Question

Define partial pressure. What is the partial pressure of oxygen (PO2) in the outside air, in the alveoli, in the pulmonary vein, and after the tissue (i.e. muscle)? What is the cause of the drop on PO2 at each of these places? What is the partial pressure of CO2 (PCO2) in the arterial blood after an exhalation and then after the muscles? What causes the PCO2 to go up from the lungs to after the muscles?

Answer 1

Partial pressure:

Pressure that would be exerted by one of the gases in a mixture if it occupied in the same volume on its own.

1. Partial pressure of oxygen outside the air = 0.21× 760= 160mm.hg

2. Partial pressure of oxygen in alveoli= 104 mm.hg

3. Partial pressure of oxygen in pulmonary vein= 100mm.hg

4. Partial pressure of oxygen in muscles = 45mm.ng

II.Drop in po2

1. Lung damage due to trauma.

2. COPD

3. Pulmonary edema

4. Respiratory failure

5. Respiratory distress syndrome.

III. PCO2 after exhalation = 40mm.ng

Pco2 after the muscles= 45mm.ng

IV. Pco2 level:

1. Hypercapnea.

2. Hypoventilation

3. Lung diseases

4. Respiratory failure