Week 9 Flashcards

1
Q

Conducting Zone

A

Anatomical Dead Space
- No gas exchange
- Reinforced with cartilage
- Smooth Muscle regulates diameter

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

Respiratory Zone

A
  • Gas Exchange
  • little cartilage or smooth muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Regions in the conducting zone

A

Larynx, Trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles and terminal bronchioles

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

Regions in the respiratory zone

A

Respiratory bronchioles, alveolar sacs

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

tidal volume

A

Volume of single breath

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

Vital Capacity

A

Limit for inhalation/exhalation

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

Residual Volume

A

Conducting zone (about 150 mL) plus minimum volume in alveoli (1L)

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

Total lung capacity

A

Vital Capacity + residual volume

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

Functional Residual Capacity

A

Volume of conducting zone and alveoli after normal exhalation

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

How is the fresh air that enters the lungs with each breath determined

A

tidal volume - dead space volume = about 350 mL at rest

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

How does functional residual capacity impact the PO2 and PCO2 relative to the outside air

A
  • FRC (about 2000mL at rest) is old air that already underwent gas exchange
  • only small fraction of alveolar air is being replaced with each breath because FRC&raquo_space; Vt-Vd
  • Causes lower O2 pressure and higher CO2 pressure compared to outside
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Calculating total ventillation

A

Total volume of air flow into the lungs and airways per minute
= tidal volume x breathing frequency
In humans, about 6L/min = 500 mL x 12 / minutes

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

Calculating Alveolar Ventilation

A

Total air flow into the alveoli per minute (anatomical dead space doesn’t participate in gas exchange)
= (Vt-Vd) x fR
In humans, 4.2 L/min = (500mL-150mL) x 12/min

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

How does alveolar ventilation determine gas exchange

A
  • Determines alveolar partial pressures, and thus diffusion rates
  • Increasing AV increases the rate at which fresh air enters the FRC in alveoli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Does tidal volume or breathing frequency lead to a greater improvement in gas exchange

A

Increasing tidal volume produces a greater increase in gas exchange

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

What muscles are involved in breathing

A

Diaphragm, intercostal and abdominal muscles

17
Q

What muscles are involved in inspiration

A
  • Diaphragm contracts, expanding the thoracic cavity downwards
  • External intercostal rotate ribs outward and upward
18
Q

What muscles are involved in expiration

A
  • Passive respiration relies on recoil force
  • Active expiration involves the internal intercostals contracting, rotating the ribs in and downward, abdominals push organs against diaphragm to compress thoracic cavity upward
19
Q

Pleural sac

A
  • Pleural membranes encase the lungs and lines the inside of the thoracic cavity
  • The intrapleural space is fully enclosed and fluid filled, creating a flexible lubricated connection between the lungs and chest wall, held together by negative pressure
  • connection between thorax and lungs ensuring lungs follow size changes
20
Q

What creates the negative force in the intrapleural space

A

the opposing elastic recoil forces of the lungs and the chest walls

21
Q

Def: elasticity

A

The tendency of a structure to resume its normal shape after being stretched

22
Q

Why are there opposing recoil forces between the chest wall and lungs

A
  • Pleura holds structures together
  • The lungs are larger than they would normally be
  • Chest wall is smaller than normal
  • causes recoil forces proportional to the magnitude of stretch applied to these structures
  • Fluid in intrapleural space prevents recoiling (hard to compress/expand)
23
Q

Pneumothroax

A

Conditions in which air accumulates within the intrapleural space

24
Q

how will pneumothorax affect intrapleural pressure, lung volume, ventilation and the chest wall?

A
  • Intrapleural pressure = 0 relative to atmosphere
  • Decrease in lung volume
  • Increase in chest wall
  • Intrapleural space increase in size
  • Ventilation would stop - no mechanism to increase lung volume
25
Q

When does inhalation stop based on force vectors

A
  • Force of muscle causes expansion
  • As expansion occurs, force of lung recoil increases and force of chest recoil decreases
  • When the force of muscle + the chest recoil force = lung recoil force, inhalation will stop
26
Q

Transpulmonary pressure

A

The transpulmonary pressure difference (Palv- Pip) is the force that expands the lungs above its resting volume, opposing the recoil force

27
Q

What pressures drive airflow in/out of the lungs

A

The pressure difference between the atmosphere and alveoli
Airflow= (Patm-Palv)/flow resistance

28
Q

What are the changes in pressure and volume throughout inhalation

A
  • Increase force to expand chest
  • Decrease in intrapleural pressure
  • Increase in the transpulmonary pressure
  • increase force to expand lungs
  • Decrease in alveolar pressure
  • inhalation
  • Increase in lung volume
29
Q

What are the changes in pressure and volume throughout exhalation

A
  • Decrease force to expand chest
  • Increase in intrapleural pressure
  • Decrease in transpulmonary pressure
  • Increase in alveolar pressure
  • exhalation
  • decrease in lung volume
30
Q

How will increase in airway resistance affect breath volume over time

A

Increase in resistance causes a decrease in flow

31
Q

What determines the compliance of the lungs

A

The elastic forces that lead to recoil
1. Lung tissue: primarily due to elastin and collagen
2. Surface tension of fluid lining lungs

32
Q

What determines compliance of the lungs

A

the change in lung volume as a result of changes in pleural pressure

33
Q

Surface tension

A

The cohesion of liquid molecules at air interface
- Tends to reduce lung volume, so increasing lung volume requires transpulmonary pressures that overcome inward force due to surface tension

34
Q

Surfactant

A
  • Secreted by alveolar type II cells
  • a detergent-like mix of phospholipids and proteins that reduces surface tension
  • more concentrated in smaller alveoli, further reducing surface tension and preventing collapse (P=2T/r - greater surface tension due to smaller radius)
35
Q

Lymphatic System and Intrapleural Pressure

A

The lymphatic pump creates a negative pressure within lymph vessels that sucks fluid out of the intrapleural space and reduces intrapleural pressure