Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CRRAB II- Week 4 > Trachte: Mechanics of Breathing > Flashcards

Trachte: Mechanics of Breathing Flashcards

1
Q

How do inspiration and expiration differ?

A

Inspiration occurs by CONTRACTION of the diaphragm.

Expiration is a PASSIVE PROCESS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What innervates the diaphragm?

A

Phrenic nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If the phrenic nerve is paralyzed, why does the diaphragm move UP w/ inspiration?

A

The pressure in the thoracic cavity is lower so it gets sucked in.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is the expiration process passive?

A

Elastic recoil of the lung

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is expiration active during exercise?

A

Muscles of the abdominal wall and the internal intercostals pull the ribs downward

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When does inflation of the lung occur?

A

When pressure around the lung becomes SUBATMOSPHERIC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Does it require a greater pressure differential to inflate or deflate a lung?

A

Inflate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is hysteresis?

A

Different shapes of inflation and deflation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does the lung volume never go to 0?

A

Because some air is always trapped in the lung (Residual volume)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the airway closure pressure?

A

The pressure to exhale COLLAPSES some small airways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is compliance?

A

The relationship of volume change per pressure change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is compliance NORMALLY for the lung?

A

200 ml/cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What will reduce compliance? How does this affect your breathing?

A

Fibrotic disease

can’t expand lungs easily–> small breaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What will increase compliance? How does this affect breathing?

A

Emphysema

Slower breaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why does the lung have elasticity?

A

Collagen and elastin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is it important that the lung collapses after inspiration?

A

Reduces the work of exhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does surface tension contribute to elastic behavior?

A

Shrinks the lung

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is surface tension?

A

Attraction between adjacent molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the law of LaPlace?

A

Tension= Pressure x radius/ 2 for a sphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can the law of La Place be used to determine pressures in 2 alveoli if one has a smaller radius than the other?

A

The alveoli with a SMALLER r has to have a GREATER P. This results in the smaller alveoli emptying into the larger one.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What prevents smaller alveoli from emptying into larger ones?

A

Surfactant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does surfactant do?

A

Alters surface tension at small volumes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is surfactant?

A

dipalmitoyl phosphatidylcholine (detergent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does a detergent reduce surface tension?

A

Provides a physical BARRIER that prevents WATER MOLECULES from interacting at SMALL volumes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

When is surfactant synthesized?

A

Third trimester

26
Q

What happens if a baby is born early and it doesn’t have sufficient surfactant?

A

Respiratory distress (low compliance, atelectasis, and alveoli filled w/ transudate)

27
Q

Where is intrapleural pressure the lowest? Why?

A

BASE of the lung

The WEIGHT of the base presses against the chest wall and makes it LESS negative.

The base has a smaller RV

28
Q

What leads to the collapse of airways one exhalation?

A

Increased pressure from airways squeezing shut

29
Q

What do airways collapse on exhalation/to whom?

A

LOW lung volumes in YOUNG healthy people.

AT FRC in older folks and respiratory disease–> air trapping.

30
Q

How are the chest wall and lungs normally oriented?

A

OPPOSE each other keeping the LUNGS somewhat expanded and the the CHEST WALL somewhat compressed.

31
Q

What causes the chest wall and lung to separate?

A

Pneumothorax

32
Q

What causes the lung to collapse?

A

Elastic recoil

33
Q

When is the lung at equilibrium?

A

At LESS THAN residual volume ( minimal capacity)

34
Q

When is the chest at equilibrium?

A

At 75% of vital capacity (expanded state)

35
Q

When is the combined lung-chest curve at equilibrium?

A

At FRC

36
Q

What is the airway resistance for laminar flow?

A

P = flow x Resistance

37
Q

What happens to the cross sectional area as one progresses down the bronchial tree?

A

Increases

38
Q

What is the pressure differential during inspiration?

A

Atmospheric- alveolar (.1 cm H20)

39
Q

What are pressures in the breathing cycle in the intrapleural space?

A

-5 cm water

Decreases to -8 cm water in the intrapleural space
Increases on expiration

40
Q

What is the major site of resistance in the bronchial tree?

A

Medium sized bronchi

41
Q

Why does airway resistance DECLINE at larger volumes?

A

Negative pressure PULLS airways open

42
Q

What happens to airway resistance at SMALLER lung volumes during expiration?

A

INCREASES

43
Q

How does parasympathetic nervous stimulation affect airway resistance?

A

Increases it

44
Q

Describe how parasympathetic stimulation causes airway contraction.

A

Vagus–> Ach–> muscarinic receptors–> IP3–> Ca–> airway contraction

45
Q

Describe how sympathetic stimulation DECREASES airway resistance by causing dilation.

A 
EPI>
B2 receptors (can't be NE)>
Increases cAMP>
muscles relax>
airway dilation
46
Q

What happens to the rate of flow during expiration?

A

RAPID then FALLS

47
Q

Can one overcome the fall in expiratory flow by increased exertion?

A

NO

48
Q

What causes the drop in flow on expiration?

A

COMPRESSION of airways when the thoracic volume is DECREASED to expel air

49
Q

What happens to airway pressure as volume decreases?

A

Airway pressure DECREASES so the increased pressure in the lungs COLLAPSES these airways

50
Q

What affect does inspiration have on airways?

A

DILATES and pulls them OPEN

51
Q

What determines flow in an airway?

A

Alveolar pressure- pleural pressure

52
Q

How does emphysema affect airways?

A

Reduced recoil

Reduced radial traction (easier to compress)

53
Q

What is the forced expiratory volume (FEV1)?

A

FIRST second of expiration after maximal inhalation

54
Q

What is a normal FVC?

A

80%

55
Q

How does chronic obstructive lung disease affect FEV1 and FEV1/FVC?

A

LOWERS FEV1

LOW FEV1/FVC= 50% (hard time getting air out)

56
Q

How does restrictive lung disease (pulmonary fibrosis) affect FEV1 and FEV1/FVC?

A

LOW FEV1 and FVC

but NORMAL FEV1/FVC

57
Q

HOw is work defined?

A

Force x distance

58
Q

What is the total work of breathing?

A

Effort to overcome ELASTIC (collapsing) forces and AIRWAY RESISTANCE

59
Q

How does a stiff lung affect work?

A

Stiffer = less compliant>

more work to inflate lungs

60
Q

Why do pts w/ restrictive lung disease typically take small rapid breaths?

A

lessen work load

61
Q

Why do pts w/ chronic obstrutive disease take slow deep breaths?

A

lessen work load

CRRAB II- Week 4 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions