Chapter 23, Lecture 3

Fill-in-the-blank flashcards covering intrapleural pressure, Boyle’s law, inhalation/exhalation pressure changes, pneumothorax, surfactant, lung compliance, airway resistance, and related physiology.

The pressure within the pleural cavity is always __ relative to atmospheric pressure.

negative (lower than 760 mm Hg)

A thin layer of __ in the pleural cavity creates surface tension that helps generate negative intrapleural pressure.

serous fluid

The pleura adheres to the chest wall, while the pleura adheres to the lung surface.

parietal; visceral

Just before quiet inhalation, both atmospheric pressure and alveolar pressure equal __ mm Hg.

760

During quiet inhalation, alveolar pressure drops to about __ mm Hg, drawing air in.

758

According to __ Law, when the volume of a closed container increases, the pressure inside decreases.

Boyle’s

During quiet exhalation, alveolar pressure rises to roughly __ mm Hg, pushing air out.

762

Air always flows from regions of pressure to regions of pressure.

higher; lower

Negative intrapleural pressure keeps the lungs and chest wall moving together; loss of this pressure causes the lung to __.

collapse

A __ is the presence of air in the pleural cavity that eliminates negative intrapleural pressure.

pneumothorax

Surface tension of alveolar fluid tends to make alveoli __ unless counteracted.

collapse (shrink)

The oily substance that reduces alveolar surface tension is called __.

surfactant

Respiratory distress syndrome in premature infants is mainly due to insufficient __ production.

surfactant

Lung __ refers to the ease with which the lungs and chest wall can expand.

compliance

Pulmonary fibrosis, edema, or surfactant deficiency will __ (raise/lower) lung compliance.

lower

Airflow is proportional to the pressure gradient and inversely proportional to airway __.

resistance

Bronchoconstriction airway resistance and airflow.

increases; decreases

Parasympathetic stimulation typically causes __ of the bronchioles.

bronchoconstriction

Sympathetic stimulation or epinephrine causes __ of the bronchioles.

bronchodilation

Patients with COPD may expend up to about __ % of their energy just on breathing.

25

Forced inhalation recruits the and muscles in addition to the diaphragm and external intercostals.

scalenes; sternocleidomastoid

Surfactant is secreted by alveolar __ (cell type) cells.

type II

Negative intrapleural pressure is roughly __ mm Hg less than atmospheric pressure at rest.

4