RES 2

These flashcards cover key concepts related to the respiratory system, including lung volumes, capacities, ventilation, surfactant function, and related physiological principles.

Tidal volume (VT)

Volume of air inspired or expired during a normal and quiet respiratory cycle (≈ 500 ml).

Inspiratory reserve volume (IRV)

Volume of air that can be inspired forcefully after a normal quiet inspiration (≈ 3,000 ml).

Expiratory reserve volume (ERV)

Volume of air that can be expired forcefully after a normal quiet expiration (≈ 1,100 ml).

Residual volume (RV)

Volume of air remaining in the respiratory passages and lungs after forceful expiration (≈ 1,200 ml).

Total lung capacity (TLC)

Sum of inspiratory and expiratory reserve volumes plus tidal volume and residual volume (≈ 5,800 ml).

Inspiratory capacity (IC)

Inspiratory reserve volume plus tidal volume (≈ 3,500 ml).

Functional residual capacity (FRC)

Volume of air remaining in the respiratory passages and lungs after a normal quiet expiration (≈ 2,300 ml).

Vital capacity (VC)

Volume of air that can be forcefully expired after maximum forceful inspiration (≈ 4,600 ml).

Anatomical dead space

Area within the conducting zone where gas exchange does not take place (≈ 150 ml).

Physiological dead space

Anatomical dead space plus the volume of any alveoli where gas exchange is less than normal.

Surfactant

A mixture of proteins and lipids secreted by type II alveolar cells that reduces surface tension in the lungs.

Compliance

The ease with which the lungs can expand; higher compliance means less pressure is required to inflate the lungs.

Laplace's Law

Describes the relationship between surface tension, radius, and pressure within a bubble: p = 2T/r.

Pulmonary fibrosis

A condition that decreases lung compliance due to prolonged exposure to harmful substances.

Ventilation rate

The frequency of breaths taken per minute, typically ≈ 12 to 15 breaths/min.

Minute ventilation

The volume of air ventilated per minute, calculated as tidal volume multiplied by ventilation rate.

Alveolar ventilation (VA)

The volume of air available for gas exchange per minute.