Lecture 20- Blood gas transport Flashcards
What is Dalton’s Law?
The total pressure is the sum of partial pressures exerted by each gas in the mixture
How does the percentage of O2 in the air change at different altitudes?
The total pressure changes. The percentage of O2 stays the same.
What is Henry’s Law?
The amount of gas that is dissolved in water is determined by solubility in water and the partial pressure in air.
pp in air is proportional to solubility in water
What percentage of O2 travels in the blood plasma?
3% plasma
97% haemoglobin
What is haemoglobin saturation?
The percentage of haem units that are combined with O2.
What values of haemoglobin saturation would be expected
- systemic tissue
- The alveoli
- 70-75%
- 100%
The binding of oxygn to Hb is affected by which 4 factors?
- PO2
- Blood pH
- Temperature
- State of O2 binding of the Hb molecule
What does th Bohr shift describe?
- Increase in CO2
- Deecrease in pH
- Curve shifts to right
- O2 unloads more easily
Which factors make the oxygen dissociation curve shift to the right?
C.A.D.E.T.
- CO2
- Acidic
- 2,3-DPG
- Exercise
- Temperature
When oxygen binds with haemoglobin it forms oxyhaemoglobin. What other types of Hbs are there?
Carboxyhaemoglobin
Methaemoglobin
Fetal Haemoglobin- 2 alpha and 2 gamma. Higher affinity for oxygen allows foetus to get oxygen.
How does CO2 travel in the blood?
- Carbonic acid H2CO3^- . 70%
- Carbaminohaemoglobin 23%
- Plasma 7%
What is the Haldane effect?
CO2 is unloaded in the lungs and picked up in respiring tissues.
Oxygenated Hb has a lower affinity for H+ ions. So decreased buffering power, releases H+.
Deoxygenated Hb has higher affinity so more buffering power- increased H+ uptake
Why is the O2 partial pressur lower in the alveoli than in the air?
O2 alveoli= 100 mmHg. The water humidifies it, More water in the lungs.
At sea level 159. at alveoli 100 mmHg.
