Resp Terms 12-19

Term

Definition

Inspiration

The process of air flowing into the lungs; diaphragm and external intercostal muscles contract.

Expiration

Air leaves the lungs; diaphragm and external intercostal muscles relax.

Diaphragm

A dome-shaped muscle that contracts during inhalation to help lungs expand.

Intercostal Muscles

Muscles between the ribs that assist in expanding and contracting the chest cavity during breathing.

Medulla & Pons

Brainstem areas that control breathing rhythm (the “pacemaker” of respiration).

Eupnea

Normal breathing rate (12–15 respirations per minute).

Hyperpnea

Deep or forceful breathing, often during exercise.

Pulmonary Ventilation

Movement of air into and out of the lungs; also known as breathing.

External Respiration

Gas exchange between the alveoli and the blood in pulmonary capillaries.

Respiratory Gas Transport

Oxygen and carbon dioxide are transported by the bloodstream to and from tissues.

Internal Respiration

Gas exchange between the blood and tissue cells.

Air-blood Barrier

The thin membrane where the alveolus and capillary meet, allowing gas exchange.

Simple Diffusion

Passive movement of gases (O₂ and CO₂) across the air-blood barrier based on concentration gradients.

Macrophages (in lungs)

Immune cells that defend the alveoli from pathogens and particles.

Lung Surfactant

Substance produced by alveolar cells to reduce surface tension and keep alveoli open.

Asthma

A respiratory disorder where airways are overly sensitive and inflamed, leading to difficulty breathing.

Chronic Bronchitis

Ongoing inflammation of respiratory mucosa that causes excessive mucus production.

Emphysema

Chronic lung condition where alveolar walls are damaged, reducing gas exchange and elasticity.

COPD

Chronic Obstructive Pulmonary Disease – a group of disorders (asthma, chronic bronchitis, emphysema) that obstruct airflow.