Exam 2 - Lecture 5 Flashcards
What is the lower error bar for upright, and what is the upper error bar for supine?
2.6ish -> 2.4ish, thats why positioning may OR may not be statistically significant for every patient.
what is higher, ERV or IRV?
IRV
What makes up vital capacity?
ERV, IRV, TV
What can basic spirometry not cover?
Anything that has RV as a component. So RV, FRC and TLC.
What is the indicator gas USUALLY for advanced spirometry? why?
Helium; cheap and inert and theres very low volumes of it in the atmosphere so makes it more accurate to measure.
Do not want to use a gas that is going to undergo any reactions in the lung or be exchanged.
How do they measure FRC?
With advanced spirometry, they compare starting concentration with end concentration.
No helium is lost, it’s just diluted out
What do you need to use advanced spirometry?
Helium (indicator gas), helium meter, source of oxygen, and CO2 absorbent.
What group did he talk about on the periodic table?
noble gases
Whats at the top of noble gases?
helium.
What other noble gases did he mention you can use as an indicator gas?
Neon, Argon (expensive and rare), Xenon, Radon
What did he say about radon gas?
It isnt reactive, but natural radon in the ground is very reactive. Radon gas is the second leading cause of Lung cancer behind smoking, and can be present in basements up north.
Emphysema leads to what issues with compliance?
Loss of elastic tissue, becomes much more compliant with low resistance.
Emphysema is more or less stretchy?>
He said LESS. It’s confusing, but i believe the lack of stretchiness is related to lack of recoil. it expands just fine, just doesnt recoil well and exhale air.
How much transpulmonary pressure do you need to expand with emphysema, starting at RV?
only 10 cmH2O to get to nearly 6L of vital capacity.
Restrictive lung diseases such as fibrosis have more or less compliance?
Less, harder to fill.
What gets “laid down” in the lungs with fibrosis?
Scar tissue
Fibrosis causes what shift on the chart, and what does that mean?
Right shift, more pressure is required and end up with less Vital capacity.
Starting at RV, how much pressure is needed to get to what total vital capacity with fibrosis?
35cmH2O is required to only get 3L of vital capacity.
What do normal lungs require for pressure and vital capacity starting at RV?
4.5L with a transpulmonary pressure of 30cmH2O
At the beginning of inspiration from RV, the PTP change between 0 and 8cmH2O alters the volume of the lung how?
Doesnt change much, but once it gets above 8, volume increases fast.
What would if we hypothetically put all saline into the lungs?
Way more compliant with nearly zero hysteresis.
If saline causes there to almost be no hysteresis, that tells us that something about air is affecting the
surface tension.
whats the air-water interface
Where air and a very thin layer of water meet eachother.
If we have a ton of surface tension, this makes it more or less difficult to get air into lungs?
Much more difficult.
When we replace air with saline, the air-water interface is
removed from the lungs
Surface tension has a big influence for inhalation of air, especially at
low lung volumes.
This is why there is such low lung compliance between 0-8cmH2O
What is the role of surfactant
Gets in between water molecules and breaks surface tension, making it easier for air to get into lungs.
Surfactant is made out of
90% phospholipids, and 10% 4 different surfactant proteins.
The 4 surfactant proteins are ______, and which ones are hydrophillic?
A B C and D
A and D are hydrophillic, B/C are hydrophobic.
Surfactant proteins are a mix of water soluble and insoluble, so they are
amphipathic
how do you spell the super long phospholipid and how many syllables is it
what % of surfactant does it make up?
Dipalmitoylphosphatidylcholine
10 syllables.
31%
Unsaturated phosphatidylcholines make up __% of surfactant?
31%
What cells produce surfactant?
Mostly type II and clara/club cells, and a little bit of goblet cells
Where are goblet cells located and what do they produce?
mostly mucus, a little surfactant.
Where are club/clara cells located?
bottom part of airways/in alveoli
what shape are type II cells? why?
Cube shaped so they can fit extra stuff such as golgi apparatus and allat shit
Type II cells are between _______
interspersed between type I cells.
Surfactant is released by
exocytosis
Major gas exchange happens in ________ at what %?
Type I cell, 90-95% of gas exchange.
What % of gas exchange occurs by type II cells?
5-10%
There are ___ as many type II cells than type I.
2x
but type I takes up more space cause theyre long and skinny
Whats the crosshatched netting structure called and what does it do?
Tubular myelin
Where surfactant hangs out while its inactive, until it gets knocked off by vacuum pressure from air moving in, then it floats up to air-water interface to become active and break surface tension.
What is an issue with surfactant and positive pressure ventilation?
The lack of vacuum pressure doesnt knock off as many surfactant off tubular myelin to become active.
What breaks down old surfactant that isnt good anymore and what does it do with them?
Alveolar macrophages, turns them into component parts to be reuptaken by surfactant producing cells to recycle and make good again.
They also clean up any garbage in lungs.
If we arent reproducing more surfactant, surface tension will
increase
There needs to be a ______ between rate surfactant falls apart and replaced.
balance
it could also just not be getting knocked off net, same issues
There is _______ where lungs are collapsed.
no surfactant
If there is no surfactant where lungs are collapsed, what issue does this cause?
Hard to get it back open and re-recruit, because surfactant isnt breaking up surface tension.
What is important for re-opening collapsed lung areas?
Time.
Much harder to re-open if its been a day instead of just 30 minutes.
What cells release a mediator that irritates the airway, causing airway smooth muscle to tighten?
Mast cells releasing histamine
How many alveoli do we have as young adults?
500 million.
Can your lungs reproduce alveoli?
Yes, but at a very slow rate (just like the heart)
Each alveoli has up to _______ capillaries.
a thousand
how many square meters of surface area is available in the lungs for gas exchange in a healthy 20 year old adult, and what is that size compared to?
70 square meters, tennis court.
Water surface tension is responsible for ______ of recoil pressure, while elastic tissue of the alveoli are responsible for ___.
2/3rds; 1/3rd
Water wants to be ___ other water.
near
What disorder has “tons” of springy tissue? what are the issues this causes?
Fibrosis/RLD. Hard to inflate, increased resistance, decreased compliance, easy to exhale.
More negative pressures required.
There is a ______ in every lung disease ever studied.
Surfactant deficiency
Surfactant not only reduces surface tension but also keeps our lungs ___.
dry
Surfactant keeps the water layer ____, because this helps with gas exchange.
thin
At higher lung volume, air resistance is
low
At lower lung volume, air resistance is
high
Just think of it like blowing up a balloon. Hard to start, but once its open, its easy.
Large vessels are held open by ______, but it also holds our _______ ________.
Negative pleural pressure; larger airways open.
At the level of the alveolus (small airways), the thing that keeps it open is more related to ______ than the negative intrapleural pressure.
volume
What is traction?
Negative pleural pressure holding the larger airways open, allowing for air to come in.
