Transport Of Oxygen Flashcards
(14 cards)
What are erythrocytes?
Red blood cells
How are erythrocytes adapted for efficient transportation of oxygen?
No nucleus - more room to carry respiratory gases
Biconcave shape - maximises surface area for gas exchange
Small and flexible - can pass through narrow capillaries
Packed with haemoglobin - allows erythrocytes to carry respiratory gases - can carry 4 oxygen molecules
What do we call haemoglobin when it becomes oxygenated?
Oxyhaemoglobin
What do we mean by the conformation of haemoglobin?
Conformation (changes shape) of haemoglobin molecule changes
As O2 molecules become associated with it
What do we mean by dissociation?
In the respiring tissue
O2 dissociates (releases) from oxyhaemoglobin
This is called dissociation or unloading
Oxygen can then diffuse out of the erythrocytes and to the respiring cells
What do we mean by the term association?
Oxygen binds to haem group of haemoglobin to maintain concentration gradient
This is known as association or loading
Describe what happens to the dissociation curve when partial pressure of oxygen is low
- low partial pressure of oxygen
- increases affinity of haemoglobin for oxygen
- increases association of haemoglobin for oxygen
- decreases dissociation of haemoglobin for oxygen
- curve shifts to the left
Describe what happens to the dissociation curve when partial pressure of oxygen is high
- high partial pressure of oxygen
- decreases the affinity of haemoglobin for oxygen
- increases the dissociation of haemoglobin for oxygen
- therefore more oxygen is released to the respiring cells for respiration
- curve shifts to the right
Describe the effect of CO2 on O2 dissociation when CO2 increases (Bohr effect)
- increased CO2 (more acidic)
- decreases the affinity of haemoglobin for oxygen
- increases dissociation for oxygen
- more oxygen is released to respiring cells for respiration
- curve shifts to the right
Describe the effect of exercise on O2 dissociation
- during exercise, more CO2 produced
- decreases the affinity of haemoglobin for oxygen
- therefore it increases the dissociation of haemoglobin for oxygen
- therefore more oxygen is released to the respiring cells for respiration
- curve shifts to the right
What do we mean by the term affinity?
Means to attract
What is the formula for % saturation?
Percentage saturation of haemoglobin with oxygen = (oxygenated haemoglobin) / (maximum saturation) x 100
Explain why on the oxygen dissociation curve, the curve plateaus below 100%
After the first oxygen molecules associates, the conformation (shape) of the haemoglobin changes
Conformational change makes it easier for the 2nd and 3rd oxygen molecules to associate
It is difficult to associate a 4th oxygen molecule
- this is because the haemoglobin molecule becomes full
- and oxygen struggles to find a free binding site
Describe the partial pressure of oxygen at high and low altitudes
High altitude - low O2 partial pressure
Low altitude - high O2 partial pressure
