Factors Affecting Respiratory Function

Vocabulary terms and definitions related to the physiological, environmental, and lifestyle factors that impact respiratory health and function.

Upright posture

A standing or sitting erectly position that allows for the greatest ease of lung expansion because the diaphragm can move without abdominal organs pressing against it.

Fraction of inspired oxygen concentration (FiO2)

The percentage of oxygen in the air humans breathe, which remains stable at around $21\%$ when breathing room air.

Atmospheric pressure

Also known as barometric pressure; it decreases at higher elevations, resulting in less oxygen available to the lungs for gas diffusion.

Carbon monoxide

An emission from cars and factories that interferes with oxygenation by inhibiting oxygen attachment to hemoglobin on red blood cells.

Allergens

Substances such as pollens, dust, and foods that the body perceives as harmful, triggering an inflammatory response and the release of chemical mediators.

Allergic rhinitis

Commonly referred to as hay fever; an allergic response confined to the nose and upper airways characterized by nasal discharge, itchy eyes, and swollen mucous membranes.

Bronchospasm

A narrowing of the airways caused by inflammatory chemical mediators, which limits air exchange and is a hallmark of allergic asthma.

Mucociliary escalator

A mechanism for mucus removal in the respiratory tract that is slowed by smoking, leading to potential airway blockage and infection.

Aspiration

The accidental inhalation of stomach contents into the trachea and lungs, often occurring when alcohol depresses protective airway reflexes.

Atelectasis

A condition where the lungs or alveoli collapse, reducing the amount of space available for gas exchange; common in patients after surgery due to shallow breathing.

Restrictive lung disorders

A classification of respiratory problems where lung tissues swell and stiffen, or expansion is otherwise restricted, such as in pulmonary fibrosis or pneumonia.

Airway obstruction

Any process that reduces the diameter of the conducting airways, such as foreign material, excessive mucus, or tumors, thereby increasing airway resistance.

Airway hyperreactivity

A condition where bronchial smooth muscle becomes hyperreactive to stimuli, greatly increasing smooth muscle tone and narrowing airway lumens.

Emphysema

A condition caused by damage to bronchiole walls, making them floppy and unable to remain open during exhalation, which leads to air trapping in the alveoli.

Work of breathing

The effort required for muscle movement during respiration; in altered function, respiratory muscles may consume up to half ($1/2$) of all oxygen available to body tissues.