Respiratory system

respiratory

Abdominal cavity

A hollow space below the diaphragm and superior to the pelvic cavity that

supports major organs such as the stomach, kidneys, liver, and intestines.

Alveolus

Tiny air sacs that form clusters at the end of each bronchiole branch. Gas

exchange occurs between the alveoli and the capillaries that surround them.

Ambient air

The air in the atmosphere.

Asbestos

A carcinogen often used in construction materials. Exposure to asbestos dust is

a leading cause of lung cancer and disease.

Asthma

A condition where the bronchial tubes become inflamed and, as a result, restrict

airflow.

Atelectasis

The complete or partial collapse of the lung.

Bronchiole

The narrow airways of the lower respiratory tract that are located in the lobes

and connect the bronchi to the alveoli. They do not contain cartilage rings.

Bronchus

The larger airways in the lungs; supported by cartilage rings.

Carina

Where the esophagus opens to the A cartilage structure at the base of the

trachea that separates the openings of the main bronchi.

Cellular respiration

The process through which cells convert sugar and other nutrients to energy.

Carbon dioxide is a by-product of this process and is later released by the cells as

waste.

Chronic obstructive

pulmonary disease (COPD)

A term for chronic diseases that causes recurrent blockage of airflow in the lungs.

Cilia

Hair-like appendages present on the surface of certain cells used to sweep

substances, such as mucus, past the cell. In the nasal cavities, cilia move mucus

towards the pharynx.

COVID-19

A respiratory condition caused by a novel coronavirus called severe acute

respiratory syndrome coronavirus 2 (SARS-CoV-2).

Cricoid cartilage

A circular ring of cartilage located in the upper airway. It provides a connection

point and support for various ligaments, cartilages, and muscles, which help open

and close the vocal cords for speech production.

Diaphragm

A dome-shaped muscle that sits in the base of the lungs and separates the

thoracic and abdominal cavities.

Diffusion

The movement of a substance from a higher concentration to a lower

concentration.

Emphysema

A lung condition caused by damage to the alveoli, which eventually reduces the

amount of oxygen that reaches the bloodstream.

Epiglottis

A small, leaf-like flap of cartilage at the bottom of the laryngopharynx. The flap

closes over the larynx when a person is swallowing, preventing food or liquid

from entering the air passages.

Exhalation

The process of breathing out air. When the intercostal muscles and diaphragm

relax, lung volume decreases, and air is forced out of the lungs.

External respiration

The gas exchange between the air in the lungs and the bloodstream.

Inhalation

The process of breathing in air. It begins when the intercostal muscles and

diaphragm contract, thus expanding the thoracic cavity. This allows the lungs also

to expand and create suction which pulls air into the lungs.

Hemoglobin

A protein molecule in red blood cells responsible for carrying oxygen from the

lungs to the cells of the body and carrying carbon dioxide from the cells to the

lungs.

Intercostal muscles

Muscles between the ribs that help form and move the thoracic or chest wall.

Internal respiration

The exchange of gases between the bloodstream and the body’s cells.

Laryngopharynx

This is the lower section of the pharynx; the point where the esophagus, or the

food pipe, and the larynx, or the windpipe, branch off.

Larynx

A structure containing the vocal cords and various ligaments, cartilages, and

muscles.

Lung cancer

A cancer characterized by uncontrolled cell growth in lung tissue. It is the leading

cause of cancer deaths worldwide.

Lungs

Soft, spongy organs located in the thoracic cavity that are responsible for gas

exchange.

Mediastinum

A compartment located in the center of the thoracic cavity that separates the

lungs and contains the heart, the esophagus, and the trachea.

Mucous membrane

A layer of epithelial cells that line and protect internal body surfaces exposed to

the external environment. Mucous membranes secrete mucus, a thick, sticky

fluid that protects the body from external pathogens.

Nasal cavity

A hollow space behind the nose in the middle of the face, divided into a left and

right section by the nasal septum and lined with mucous membranes and

microscopic hairs called cilia.

Nasal hair

Hair located in the nostrils that filters out foreign materials.

Nasal Septum

Cartilage that separates the nasal cavity into a left and right sections.

Nasopharynx

The top section of the pharynx connects the pharynx to the nose. It lies behind

the nose and just above the soft palate.

Oropharynx

The middle section of the pharynx connects the pharynx to the mouth. It contains

the base of the tongue and the tonsils. The muscles of the oropharynx are

responsible for swallowing.

Oxygenation

Oxygenation is the process of supplying oxygen to the body’s tissues. Oxygen

molecules enter red blood cells, bind with hemoglobin molecules, and then travel

to the cells of the body’s tissues.

Paranasal sinuses

Eight hollow spaces, arranged in four pairs, in the skull. They open into the nasal cavity

via small passages that allow mucus to drain into the nose.

Pathogen

A microorganism, such as a virus, bacterium, or fungi that is harmful to the body and

causes illness and disease.

Peak expiratory flow rate

A measurement of airflow out of the lungs or a person’s maximum speed of expiration.

It is measured with a peak flow meter.

Peak flow meter

A meter used to measure PEFR; a small, hand-held device used to detect a person’s

ability to breathe out air.

Pharynx

This is a structure located behind the nasal cavity and mouth. It is divided into

three sections: the nasopharynx, oropharynx, and laryngopharynx.

Pleura

A thin, slippery double membrane that surrounds each lung and lines the inner

surfaces of the thoracic cavity.

Pleural fluid

A fluid that fills the space between adjacent pleural membranes to reduce

friction during the movement of breathing.

Pneumonia

An infection that causes inflammation in the alveoli in the lungs.

Pulmonary function tests

Tests that show how well the lungs are working that measure lung volume,

capacity, rates of flow, and gas exchange and help detect various diseases and

disorders of the respiratory system.

Resonance

An increase in vocal tones during speech.

Respiration

The exchange of oxygen and carbon dioxide between the atmosphere and the

body's cells occurs in two stages: external and internal respiration.

Respiratory (Pulmonary)

System

The body system responsible for breathing and the exchange of gases. The

organs of the respiratory system include the lungs and multiple air passages

where oxygen is taken in and carbon dioxide is expelled.

Spirometry

One of the most common pulmonary function tests; it measures airflow by

detecting the rate and volume of breathing.

Thoracic cavity

A hollow space surrounded by the rib cage that contains the lungs, heart, and

major blood vessels. It is separated from the abdominal cavity by the diaphragm.

Thyroid cartilage

A large piece of cartilage located in the larynx that protects the vocal cords.

Tonsils

Their main function is to trap pathogens that enter the body through the mouth

and nose, such as during respiration. Tonsils exist in three pairs: palatine,

pharyngeal [fae-RIN-gee-all] (adenoids), and the lingual tonsils.

Trachea (windpipe)

A structure that marks the beginning of the lower respiratory tract. It is the

passageway from the upper respiratory tract to the lungs.

Tuberculosis

A contagious infection that attacks the lungs and is caused by a bacteria called

Mycobacterium tuberculosis.

Ventilation

The physical act of breathing; it has two phases called inhalation and exhalation.

Vocal cords

Two bands of smooth muscle tissue that vibrate as air passes through them to

produce audio sounds.