Blood Supply, Gas Exchange, Ventilation and Perfusion Flashcards
What do the PULMONARY ARTERIES TRANSPORT?
Deoxygenated Blood, Away From the Heart, to the Lungs
What do the PULMONARY VEINS TRANSPORT?
Oxygenated Blood, From the Lungs, to the Heart
What TYPE of FLOW and PRESSURE exists in the PULMONARY CIRCULATION?
High Flow, Low Pressure System (Systolic Pressure ~25mmHg)
What is the PARTIAL PRESSURE of O2 in ALVEOLAR AIR (PAO2)?
100mmHg (13.3kPa)
What is the PARTIAL PRESSURE of O2 in the ARTERIAL BLOOD (PaO2)?
100mmHg (13.3kPa)
What is the PARTIAL PRESSURE of CO2 in ALVEOLAR AIR (PACO2)?
40mmHg (5.3kPa)
What is the PARTIAL PRESSURE of CO2 in the ARTERIAL BLOOD (PaCO2)?
40mmHg (5.3kPa)
What is the PARTIAL PRESSURE of O2 in MIXED VENOUS BLOOD (PVO2)?
40mmHg (5.3kPa)
What is the PARTIAL PRESSURE of CO2 in MIXED VENOUS BLOOD (PVCO2)?
46mmHg (6.2kPa)
The RATE of DIFFUSION across a membrane is:
1) Directly Proportional to the Partial Pressure Gradient
2) …to Gas Solubility
3) …to the Available Surface Area
4) Inversely Proportional to the Thickness of the Membrane
5) Most Rapid Over Short Distances
Which ALVEOLAR STRUCTURAL CHARACTERISTICS lend well to the diffusion process?
1) Large Surface Area
2) Thin Endothelial Membrane (Short Distance for Gas Exchange)
What is SHUNTING?
Passage of Blood Through Areas of the Lung that are Poorly Ventilated
When Perfusion Exceeds Ventilation in L/min
What is ALVEOLAR DEAD SPACE?
> PaO2 - Pulmonary Vasodilation
< PaCO2 - Bronchial Constriction
When Ventilation Exceeds Perfusion in L/min
What is ANATOMICAL DEAD SPACE?
1) Air in the Conducting Zone which is Unable to Participate in Gas Exchange
2) The Walls of the Airways are Too Thick (i.e. Nasal Cavities, Trachea, Bronchi and Upper Bronchioles)
What is PHYSIOLOGICAL DEAD SPACE?
Alveolar Dead Space + Anatomical Dead Space
