Waters II

Question 1

What is the major muscle of inspiration?

Answer 1

the diaphragm

Question 2

How much does the diaphragm move during tidal inspiration?

Answer 2

1cm down

Question 3

How much does the diaphragm move during forced inspiration?

Answer 3

up to 10cm

Question 4

What nerve innervates the diaphragm?

Answer 4

the phrenic nerve

Question 5

What accessory muscles help in inspiration?

Answer 5

• External intercostals (I for E and E for I),
• Scalenes, and
• SCM

Question 6

How does expiration occur normally?

Answer 6

passive (no muscles)

Question 7

How does forced expiration occur (what muscles?)?

Answer 7

abdominal muscles (rectus abdominus, internal and external obliques, transverse abdominus) and internal intercostals work

Question 8

What happens to intra-pleural pressure during inspiration?

Answer 8

it becomes more negative and transpulmonary pressure increases

Question 9

What is transpulmonary pressure?

Answer 9

Palveolar-Pintrapleural

Question 10

What does an increase in transpulmonary pressure cause?

Answer 10

increased lung expansion

Question 11

How does lung expansion affect Palveolar?

Answer 11

it becomes sub-atmospheric

Question 12

What happens when Palveolar becomes sub-atmospheric?

Answer 12

air flows into alveoli

Question 13

T or F. Pintrapleural becomes less negative during inspiration

Answer 13

F. It becomes more negative

Question 14

When is Palveolar most negative?

Answer 14

Mid-inspiration

Question 15

When is Palveolar most positive?

Answer 15

Mid expiration

Question 16

What happens with Palv- Patm is negative?

Answer 16

inspiration

Question 17

Why is Pintrapleural negative?

Answer 17

There is a natural tendency for the chest wall to pull out and for the lung tissue to collapse

Question 18

The degress to which transpulmonary pressure (Palv- Pip) leads to lung expansion depends on ____ of the lung.

Answer 18

compliance (compliance= 1/elasticity)

Question 19

T or F. Compliance changes during parts of inspiration (and expiration)

Answer 19

T. It is not constant or linear, nor is compliance the same during inspiration as it is during expiration

Question 20

Why do compliance patterns differ from inspiration to expiration?

Answer 20

hysteresis (surfactant properties control this)

Question 21

What pathologies can decrease compliance of the lungs (this is considered ‘restrictive’)?

Answer 21

• fibrosis
• pulmonary edema

these patients have trouble getting air IN to the lungs and EXPANDING them

Question 22

What pathologies can increase compliance of the lungs (‘this is considered obstructive’)?

Answer 22

• emphysema
• some in normal aging

these patients have trouble getting air OUT of the lungs

Question 23

When compliance increases, ____ becomes more likely

Answer 23

lung collapse

Question 24

T or F. Restrictive lung patients have decreases capacities and volumes (FVC, TLC, RV, FRC)

Answer 24

T.

Question 25

T or F. Obstructive lung patients have decreases capacities and volumes (FVC, TLC, RV, FRC)

Answer 25

F. Increases FRC, TLC, FEV1 and RV, but normal or reduced FVC

Question 26

What does the term COPD encompass?

Answer 26

emphysema or chronic bronchitis

Question 27

80-90% of COPD cases are caused by what?

Answer 27

smoking

Question 28

What happens in emphysema?

Answer 28

destruction of alveolar walls due to loss of elastic material (increased compliance) and enlargement of alveolar air spaces which decreases surface area for gas exchange

Question 29

What happens when elastic material is lost from lung tissue?

Answer 29

the lungs struggle to stay open during forced expiration

Question 30

What causes chronic bronchitis?

Answer 30

inflammation where the airways become obstructed due to excessive mucus production

Question 31

What changes are seen in Pip at the end of inspiration in emphysema patients?

Answer 31

less negative Pip than normal due to loss of elastic fibers

Question 32

Lung compliance is determined by what main factors?

Answer 32

- tissue properties | - surface forces

Question 33

What is interdependence?

Answer 33

The fact that adjacent alveoli share a wall prevents them from collapsing

Question 34

Tissue properties (collagen, elastin, etc.) account for approx. ___ of the compliance of the lung

Answer 34

1/3

Question 35

What is the role of pulmonary surfactant?

Answer 35

It acts as a detergent to reduce water molecule surface tension that tends to act to promote collapse of alveoli. NOTE: Surface tension must also be overcome to expand the lungs

Question 36

What produces surfactant?

Answer 36

Type II pneumocytes

Question 37

What stimulates surfactant production?

Answer 37

large expansion of the lungs

Question 38

What happens in respiratory distress syndrome (RDS) of newborns?

Answer 38

reduced surfactant production (which occurs late in gestation) makes lung inflation difficult

Question 39

T or F. Compliance is increased in RDS

Answer 39

F.

Question 40

What is another potential consequence of RDS

Answer 40

Alveoli tend to collapse upon expiration (aka atelectasis)

Question 41

How is RDS treated?

Answer 41

mechanical ventilation and surfactant replacement therapy

Question 42

What is the transmural pressure needed to keep an alveoli open?

Answer 42

2*Tension/radius of sphere Laplace's law

Question 43

Atelectasis is a common complication of anesthesia, why?

Answer 43

it reduced surfactant function

Question 44

Resistance to air flow decreases drastically in the respiratory airways compared to conducting airways even though radius decreases substantially. Why?

Answer 44

Because the cumulative radius is higher

Question 45

What is lateral traction?

Answer 45

elastic connective tissue fibers attach to airways exterior and pull outward, tending to open airways

Question 46

What happens in asthma?

Answer 46

bronchioles constrict via inflammation

Question 47

Where is Pip most negative in the lung?

Answer 47

at the apical parts

Question 48

Where is resistance to flow highest in the lungs?

Answer 48

medium-sized bronchi, even as radii decrease moving toward alveoli, the flow becomes more laminar