Gas transport in the blood Flashcards
Where does blood transport oxygen to and from?
From the lungs to the tissues
Where does the blood transport CO2 to and from?
From tissues to lungs for removal
Name the two forms in which oxygen travels in the blood.
In solution in plasma
Bound to haemoglobin protein in RBC’s
How much oxygen travels in the plasma?
Very little- 3ml O2 /litre of plasma
How much O2 is there/litre of whole blood?
200ml
How much of the 200ml is bound to haemoglobin?
197ml
What is the bulk of CO2 transported in?
In plasma (77%)
How is the other 23% of CO2 transported?
Haemoglobin
What is the partial pressure of oxygen in the alveoli the same as?
The partial pressure of the plasma, at the point where equilibrium has been met.
Which is more soluble in water; oxygen or CO2?
CO2
How many haem groups does a molecule of haemoglobin have?
4
What does each haem group have?
One Fe2+ which binds to an oxygen molecule
How many molecules of oxygen does one haemoglobin molecule bind to?
Four
What is the major determinant of the degree in which haemoglobin binds/is saturated with oxygen?
Partial pressure of oxygen in the blood.
What is the partial pressure of oxygen is systemic arterial blood?
100ml mercury
What is the amount of oxygen carried by haemoglobin determined by?
The amount of oxygen in the plasma (partial pressure of O2 in the plasma).
What is the amount of oxygen in the solution of plasma is determined by?
Partial pressure of O2 in the alveoli.
What is the partial pressure of oxygen in the alveoli determined by?
Alveolar ventilation
How much oxygen can we deliver to our tissues every minute?
How much of this oxygen is used?
1000ml
250ml
Define anaemia xoxox
YAY
any condition where the oxygen carrying capacity of the blood is compromised.
Name three ways an individual may get anaemia xoxo
Iron deficiency
Haemorrhage
B12 defiviency
List the four factors which may alter the affinity of haemoglobin for oxygen.
pH
Temperature
PCO2 (partial pressure)
DPG
If the body needs more oxygen, what will happen to pH, temperature and PCO2 in order for the body to get access to the 75% of oxygen it does not usually have access to?
Lower pH
Increase temperature
Increase PCO2.
What happens if we increase pH and decrease temp and PCO2?
Haemoglobin’s affinity for oxygen increases and hangs onto it more tightly and will not give any to the peripheral tissues.
What is DPG a by product of?
The metabolism of red blood cells