Respiratory Compliance

How do we calculate the flow of breathing?

(atmospheric pressure - intra-alveolar pressure)/resistance

How is transpulmonary/transmural pressure calculated?

(intra-alveolar pressure) - (intrapleural pressure)

What is the value of intrapleural pressure at rest? Under what circumstances does intrapleural pressure become more negative? Less negative?

-4 mmHg at rest becomes more negative during inspiration becomes less negative during expiration

As lung compliance decreases, FRC ______ (decreases/increases). As lung compliance increases, FRC ______ (decreases/increases).

As lung compliance decreases, FRC decreases. As lung compliance increases, FRC increases.

Atmospheric pressure is _____ mm Hg at sea level, decreases as _____ increases, and increases _____. Other lung pressures are given relative to atmospheric pressure, which is why atmospheric pressure is set at _____ mm Hg.

Atmospheric pressure is 760 mm Hg at sea level, decreases as altitude increases, and increases under water. Other lung pressures are given relative to atmospheric pressure, which is why atmospheric pressure is set at 0 mm Hg.

Changing the lungs volume through inspiration, expiration, or collapse, will change the lungs ______. What formula demonstrates this relationship?

Changing the lungs volume through inspiration, expiration, or collapse, will change the lungs pressure. PV=nRT

During expiration, intra-alveolar pressure is _____ (negative/positive), and it is _____ (less/more) than atmospheric pressure.

During expiration, intra-alveolar pressure is positive, and it is more than atmospheric pressure.

During inspiration, intra-alveolar pressure is _____ (negative/positive), and it is _____ (less/more) than atmospheric pressure.

During inspiration, intra-alveolar pressure is negative, and it is less than atmospheric pressure.

_____ tissues of the lungs play a role in lung compliance.

Elastic connective tissues of the lungs play a role in lung compliance.

In emphysema, lung compliance is ______ (decreased/increased). In fibrosis, lung compliance is ______ (decreased/increased).

In emphysema, lung compliance is increased. In fibrosis, lung compliance is decreased.

Inspiration occurs when the pressure in the lungs is _____ (less/greater) than the pressure in the atmosphere. Expiration occurs when the pressure in the lungs is _____ (less/greater) than the pressure in the atmosphere.

Inspiration occurs when the pressure in the lungs is less than the pressure in the atmosphere. Expiration occurs when the pressure in the lungs is greater than the pressure in the atmosphere.

Lung compliance is inversely related to _____. As lung compliance increases, lungs become _____ to inflate and less _____ pressure is needed.

Lung compliance is inversely related to elastic recoil. As lung compliance increases, lungs become easier to inflate and less transmural pressure is needed.

Saline-filled lungs show no ______ and show higher ______. What does this indicate?

Saline-filled lungs show no hysteresis and show higher compliance. indicates that the interaction of air with the wet lung was what induced hysteresis

Small alveoli will be lined with _____ (less/more) surfactant, while large alveoli will be lined with _____ (less/more) surfactant. What does this result in?

Small alveoli will be lined with more surfactant, while large alveoli will be lined with less surfactant. results in both the small alveoli and large alveoli to remain open at the same time

The intrapleural pressure should be _____ under normal conditions and is always less than _____ pressure.

The intrapleural pressure should be negative under normal conditions and is always less than intra-alveolar pressure.

Without surfactant in the lungs, there would be unstable conditions in which _____ (small/large) alveoli would empty into _____ (small/large) alveoli and collapse.

Without surfactant in the lungs, there would be unstable conditions in which small alveoli would empty into large alveoli and collapse.

Through what mechanism does air move in and out of the lungs? What drives this process?

air moves in and out of the lungs by bulk flow pressure gradient drives bulk flow, as air moves from high to low pressure

What are the four types of pulmonary pressures?

atmospheric pressure intra-alveolar pressure intrapleural pressure transpulmonary or transmural pressure

How does the intra-pleural pressure change during inspiration? Why? During expiration?

becomes more negative during inspiration, as it is pulling the lungs open becomes more positive during expiration

How does surfactant affect the lungs? What is surfactant release stimulated by?

decreases surface tension of the fluid lining alveoli makes it easier to inflate lungs minimizes pressure differences between adjacent alveoli release stimulated by deep breath

What is surface tension due to? What is surface tension the force for in the pulmonary system?

due to attractions between water molecules surface tension is the force for alveoli to collapse or resist expansion

True or false: the transpulmonary/transmural pressure should be negative

false- it should be positive

True or false: surfactant has detergent like properties that decrease surface tension and decrease lung compliance

false- surfactant has detergent like properties that decrease surface tension and increase lung compliance

What describes the volume of air in the lungs between breaths?

functional residual capacity

What does FRC stand for and what does it represent?

functional residual capacity represents the point of the breathing cycle where the lung recoil and chest wall expansion are balanced and equal

What does an increase in transpulmonary/transmural pressure result in?

increase in distending pressure across the lungs expansion of the lungs, increasing volume

What does the transpulmonary/transmural pressure being positive indicate?

indicates that the intrapleural pressure is acting to keep the lungs pressed against the chest wall, rather than allowing them to collapse

The difference between which two pulmonary pressures drive ventilation?

intra-alveolar pressure and atmospheric pressure

What describes the pressure of air in alveoli?

intra-alveolar pressure or airway pressure

What describes the pressure within the pleural space? This pressure is generally lower than what other kind of pressure?

intrapleural pressure generally lower than atmospheric pressure

What describes the ease with which lungs can be stretched? How can this be calculated?

lung compliance change in lung volume divided by change in transpulmonary/transmural pressure

What are the two factors affecting pulmonary ventilation?

lung compliance airway resistance

What will occur to the lungs if their compliance increases due to emphysema?

lungs will be less elastic and will not collapse as much FRC will increase due to the need for more air to be inhaled to get the lungs to collapse

What will occur to the lungs if their compliance decreases due to fibrosis?

lungs will be more elastic and will collapse more FRC will decrease due to the need for less air to be inhaled to get the lungs to collapse

What will occur if the intrapleural pressure becomes 0 mmHG?

pneumothorax- collapse of the lungs

What holds the chest wall and lungs together? What way do the chest wall and lungs want to recoil in their relaxed state?

surface tension of the intrapleural fluid chest walls wants to expand outward, lungs want to recoil inward

What reduces the hysteresis caused by the interaction of air with the wet lung?

surfactant

What is hysteresis?

the difference in volume/pressure curves for inspiration and expiration

What is the negative intrapleural pressure due to?

the elasticity in the lungs and chest wall

What describes the distending pressure across the lung wall that functions to open the alveoli and airways from outside?

transpulmonary or transmural pressure