Video 7 Pulmo Gas Exchange P1 Flashcards
Primary function of the lung
Gas exchange
What is the partial pressure of oxygen?
150 mmHg
Why is the alveolar gas partial pressure less than what is inspired?
it is a balance of the addition of PO2 by ventilation and the removal of PO2 by blood flow
Causes of hypoxemia
- hypoventilation
- diffusion limitation
- shunt
- Ventilation perfusion inequality
Hypoventilation _______ the level of PO2 and _______ the level of CO@
reduces
increases
All the expired CO2 comes from?
the alveolar gas
Describe the relationship between Alveolar ventilation and PCO2
inversely proportional
Alveolar gas equation
What is the partial pressure of CO2 under normal conditions?
40 mmHg
What are causes of hypoventilation
- brainstem injury
- drugs
- SC injury
- Nerve disease
- Changes in NMJ
- Muscular disease
- Chest injury
- Obstruction
What three events can cause diffusion limitation?
high levels of exercise, high altitude, lung disease that causes a thickened blood gas barrier
What is shunting?
blood reaching the arterial system without going through ventilated areas of the lung
T/F: Shunting is abnormal in the lung
False; there is always a small amount that enters the pulmonary circulation downstream of the pulmonary capillaries
where are thiebisian veins found?
in the myocardium
Diseases where shunting is important
AV anastamosis (one branch of PA drains to PV)
Patent ductus arteriosus
intraventricular septal defect
