Brainscape's Knowledge GenomeTM

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


See full index

Physiology Hilary > 2. Lung mechanics > Flashcards

2. Lung mechanics Flashcards

1
Q

What are the three different pressure concentrations important in ventilation?

A
  • Atmospheric (barometric) pressure
  • Intra-alveolar pressure (intrapulmonary pressure)
  • Intrapleural pressure (intrathoracic pressure)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Atmospheric pressure at sea level

A

760 mm Hg

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

What happens to atmospheric pressure as altitude increases?

A

It decreases

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

What is intra-alveolar pressure?

A

The pressure of air in alveoli (open system)

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

Intra-alveolar pressure during inspiration/expiration

A

–During inspiration = negative (less than atmospheric)

–During expiration = positive (more than atmospheric)

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

What drives ventilation?

A

Difference between Palv and Patm drives ventilation

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

What is intrapleural pressure?

A

The pressure inside the pleural sac (closed system)

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

Intrapleural pressure at rest

A

756 (or -4) mm Hg

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

What is lower alveolar or intra-alveolar or intra-pleural pressure?

A

Intrapleural is always lower

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

Under normal conditions at rest, is intrapleural pressure always positive or negative?

A

Always negative

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

Why is there negative intrapleural pressure at rest?

A

Elasticity in lungs and chest wall

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

Structures working to create negative intrapleural pressure

A

– Lungs recoil inward
– Chest wall recoils outward
– Opposing pulls on intrapleural space
– Surface tension of intrapleural fluid hold wall and lungs together (H2O molecules are polar, attract each other)
– Sub-atmospheric P: due to vacuum in the pleural cavity

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

FRC

A

Functional Residual Capacity

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

Functional Residual Capacity (FRC)

A

Volume of air in lungs between breaths (defined as rest);

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

Transmural pressure gradient across lung wall =

A

Intra-alveolar pressure minus intrapleural pressure.

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

Transmural pressure gradient across thoracic wall =

A

Atmospheric pressure minus intrapleural pressure

17
Q

Pneumothorax meaning

A

Punctured lung

18
Q

Diagram traumatic pneumothorax

A
19
Q

Diagram spontaneous pneumothorax

A
20
Q

Air flow =

A
21
Q

Mechanics of breathing

A

• Atmospheric pressure constant (during breathing cycle)
• Therefore, changes in alveolar pressure create/change gradients
• Boyle’s Law: pressure is inversely related to volume in an airtight container (closed system)
• Thus – can change alveolar pressure by changing its volume
• R = resistance to air flow
– Resistance related to radius of airways and mucus

22
Q

Factors determining intra-alveolar pressure

A
  • Quantity of air in alveoli

- Volume of alveol

23
Q

Inspiration

A
  • Lungs expand – alveolar volume increases
  • Palv decreases
  • Pressure gradient: air into lungs
  • Quantity of air in alveoli rises
  • Palv increases
24
Q

Expiration

A
  • Lungs recoil – alveolar volume decreases
  • Palv increases
  • Pressure gradient: air out of lungs
  • Quantity of air in alveoli decreases
  • Palv decreases
25
Q

Breathing cycle pressures diagram

A
26
Q

Respiratory Muscle Activity During Inspiration

A
  • Contraction of diaphragm
  • Contraction of external intercostal muscles
  • Elevated rib cage
27
Q

Respiratory Muscle Activity During Expiration

A
  • Contraction of internal intercostal muscles

- Contraction of abdominal muscles

28
Q

Forced expiration5

A
29
Q

Flow-Volume Loop

A
30
Q

Factors Affecting Pulmonary Ventilation

A
  • Lung Compliance

* Airway Resistance

31
Q

Lung Compliance

A

Ease with which lungs can be stretched

32
Q

What is lung compliance affected by

A
  • By elasticity (elastic recoil) and surface tension of lungs (alveoli) (type II cells produce surfactant to decrease surface tension)
33
Q

The less compliant the lungs are…

A

The more work is required to produce a given degree of inflation

34
Q

What is airway resistance affected by?

A

Passive forces, contractile activity of smooth muscle and mucus secretion

35
Q

When is airway resistance increased?

A

In pathologies

36
Q

How much total energy expenditure does quiet breathing require

A

3%

37
Q

When is work of breathing increased ? x 5

A
  • When pulmonary compliance is decreased
  • When airway resistance is increased
  • When elastic recoil is decreased
  • When there is a need for increased ventilation
  • For instance, COPD: 30% EE at rest
38
Q

Spirograph

A

Physiology Hilary (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions