Respiratory System Terminology

Respiratory system

The organs and structures involved in breathing and gas exchange.

Upper respiratory tract

The nose, nasal cavity, sinuses, and pharynx.

Lower respiratory tract

The larynx, trachea, bronchi, bronchioles, and lungs.

Nasopharynx

The upper portion of the pharynx located behind the nose.

Oropharynx

The middle portion of the pharynx located behind the mouth.

Laryngopharynx

The lower portion of the pharynx that connects toward the larynx and esophagus.

Larynx

The voice box; connects the pharynx to the trachea.

Epiglottis

A flap that helps prevent food from entering the airway during swallowing.

Glottis

The opening between the vocal folds.

Trachea

The windpipe connecting the larynx to the bronchi.

Bronchus

One of the major air passages branching from the trachea.

Bronchiole

A small airway branch within the lungs.

Alveolus

A tiny air sac where oxygen and carbon dioxide are exchanged.

Surfactant

A substance produced in the lungs that reduces surface tension and helps keep alveoli open.

Diaphragm

The main muscle of breathing located beneath the lungs.

Inspiration

Breathing air into the lungs.

Expiration

Breathing air out of the lungs.

Ventilation

Movement of air into and out of the lungs.

External respiration

Gas exchange between alveoli and pulmonary blood.

Internal respiration

Gas exchange between systemic blood and body tissues.

Hypoxia

Insufficient oxygen reaching body tissues.

Hypoxemia

Abnormally low oxygen level in the blood.

Cyanosis

Bluish discoloration caused by inadequate oxygenation of blood.

Asthma

A chronic inflammatory airway disorder causing episodes of narrowed airways and difficulty breathing.

Chronic obstructive pulmonary disease (COPD)

A group of diseases causing persistent airflow limitation, especially emphysema and chronic bronchitis.

Emphysema

A lung disease involving destruction of alveolar walls and reduced gas exchange.

Chronic bronchitis

Long-term inflammation of the bronchi with chronic mucus-producing cough.

Pneumonia

An infection causing inflammation and fluid/inflammatory material in the lung air sacs.

Tuberculosis (TB)

A bacterial infection, usually affecting the lungs, caused by Mycobacterium tuberculosis.

Pleurisy

Inflammation of the pleura surrounding the lungs.

Pleural effusion

Abnormal accumulation of fluid in the pleural space.

Pneumothorax

Collapse of a lung caused by air entering the pleural space.

Pulmonary edema

Abnormal accumulation of fluid in the lungs.

Pulmonary fibrosis

Scarring of lung tissue that makes breathing and gas exchange difficult.

Sleep apnea

Repeated interruptions of breathing during sleep.

Laryngitis

Inflammation of the larynx.

Pharyngitis

Inflammation of the pharynx.

Bronchitis

Inflammation of the bronchi.

Respiratory failure

A condition in which the respiratory system cannot adequately oxygenate blood or remove carbon dioxide.

Spirometry

A pulmonary function test measuring airflow and lung volumes.