
What happens to haemoglobin saturation in tissues with a low respiratory rate?
Only one oxygen molecule is usually released per haemoglobin molecule, leaving it 75% saturated when returning to the lungs
How does oxygen unloading change in highly active tissues, such as exercising muscles?
Haemoglobin typically releases three oxygen molecules, leaving it with much lower saturation
What does haemoglobin saturation depend on?
The respiratory rate of the tissue - more active tissues cause more oxygen unloading
