Lecture 3 Resp (Post Quiz 1) Flashcards
What are some large qualities of the lungs that allow gas exchange to occur extremely quickly?
140ml of blood is spread over 800ft2 (entire surface area of respiratory membrane), combined with the short transcapillary distance the gasses have to travel, make this task easy.
What phenomenon allows blood in pulmonary capillaries to physically exchange gasses between them and the capillary endothelium?
The diameter of an RBC is larger than the diameter of pulmonary capillaries (they are squeezed through and exchange occurs through direct contact)
Will emphysema and a removed lung increase or decrease gas diffusion rate?
decrease
Will pulmonary edema and fibrosis causing diseases increase or decrease gas diffusion rate?
decrease
How does emphysema decrease gas diffusion rates?
It alveolar surface area
What is the diffusion coefficient?
A number relative to 1, that is a function of an individuals molecular weight and solubility
(02 is 1, co2 is 20)
What is diffusion capacity?
The volume of a gas that diffuses through the membrane vs. change in 1mmHg of partial pressure of that molecule, in 1 minute
What increases diffusion capacity?
Metabolic demand…exersize! (can increase it upto 3 times)
In what pathology would the V/Q ratio = 0, where there is not ventilation to the area?
Obstruction of teminal bronchiole (foreign or not) (zero V value)
In what pathology would the V/Q ratio = null, where there is no perfusion to the pulmonary capillaries to pickup alveolar 02?
Pulmonary Embolism
zero Q value
What is the physiologic shunt?
Analogous to dead space in lungs, it is blood that travels through pulmonary system that does not get oxygenated because ventilation is decreased
What is physiologic dead space?
Perfusion is decreased, air flows in the alveoli, but no gas exchange happens (mechanical obstruction to the alveolar membrane)
