Respiratory Mechanics Topic 3 – Midterm Flashcards
Which artery carries deoxygenated blood
the pulmonary artery
how is the process of expiration occur in the Chest Wall
Onset of expiration begins with relaxation of inspiratory muscles
Relaxation of diaphragm and muscles of chest wall, plus the elastic recoil of the alveoli, decrease size of the chest cavity
Intrapleural pressure increases; lungs compressed
Intra-alveolar pressure increases
When pressure increases to above atmospheric pressure, air is driven out and expiration occurs.
how does a collapsed lung occur
occurs when air escapes from the lung.
The air then fills the space outside of the lung between the lung and chest wall.
This buildup of air puts pressure on the lung, so it cannot expand as much as it normally does when you take a breath
what is the pleural space
Double-walled, closed sac that separates each lung from the thoracic wall
Pleural cavity(Inside the pleural space): Interior of plural space
what is the pleural space filled with
Intrapleural fluid
Secreted by surfaces of the pleural
Lubricates pleural surfaces
where is the visceral pleura located
Attached to the lung outer surface
where is the parietal pleura located
Attached to thoracic wall and diaphragm
DRAW out pleural space to get a better understanding of it
what are the Four different pressure considerations important in ventilation
Atmospheric (barometric) pressure
Alveolar pressure
Pleural pressure
Transpulmonary pressure
what is Atmospheric (barometric) pressure
the measurement of air pressure in the atmosphere
what is Alveolar pressure
Pressure inside alveolar sac
what is Pleural pressure
Pressure of the fluid in the intrapleural space
the pressure surrounding the lung, within the pleural space
what is Transpulmonary pressure
Transpulmonary pressure is the difference between the alveolar pressure and the intrapleural pressure in the pleural cavity.
Associated with lung recoil pressure
Pressure moves from a __________ pressure to a __________pressure
high
low
In the lungs we use ___________as a unit of pressure
“cmH2O”
Intrapleural pressure is typically _____________
negative
During resting breathing intrapleural pressure averages
-5cmH2O
why is Intrapleural pressure typically negative
negative because of the mechanical properties of the lungs and the chest wall;
The former wants to collapse and the latter expand, creating the negative pressure
what is transmural pressure gradient
difference between intrapleural and alveolar pressure.
The pressure within an alveolus is always ____________than the pressure in the surrounding ______________ except when the volume has been reduced to zero.
greater
interstitial tissue
By increasing lung volume, the transmural pressure gradient steadily ______________
increases
What Determines Pressure with regards to “air”:
Volume (size of “container”)
Temperature: constant for breathing
Number of molecules
what is Boyle’s Law
P1V1=P2V2
what is poiseuille’s law of flow(write it out)
F = (change in)pressure/flow resistance
