Respiratory Mechanics Topic 3 – Midterm

Question 1

Which artery carries deoxygenated blood

Answer 1

the pulmonary artery

Question 2

how is the process of expiration occur in the Chest Wall

Answer 2

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.

Question 3

how does a collapsed lung occur

Answer 3

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

Question 4

what is the pleural space

Answer 4

Double-walled, closed sac that separates each lung from the thoracic wall

Pleural cavity(Inside the pleural space): Interior of plural space

Question 5

what is the pleural space filled with

Answer 5

Intrapleural fluid

Secreted by surfaces of the pleural
Lubricates pleural surfaces

Question 6

where is the visceral pleura located

Answer 6

Attached to the lung outer surface

Question 7

where is the parietal pleura located

Answer 7

Attached to thoracic wall and diaphragm

Question 8

DRAW out pleural space to get a better understanding of it

Question 9

what are the Four different pressure considerations important in ventilation

Answer 9

Atmospheric (barometric) pressure
Alveolar pressure
Pleural pressure
Transpulmonary pressure

Question 10

what is Atmospheric (barometric) pressure

Answer 10

the measurement of air pressure in the atmosphere

Question 11

what is Alveolar pressure

Answer 11

Pressure inside alveolar sac

Question 12

what is Pleural pressure

Answer 12

Pressure of the fluid in the intrapleural space

the pressure surrounding the lung, within the pleural space

Question 13

what is Transpulmonary pressure

Answer 13

Transpulmonary pressure is the difference between the alveolar pressure and the intrapleural pressure in the pleural cavity.

Associated with lung recoil pressure

Question 14

Pressure moves from a __________ pressure to a __________pressure

Answer 14

high
low

Question 15

In the lungs we use ___________as a unit of pressure

Answer 15

“cmH2O”

Question 16

Intrapleural pressure is typically _____________

Answer 16

negative

Question 17

During resting breathing intrapleural pressure averages

Answer 17

-5cmH2O

Question 18

why is Intrapleural pressure typically negative

Answer 18

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

Question 19

what is transmural pressure gradient

Answer 19

difference between intrapleural and alveolar pressure.

Question 20

The pressure within an alveolus is always ____________than the pressure in the surrounding ______________ except when the volume has been reduced to zero.

Answer 20

greater
interstitial tissue

Question 21

By increasing lung volume, the transmural pressure gradient steadily ______________

Answer 21

increases

Question 22

What Determines Pressure with regards to “air”:

Answer 22

Volume (size of “container”)
Temperature: constant for breathing
Number of molecules

Question 23

what is Boyle’s Law

Answer 23

P1V1=P2V2

Question 24

what is poiseuille’s law of flow(write it out)

Answer 24

F = (change in)pressure/flow resistance

Question 25

what is needed to make air move

Answer 25

change in pressure

Question 26

how does alveolar pressures work during inspiration and expiration

Answer 26

During inspiration, the diaphragm and intercostal muscles contract, causing the chest cavity to expand and increasing the volume of the lungs.

This increase in lung volume decreases the pressure within the alveoli relative to the atmospheric pressure, which results in air flowing into the lungs from the outside environment

The air pressure within the alveoli becomes positive, causing the lungs to inflate.

During expiration, the diaphragm and intercostal muscles relax, causing the chest cavity to decrease in size and decreasing the volume of the lungs.

This decrease in lung volume increases the pressure within the alveoli relative to the atmospheric pressure, which results in air flowing out of the lungs and into the outside environment.

The air pressure within the alveoli becomes negative, causing the lungs to deflate.