Mechanics of Breathing Flashcards
What is the relationship between pressure and volume
pressure and volume are inversely proportional
For air to move into the lung pressure should be _______ (below or above) atmospheric pressure
below
Air moves from a region of ______ pressure to region of ______ pressure
high to low
Lung has a tendency to _____
collapse
Chest wall has a tendency to ______
expand
Which pressure is an index of intrapleural pressure
esophageal pressure
True or false,
Intrapleural pressure is higher than alveolar and atmospheric pressure
False. it is lower than both
True or False
Gravity and posture affects pleural pressure
True
which muscle is the main muscle of inspiration
Diaphragm
Why is inspiration mostly affected when the diaphragm is paralyzed?
because the diaphragm is the main muscle of inspiration
Which muscles are the accessory muscles of inspiration
sternocleidomastoid and scalene muscles
Which muscles are the accessory muscles of expiration
abdominal (rectus abdominus etc.) & internal intercostal muscles
What organ muscle or tissue initiates inspiratory effort
brain
an increase in thoracic volume results in a ______ in intrapleural pressure
decrease
Upon inspiration, transmural pressure ____
increases
Alveoli ____ (expand or collapse) in response to increased transmural pressure
Expand
During inspiration does alveolar pressure fall below or go above atmospheric pressure
Falls below
As you inspire does tidal volume increase or decrease
Increase
As you inspire does intrapleural pressure increase or decrease
decrease
As you inspire does airflow become negative or positive
negative
As you inspire does tidal volume increase or decrease
decrease
As you inspire does transmural pressure increase or decrease
increase
Lung volume ____ (increases or decreases) with increase in transpulmonary pressure
increases
small volume increase is due to opening of ____ airways
proximal
In which condition is the lungs more compliant: emphysema or fibrosis
Emphysema
the slope of the pressure-volume curve in respiration is a measure of what
compliance
When the lungs are inflated with saline is there less or more hysteresis
Less hysteresis
Does a saline filled lungs have greater or less surface tension compared to an air filled lung
It has less surface tension
When surface tension increases does the lungs collapse or expand
it collapses
is pressure directly or indirectly proportional to radius
Indirectly proportional
Which two factors aid the stability of the alveoli
Pulmonary surfactant
Alveolar interdependence
Surfactant increase compliance or elastance
compliance
Surfact keeps alveoli dry and hence prevents_____
pulmonary edema
how can loss of surfactant lead to pulmonary edema
In the absence of surfactant there is increase in surface tension which
increases pressure in the alveoli and this
pulls water from pulmonary capillaries to alveoli
At volumes above FRC, pressure is ______
positive
At volumes below FRC, pressure is ______
negative
There is minimal lung volume when the airway pressure is ____-
zero
A _______ (negative/positive) pressure indicated the chest wall is trying to expand
negative
At what volume does the relaxation pressure become of the chest wall become 0mmHg
75% volume
there is a balance between elastic recoil and chest expansion at which point on the pressure-volume curve
at the function residual capacity at 0mmHg
Will an increased or decreased radius decrease resistance
increased radius will decrease resistance
Air flow is high when , gas density is ______ (high/low) and the tube radius _____ (large/small)
high
large
transitional flow is seen at which point in vessels
branching points
Which sized bronchi have the greatest resistance
medium size
4 factors affecting airway resistance
lung volume
tone of bronchial smooth muscle
density & viscosity of inspired gas
chemical irritants
