Pulmonary Mechanics Flashcards
From the trachea to the alveolar sacs, what happens to Cross Sectional Area? What about velocity?
it increases
velocity decreases
What is the flow of blood through the respiratory system driven by?
pressure gradients
Where do you have gas exchange?
in the respiratory zone, THERE IS NO gas exchange in the conducting zone
For inspired air to reach the alveoli, where exchange actually occurs, it must first pass through a network of (blank) .
branching airways
Each airway divides into (blank) daughter airways at each branching point. Each division is referred to as a generation. There are approximately (blank) generations of airways in the lung. The result is a “pulmonary tree”.
two
23
Airways within the lung can be divided into two functional domains, what are they?
conducting zone, and respiratory zone
What are the components of the conducting zone and what volume does it contain, does gas exchange occur here?
Is this the first 16 generations or the last 7?
trachea, bronchi, bronchioles, and terminal bronchioles
150 ml
No gas exchange (anatomical dead space)
First 16
What are the components of the respiratory zone? What is the functional unit of the respiratory zone?
What volume does it contain?
respiratory bronchioles, alveolar ducts, alveolar sacs
acinus
3,000 ml
The distance from terminal bronchiole to distal alveolus is only a few (blank)
mm
Lung volumes and how they are defined can be illustrated by the results obtained from the use of a (blank).
spirometer
Normal/relaxed breathing is referred to as (blank)
tidal volume
You still have volume in your lungs even after expiration, this left over is called (blank)
functional residual capacity
The difference between max inspiration and max expiration is called the (Blank)
vital capacity
(blank) is the volume following maximal inspiration
total lung capacity (TLC)
(blank) is the volume left after maximal expiration.
residual volume (RV)
(blank) is TLC-RV
vital capacity (VC=TLC-RV)
(blank) is the volume inspired under normal resting conditions
Tidal Volume (Vt)
(blank) is the volume remaining at end of normal tidal expiration
Functional Residual Capacity (FRC)
(blank) is the volume expelled during maximal forced expiration starting at the end of normal tidal expiration.
Expiratory Reserve Volume (ERV)
(blank) is the volume inspired during maximal inspiratory effort starting at the end of normal tidal inspiration.
Inspiratory Reserve volume (IRV)
(blank) is the volume inspired during maximal inspiration starting after at the end of normal tidal expiration.
Inspiratory Capacity (IC)
When you lay down, the contents of your abdomen push down on your diaphragm which reduces (blank)
functional residual capacity
ERV decreases as well and IRV increases
Which lung volumes cannot be measured with a spirometery? Why?
FRC, TLC, RV
no real zero
What are the three ways to measure FRC?
nitrogen dilution, helium dilution, plethysmography
How does nitrogen dilution work?
breath in 100% oxygen, all nitrogen gets out of your lungs which then can be measured to figure out FRC
How does helium dilution work?
put helium in and wait for equilibrium and solve for amount in lungs
How does plethysmography work?
Use boyles law and measure change in pressure while an individual is in a box
How does positive breathing work?
create gradient by blowing air into your lungs
How does negative pressure breathing work?
create pressure gradient by making inside more negative via boyle’s law. (make intrapleural space negative by increasing volume) This negative pressure will allow the outside air to be more positive so air will go into your lungs
What is the most important muscle for negative breathing?
diaphragm
When the (blank) contracts, the volume of the chest cavity increases, while the abdominal contents are forced down and forward.
diaphram
Beside the diaphragm, the (blank) muscles also contribute to inspiration by pulling the ribs upward, which expands the chest cavity.
external intercostal
(blank) muscles play a role in inspiration during conditions such as exercise or in patients with chronic obstructive pulmonary disease.
accessory
What are the two helpful accessory muscles for inspiration?
scalene muscles (which lift the first 2 ribs) Sternomastoid muscles (which raise the sternum)
Which is an active process and which is a passive process inspiration or expiration?
inspiration is active and expiration is passive
(blank) is normally a passive process during quiet breathing. The lung and chest wall are (blank) and tend to return to their equilibrium positions upon relaxation of the inspiratory mus
expiration
elastic
During conditions such as exercise, expiration can become (blank). The most important muscles for expiration are what?
active Abdominal (rectus abdominus, internal and external obliques, transversus abdominis) Internal intercostals pull their rib cage down
How do you find transpulmonary pressure?
transpulmonary pressure= alveolar pressure- intrapleural pressure
Is there a pressure gradient between alveolar pressure and atmospheric pressure? How is there a negative pressure in intrapleural space then?
no
Due to elastic recoil pressure which will allow for pressure gradient (transpulmonary pressure gradient)
At FRC alveolar pressure (PA) or the pressure inside the lungs is (blank) to the,atmospheric or barometric pressure (Pa)
equal
the intrapleural pressure (PIP) or the pressure in the space between the lungs and the chest wall is (blank) relative to the atmospheric pressure (PB).
As a results there is a (blank) (PL) gradient, which is the difference between the alveolar pressure (PA) and the intrapleural pressure (PIP).
negative
transpulmonary pressure
The (blank) reflects the elastic recoil properties of the lung and is sometimes referred to as the elastic recoil pressure.
transpulmonary pressure (PL)
Changes in lung volume are due to changes in the (blank)
transpulmonary pressure
Increase (blank) of chest cavity, reduce pressure, cause lung to expand due to elastic properties of chest wall and lungs, then that will decrease pressure in lungs which will then allow for a pressure gradient between atmosphere and lungs which will drive inspiration.
volume
changes in lung volume are due to changes in the (blank)
transpulmonary pressure
Changes in transpulmonary pressure are also associated with changes in the what?
transrespiratory pressure (Prs) and transthoracic pressure (Pcw)
What is the equation for transpulmonary pressure?
transpulmonary pressure (Pl)= alveolar pressure (PA)-intrapleural pressure (Pip)
What is the equation for transrespiratory pressure?
Prs=Alveolar pressure (PA)-atmospheric pressure (Pb)
What is the equation for transthoracic pressure (Pcw)?
Transthoracic pressure (Pcw)= intrapleural pressure (Pip)-atmospheric pressure (Pb)
Upon inspiration as you increase volume what happens to your intrapleural pressure? What happens to your flow? what happens to alveolar pressure?
becomes more negative
flow increases, reaches a peak and then decreases
Becomes more negative, peaks, then increases
As you decrease pressure you will increase (blank)
volume
The slope of a line on a pressure volume graph denotes what ?
compliance
Why don’t you want high compliance in the lung?
You don’t want high compliance because you want a change in pressure so that you can get exhalation and inhalation. In emphysema the compliance is increased and elastance is decreased.
Compliance is the inverse of (blank)
elastance (ΔP/ΔV)