Brainscape's Knowledge GenomeTM

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


See full index

Physiology > chapter 7 > Flashcards

chapter 7 Flashcards

1
Q

Muscles of inspiration

A

Diaphragm
external intercostals (in pockets)
scalenes - top 2 ribs
sternomastoid - sternum

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

Muscles of expiration

A 
Rectus abdominis
Internal oblique muscles
External oblique muscles
Transversus abdominis
Internal intercostal muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

causes of increased compliance

A

normal aging lung

emphysema

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

causes of decreased compliance

A

pulmonary fibrosis
alveolar edema
collapse/atelectasis

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

what is normal compliance of human lung?

A

200 ml/cm water

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

what is specific compliance

A

compliance per unit volume of lung

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

What is Laplace’s law?

A

P = 4T/r
where P is pressure, T is surface tension, and r is radius.

When only one sur- face is involved in a liquid-lined spherical alveolus, the numerator is 2 rather than 4.

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

What is physiological advantage of surfactant?

A
  1. low surface tension on alveoli increases compliance of the lung and reduces the work of expanding it with each breath
  2. alveoli stability promoted (prevents small bubbles from collapsing while big bubbles keep getting bigger - Laplaces law)
  3. keeps alveoli dry
    - reduced surface tension of alveoli reduces the hydrostatic pressure in the tissue outside the capillaries - prevents transudation of fluid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is interdependence

A

support offered to lung units by those surrounding them

- same principle for blood vessels as the lung expands

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

regional difference in intrapleural pressure?

A

less negative at bottom psrt of lung

  • harder to blow up from RV
  • airway closure at base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the equation for the total compliance of the lung and chest wall?

A

1/CT = 1/CL + 1/CCW

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

At what TLC does the chest wall hit equilibrium?

A

75% VC

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

What is Reynolds number equation and what is the significance?

A

Re = 2rvd/n

r = radius, v = average velocity, d =density, n = viscosity

Measure of inertial forces to viscous forces

Re > 4000 = turbulent flow
Re > 2000 = transitional flow
Re < 2000 = laminar flow

Turbulent flow is more likely to occur when tube diameter high and velocity high

Fully laminar flow in small airways where Reynold number = 1

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

what is poiseuille law for laminar flow?

A

volume flow rate = P(pi)r^4/8nl

n = viscosity, l = length, pi= 3.`1415

P = K * volume flow rate

VISCOSITY OF GAS IS MORE IMPORTANT

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

What is pressure equation for turbulent flow?

A

P = K * (volume flow rate)^2

DENSITY OF GAS IS MORE IMPORTANT

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

What is airway resistance

A

Pressure difference between mouth and alveoli divided by a flow rate

17
Q

Which part of airways are chief site of resistance?

A

intermediate sized bronchi

18
Q

Why does intrapleural pressure fall during inspiration?

A
  1. Increased elastic recoil of lung

2. Reduction in alveolar pressure causes fall in intrapleural pressure

19
Q

What are factors that affect airway resistance?

A
  1. lung volume - radial traction from surrounding lung tissue
  2. contraction of bronchial smooth muscle
    - cigarette smoke
    - parasympathetic activation
    - CO2
  3. Density and viscosity of gas
    - viscosity for laminar
    - density for turbulent

Resistance = 8nl/(pi)r^4

20
Q

What is the effective driving pressure in dynamic compression?

A

alveolar minus intrapleural

Dynamic compression of the airways during a forced expiration results in flow that is effort independent. The driving pressure is then alveolar minus intrapleural pressure. In patients with chronic obstructive lung disease, dynamic compression can occur during mild exercise, thus causing severe disability.

21
Q

what are factors that worsen flow limitation?

A

airway resistance
low lung volume (reduced driving pressure)
reduced recoil pressure

22
Q

What is transpulmonary pressure?

A

Pressure difference between inside and outside of lung

When alveolar pressure is atmospheric, it is numerically equal to the pressure around the lung

23
Q

What happens to compliance during an asthma attack?

A

Increases (mechanism not known)

24
Q

What is pulmonary resistance?

A

Airway and tissue resistance

20% of total resistance in normal subjects

25
Q

What is work of breathing on inspiration made up of?

A
  1. Elastic forces
  2. Viscous forces (airway and tissues) resistance
  • on expiration, the work is less because of the energy stored in the expanded elastic structures
26
Q

What is the equation for efficiency of work of breathing? (O2 cost of breathing)

What is normal efficiency at rest?

A

efficiency % = useful work / total energy expended (or O2 cost) x 100

Efficiency at rest is 5-10%

Physiology (10 decks)

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