Respiratory Mechanics

Question 1

The rib cage helps sustain _____ around the lung

Answer 1

negative pressure

Question 2

What is the main muscle of inspiration

Answer 2

diaphragm

Question 3

What role does the diaphragm have in expiration

Answer 3

little

Question 4

What happens if the diaphragm is paralyzed or if there is an abscess

Answer 4

accessory muscles hav eto employed

Question 5

The contraction of intercostal muscles is a clinical sign of what

Answer 5

dyspnea

Question 6

Visible contraction of scaleni and SCM is indicative of what

Answer 6

dyspnea

Question 7

What are the accessory muscles of inspiration

Answer 7

scaleni and SCM

Question 8

Normally, expiration is what type of process

Answer 8

passive

Question 9

What are the most important muscles of expiration

Answer 9

abdominal muscles

Question 10

What is the pleural pressure

Answer 10

pressure of the pleural fluid - normally is slightly negative

Question 11

What is the alveolar pressure

Answer 11

pressure of air inside the lung alveoli

Question 12

What happens to the pleural pressure during inspiration

Answer 12

expansion of chest cage pulls outward on lungs, creating more negative pressure

Question 13

What happens to the alveolar pressure during inspiration

Answer 13

falls slightly below atmospheric pressure in oder to pull air into aveoli

Question 14

What is transpulmonary pressure

Answer 14

difference between alveolar pressure and pleaurel pressure

message of elastic forces in lungs that tend to collapse the lungs

Question 15

What are some problems with alveoli that can cause pleural effusion

Answer 15

atelectasis

Question 16

Breathing sequence during inspiration

Answer 16

1. brain initaes
2. impulse goes to inspiratory muscles
3. diagraph contracts
4. thoarcic volume increases
5. intrapleural pressure become more negative
6. alveolar trasmural pressure gradient increases
7. alveoli expaind
8. alveolar pressure falls below atmosphere, establishing a pressure gradient for airflow

Question 17

Breathing sequence during expiration

Answer 17

1. brain ceases inspiratory command
2. inspiratory muscles relax
3. thoracic volume decreases, causing intrapleural pressure to become less negative and decreasing the alveolar transmural pressure gradent
4. decrease alveolar trasmural pressure allows increased alveolar elastic recoli
5. alveolar pressure increases above atmospheric pressure

Question 18

What is lung complicance/

Answer 18

extend to which the lungs will expand for each unit increase in transpulmonary pressure

Question 19

How is complicance related to elasticity

Answer 19

inverse

Question 20

How is compliance determed

Answer 20

elastic forces of lung tissue (elastin and collagen)

elastic forces of surface tension

Question 21

How is the pressure tending to collapse an alveolus related to surface tension

Answer 21

directly proportional

Question 22

Large alveolus has a _____ collapsing pressure

Answer 22

low

Question 23

small alveous will have a ______ collapsing pressure

Answer 23

high

Question 24

Function of surfactant

Answer 24

decreases surface tension on alveolar aqueous surface, prevents atelectasis

Question 25

Mechanism of action for surfactant

Answer 25

surfant molecules align on alveolar surface, intermolecular forces between surfactant molecules break up the attracting forces between liquid molecules ling the alveoli.

Question 26

What is infantile respiratory distress syndrome

Answer 26

neonates with ineffective lecthin, have respiratory distress upon delivery.

Question 27

At functional residual capacity what do the lungs want to do

Answer 27

collapse

Question 28

At functional residual capacity what does the chest wall want to do

Answer 28

expand

Question 29

What are the effects of increased lung compliance

Answer 29

``` loss of elastic fibers in lungs lung compliance increases steeper slope of pressure volume curve higher FRC barrel shaped chest ```

Question 30

What are the effects of decreased lung compliance

Answer 30

kyphosis | concave front chest (pectus excavatum)

Question 31

What is pumonary resistance

Answer 31

resistance to airflow

Question 32

How do you calculate resistance to airflow

Answer 32

(8 x viscosity of inspirted air x length of airway) / (pi x radius of airway ^4)