47R. Respiratory Mechanics

Question 1

what are the 2 mechanics of breathing

Answer 1

1. the forces that move the lung and the chest wall
2. The resistance that they overcome

Question 2

what is PALV

Answer 2

alveolar pressure

Question 3

what is Pp

Answer 3

Interpleural pressure

Question 4

what is PATM

Answer 4

atmospheric pressure

Question 5

The forces that move the lung and the chest wall are aided by what two things

Answer 5

elastic properties - compliance and elastance

pressure gradient - PALV, Pp, PATM

Question 6

what are The resistances that they overcome

Answer 6

air- liquid surface tension

elastic properties of alveolar walls

airway radius

Question 7

what is compliance

Answer 7

is a measure of the distensibility of the lung

Question 8

what is the compliance equation

Answer 8

Comp= 1 divided by elastance

Question 9

what is elastance

Answer 9

the tendency of the lung to return to its original size when distended

Question 10

what is elastic recoil pressure

Answer 10

the measure of elastase

Question 11

When compliance increases, elastic recoil ……………

Answer 11

decreases

Question 12

When compliance decreases, elastic recoil …………..

Answer 12

increases

Question 13

when are respiratory muscles at rest (mention lung volume)

Answer 13

end of quiet exhalation
lung volume is FRC (functional residual capacity)

Question 14

what pressure is along the tracheobronchial tree

Answer 14

atmospheric

Question 15

in static conditions is there airflow

Answer 15

no

Question 16

Chest wall favours inflation/deflation

Lungs favour inflation/deflation

choose the correct word for each.

Answer 16

inflation

deflation

Question 17

describe the forces during inspiration and what happens

Answer 17

Muscle Contraction: Inspiratory Muscles: The diaphragm and intercostal muscles contract. This causes the chest to expand.

Pressure Changes: PALV (Alveolar Pressure): The pressure inside the alveoli (air sacs in the lungs) becomes lower than the atmospheric pressure (sub-atmospheric).

Air Flow: Into Lungs: Because the pressure inside the lungs is lower than outside, air flows into the lungs.

Question 18

describe the forces during expiration and what happens

Answer 18

Muscle Relaxation: Inspiratory Muscles: The diaphragm and intercostal muscles relax.

Recoil of Lungs: Elastic Recoil: The lungs naturally spring back to their original size.

Pressure Changes: The pressure inside the alveoli (PALV) becomes higher than the atmospheric pressure (PATM).

Air Flow: Out of Lungs: Because the pressure inside the lungs is higher than outside, air flows out of the lungs.

Question 19

what is frictional resistance of the airway determined by? And does this change depending on lung volume

Answer 19

flow
and no

Question 20

pressure flow characteristics are described by what equation

Answer 20

R = deltaP/V. = (8)(n)(l)/(pi)(r)^4

Delta P = pressure difference
V= flow rate
n= viscosity
l=length of tube
r= radius

Question 21

what are the 3 resistance types

Answer 21

1. Airway - entire airway
2. Parenchymal- lungs and airways combined
3. Chest wall - chest wall and abdominal structures

Question 22

In parallel tubes, total resistance is ……..than the resistance of the individual tubes

Answer 22

less

Question 23

The greatest resistance to flow occurs in the ……. ……. airways

Answer 23

medium-sized

Question 24

Parasympathetic stimulation causes bronchoconstriction / bronchodilation

Sympathetic stimulation causes bronchoconstriction / bronchodilation

Answer 24

Parasympathetic stimulation causes bronchoconstriction and sympathetic stimulation causes bronchodilation

Question 25

what are the muscles of (passive) quiet inspiration

Answer 25

diaphragm external intercostals

Question 26

what muscles are used in (passive) expiration

Answer 26

none - relies on passive recoil of lung tissue

Question 27

when do you do active breathing

Answer 27

exercise/severe obstruction/ hyperventilation

Question 28

what kind of muscles are used in active inspiration and can you name them (3)

Answer 28

accessory muscles 1. sternocleidomastoid 2. Scalenes 3. Pectoral Muscles

Question 29

what muscles are used in active expiration

Answer 29

abdominal muscles: - abdominus rectus - transverse abdominus Internal intercostal

Question 30

what is tidal volume

Answer 30

volume of air entering or leaving the lungs during a single breath

Question 31

what is Inspiratory Reserve Volume

Answer 31

extra volume of air that can be maximally inspired over an above typical resting tidal volume

Question 32

what is expiratory reserve volume

Answer 32

extra volume of air that can actively expired by maximal contraction beyond the normal volume of air

Question 33

what is residual volume

Answer 33

minimum volume of air remaining in the lungs even after a maximal expiration

Question 34

what are the average values/amounts of TV, IRV, ERV, RV

Answer 34

TV - 0.5 L IRV - 3.0 L ERV - 1.0 L RV - 1.2 L

Question 35

Which static lung capacities are a product of at least two lung volumes = IC

Answer 35

Inspiratory Capacity = IRV + TV Maximum volume of air that can be inspired at the end of a normal quiet expiration 3.5L

Question 36

Which static lung capacities are a product of at least two lung volumes = FRC

Answer 36

Functional Residual Capacity = ERV + RV Volume of air in lungs at end of normal passive expiration 2.2 L

Question 37

Which static lung capacities are a product of at least two lung volumes = VC

Answer 37

Vital Capacity = IRV + TV + ERV Max volume of air that can be moved out during a single breath following a maximal inspiration 4.5 L

Question 38

Which static lung capacities are a product of at least two lung volumes = TLC

Answer 38

total lung capacity = VC + RV total volume of air the lungs can hold

Question 39

Volume time curve - allows you to determine: what?

Answer 39

- Forced Vital Capacity (FVC): maximum volume that can be forcibly expelled from the lungs following a maximum inspiration - Forced Expiratory Volume in one second (FEV1): volume of air that can be expired during the first second of expiration in an FVC (Forced Vital Capacity) manoeuvre - FEV1/FVC ratio: The proportion of the Forced Vital Capacity that can be expired in the first second = (FEV1/FVC) X 100% - Normally more than 75%

Question 40

what are the 2 types of lung disease

Answer 40

obstructive and restrictive

Question 41

describe obstructive lung diseases and give examples

Answer 41

reduced expiratory flow and air trapping - asthma - COPD Increased TLC, RV and FRC

Question 42

describe restrictive lung diseases and give an example

Answer 42

reduced functional volume of the lung - Interstitial lung diseases - like fibrosis Reduced TLC, RV and FRC

Question 43

what is COPD

Answer 43

Chronic Obstructive Pulmonary Disease abnormal inflammatory response of the small airways to noxious particles or gases

Question 44

name 2 main conditions of COPD

Answer 44

emphysema and Chronic bronchitis

Question 45

what is chronic bronchitis

Answer 45

excessive mucus production and inflammation of bronchial tubes

Question 46

what is emphysema

Answer 46

destruction of alveolar wall and airway enlargement and reduced surface area for gas exchange

Question 47

what is asthma

Answer 47

a chronic inflammatory process, a reversible airway obstruction, hyperresponsiveness, airway remodeling - hypertrophy, hyperplasia and fibrosis. Bronchoconstriction-> increased airflow resistance -> difficulty with expiration

Question 48

what is pulmonary fibrosis

Answer 48

thickening and scarring of the interstitium (the tissue around the air sacs) of the alveolar walls.

Question 49

what causes pulmonary fibrosis

Answer 49

excessive deposition of collagen in the lung extracellular matrix

Question 50

In pulmonary fibrosis what does scarring result in and what is the name for this

Answer 50

multiple air-filled cystic spaces formed by dilated terminal and respiratory bronchioles (honeycomb lung).