Session 3 - Oxygen in the Blood Flashcards
How do you calculate [O2]dissolved?
Solubility x pO2
What are the two oxygen binding pigments and where are they found?
Haemoglobin - present in red blood cells
Myoglobin - present in muscle cells
Does haemoglobin have a high or low affinity for oxygen when in the T state?
Low affinity for oxygen in T state (tense)
Does haemoglobin have a high or low affinity for oxygen in the R state?
High affinity for oxygen in R state (relaxed)
What is the shape of the oxygen dissociation curve for haemoglobin?
Sigmoidal
Explain the Bohr shift.
- pH effects the affinity of haemoglobin for oxygen
- acidic conditions shift the dissociation curve to the right (promotes T-state of Hb)
- therefore in acidic conditions a high pO2 is needed to achieve the same amount of saturation
- alkaline conditions shift dissociation curve to the left (promotes R-state)
- therefore in alkaline conditions a lower pO2 is required to achieve the same amount of saturation
How is the Bohr shift significant in metabolically active tissues?
The pH is lower in metabolically active tissues, so extra O2 is given up to these tissues.
How does temperature affect oxygen dissociation?
Increased temperature also shift the dissociation curve to the right.
Metabolically active tissues have a slightly higher temperature.
So extra O2 is given up at these tissues.
What does 2,3-BPG stand for?
2,3-Bisphosphoglycerate
What is the effect of 2,-BPG?
It shifts the haemoglobin dissociation curve for O2 to the right. This allows more oxygen to be given up to the tissues.
When do 2,3-BPG levels increase?
With anaemia or at high altitude
What is the purpose of pulse oximetry?
Detects level of Hb saturation (detects difference in absorption of light between oxygenated and deoxygenated Hb)
Only detects pulsation arterial blood. Doesn’t say how much Hb is present.
