Exam 2 Lecture 12 (3-9-23) Do-over Pulmonary Lecture, Spirometry, V/Q Matching (Andy's Cards) Flashcards
What could be causing the slow slope of the inspiration curve (black dashed line)?
If we have a lack of surfactant, it becomes difficult to put air into the lungs. And what happens when we get down to very low lung volume, usually our surfactant level decreases. And the longer the lung is collapsed or at very low lung volumes, the lower our surfactant concentrations go.
The surfactant that floats around in our alveolar fluids typically has a _______ shelf life.
short
What are type II alveolar cells?
Alveolar cells that produce surfactant
What are type I alveolar cells?
These cells are thin and cover a lot of surface area on the alveoli. They are responsible for gas exchange.
During normal breathing, inspiration will generate negative alveolar pressure. What effect will this cause on the surfactants lining the alveoli?
The negative alveolar pressure will cause the surfactant to be knocked loose. This will cause the lungs to replace the lost surfactant.
If the lungs are deflated and don’t have enough negative alveolar pressure, less surfactant will be knocked loose and replaced.
In terms of the proportions that make up the elastic recoil of a healthy lung.
_______ of recoil is based on the connective tissue of the lungs.
________ of recoil is based on surface tension.
What will happen to the surface tensions if the lungs lack surfactant?
one-third (connective tissue)
two-thrid (surface tension)
If the lungs lack surfactant, surface tension will play an even larger role in elastic recoil (increased proportion). This will also make it very difficult to fill the alveoli with air.
Does positive pressure ventilation affect that process of replacing surfactant?
Yes.
Does positive pressure ventilation affect that process of replacing surfactant?
Yes.
Alveolar pressure has to be negative to normally jar some surfactant loose. Breathing on an artificial ventilator is not the same as somebody who’s breathing on their own. With long term vent use, lungs usually start to misbehave.
(52:00)
For this graph, why does it require less transpulmonary pressure to fill the lungs up with saline than with air?
The saline filled lungs has a greatly reduce level of surface tension due to a decrease in air-water interface. All the air has been massaged out of the lungs before it was fill with saline. This results in a more compliant lung. (54:00)
Compare the hysteresis of the saline filled lung with air filled lung in this graph.
There is no hysteresis with saline filled lung. The lung behaves the same during inspiration vs expiration. For the air filled lung, there is less compliance during inspiration and more compliance during expiration.
What cell in the alveolus non-selectively engulfs and destroy pathogens and surfactants?
Alveolar Macrophage (60:00)
What is the function of spirometry?
What is the limitation simple spirometry?
Spirometry can measures air movement in and out of the patient.
Spirometry can not measure RV or any capacities that involve RV such as FRC and TLC. (73:00)
What indicator is used as a diagnostic measurement of FRC?
How does it work?
Helium (The system usually contains about 10% He)
The test starts with a known concentration of Helium and known volume in the deluxe spirometer system. The patient then takes a few normal breaths in the spirometer to allow Helium to diffuse to the lungs. This will result in a new concentration of He, which can be used to calculate FRC.
(Refer to min 81:00 for math)
What were the inert noble gases mentioned in this lecture?
He, Ne, Ar, Kr, Xe, and Rn
What is the second leading cause of lung cancer in the US?
Radon
What part of the house is more likely to be exposed to Radon?
Radon can pass from the soil to the air in a gaseous form and enter your home. Because your basement is below ground, it’s the first room that radon gas will reach as it rises from the soil to the air. Therefore, the concentration of radon gas in your basement will likely be higher than in any other room of your house.
Surface tension is ____________ to elastic recoil.
proportional
Surfactant Metabolism: After synthesis in ER and alterations in the Golgi Apparatus, surfactant is packed in multivesicular bodies and stored in the ____________ of type II alveolar cells.
Lamellar Bodies (96:30 and Lange)
What is normal alveolar ventilation (VA)?
What is normal perfusion to the lungs?
What is the normal V/Q ration?
VA= 4.2 L/min
Q= 5 L/min
4.2:5 = 0.84 *
“V/Q ratio about 0.8”- Dr. Schmidt
Which alveolus depicts normal V/Q matching?
Alveolus A is normal.
PAO2 = 100 mmHg
PACO2 = 40 mmHg
Which alveolus depicts airway obstruction? What could be an example of this?
What would gas conditions in the alveolus be equal to?
Alveolus B is depicting airway obstruction. Marble stuck in the mainstem bronchus .
Gas conditions in the alveolus should be equal to mixed venous blood.
PAO2 = 40 mmHg
PACO2 = 45 mmHg
Which alveolus depicts blood flow obstruction? What could be an example of this?
What would gas conditions in the alveolus be equal to?
Alveolus C is depicting blood flow obstruction. Pulmonary Embolus.
Gas condition in the alveolus should be equal to inspired gas.
PAO2 = 150 mmHg
PACO2 = 0 mmHg
Which alveolus wil have a V/Q ratio of zero?
Alveolus B will have a V/Q of zero.
There will be normal perfusion, but no ventilation.
What will be the V/Q ratio of Alveolus C?
If there is normal ventilation, but no perfusion. V/Q ratio comes up as an “ERROR” on the calculator, because the ratio is pretty much infinity. (103:00)
