Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
MP - Lecture 26
Pulmonary Gas Exchange and O2 Transport
| Question | Answer |
|---|---|
| Medical Physiology – Lecture 26 | Pulmonary Gas Exchange and O2 Transport |
| Diffusion of O2 from air to blood consists of two reversible processes: | O2 diffusion from air to RBC interior and dissolved O2 binding to Hb |
| Both processes of O2 diffusion rapidly reach: | Equilibrium |
| At equilibrium, PO2 = | PO2 in air |
| At equilibrium, dissolved O2 and HbO2 depends on: | PO2 |
| P50 represents: | Pressure at which Hb is 50% saturated |
| P50 increase means O2 affinity: | Decreased (right-shift) |
| P50 can be increased by: | High temperatures, 2,3-DPG, high CO2, and low pH |
| Pulse oximeter measures: | Absorbance ratio at two different wavelengths (HbO2 and Hb) to determine saturation |
| Pulse oximter does not measure: | Arterial O2 content |
| O2 content depends on: | Hb saturation and amount |
| Hb saturation depends on: | PO2 and dissociation curve |
| O2 content (mL O2 / 100 mL blood) = | (1.34) x (Hb saturation) x (Hb content) |
| O2 content if 100% saturation and 15g/100 mL blood = | (1.34) x (1.0) x (15) = 20 |
| O2 content if PO2 = 26 mmHg and 15g/100 mL blood = | (1.34) x (0.5) x (15) = 10 |
| Amount of O2 dissolved in blood at PO2 = 100 is: | 0.3, minor contribution |
| Amount of dissolved O2 in blood at PO2 = 1000 is: | 3, significant contribution |
| Rate of diffusion between air and blood is proportional to: | Surface area |
| Rate of diffusion between air and blood is inversely proportional to: | Thickness of barrier |
| PO2 at the pulmonary capillary end equals: | PAO2 |
| CO2 partial pressure difference is smaller compared to O2, but same amount of diffusion because: | CO2 has higher solubility |
| Inspired air PO2 | 150 mmHg |
| Inspired air PCO2 | ~0 mmHg |
| Alveolar air PO2 | 100 mmHg |
| Alveolar air PCO2 | 40 mmHg |
| Why don’t alveolar PO2 and PCO2 not change with each breath? | They do but very subtle changes |
| Steady state and gas composition is determined by: | Alveolar ventilation |
| VCO2 = | (VA) x (PACO2/760) |
| Hyperventilation increases O2 content by: | Small increase |
| Hypoventilation causes: | PACO2 increase, PO2 decrease |
| Alveolar PO2 and PCO2 change in ___ direction with ___ magnitudes. | Opposite, similar |
| If O2 content and VA change by the same factor, PAO2 and PACO2: | Do not change |
| Alveolar Gas Equation | PAO2 = PIO2 – (PACO2/R), where R = 0.8 in balanced diet |
| During hypoventilation, supplemental O2: | Corrects hypoxemia, but not hypercapnia |
Created by:
emyang
Popular Physiology sets