21 - Chapter 12: Vocabulary

adenoids

Lymphatic tissue in the nasopharynx; pharyngeal tonsils.

alveolus (plural: alveoli)

Air sac in the lung.

apex of the lung

Tip or uppermost portion of the lung. An apex is the tip of a structure. Apical means pertaining to or located at the apex.

base of the lung

Lower portion of the lung; from the Greek basis, foundation. Basilar means located at or in the base.

bronchioles

Smallest branches of the bronchi. Terminal bronchioles lead to alveolar ducts.

bronchus (plural: bronchi)

Branch of the trachea (windpipe) that is a passageway into the lung; bronchial tube.

carbon dioxide (CO₂)

Gas produced by body cells when oxygen and carbon atoms from food combine; exhaled through the lungs.

cilia

Thin hairs attached to the mucous membrane epithelium lining the respiratory tract. They clear bacteria and foreign substances from the lung. Cigarette smoke impairs the function of cilia.

diaphragm

Muscle separating the chest and abdomen. It contracts to pull air into the lungs and relaxes to push air out.

epiglottis

Lid-like piece of cartilage that covers the larynx, preventing food from entering the larynx and trachea during swallowing.

exhalation

Breathing out; expiration.

glottis

Slit-like opening to the larynx.

hilum of the lung

Midline region where the bronchi, blood vessels, and nerves enter and exit the lungs. Hilar means pertaining to (at) the hilum.

inhalation

Breathing in; inspiration.

larynx

Voice box; containing the vocal cords.

lobe

Division of a lung.

mediastinum

Region between the lungs in the chest cavity. It contains the trachea, heart, lymph nodes, major blood vessels, esophagus, and bronchial tubes.

nares

Openings through the nose carrying air into the nasal cavities; nostrils.

oxygen (O₂)

Gas that makes up 21 percent of the air that we breathe. It passes into the bloodstream at the lungs and travels to all body cells.

palatine tonsil

One of a pair of almond-shaped masses of lymphatic tissue in the oropharynx (palatine means pertaining to the roof of the mouth).

paranasal sinus

One of the air cavities in the bones near the nose.

parietal pleura

Outer layer of pleura lying closer to the ribs and chest wall.

pharynx

Throat; including the nasopharynx, oropharynx, and laryngopharynx.

pleura

Double-layered membrane surrounding each lung.

pleural cavity

Space between the layers of the pleura.

pulmonary parenchyma

Essential parts of the lung, responsible for respiration; bronchioles and alveoli.

respiration

Exchange of gases (oxygen and carbon dioxide) at the lung capillaries (external respiration or breathing) and at the tissue capillaries (internal respiration).

trachea

Windpipe.

visceral pleura

Inner layer of pleura lying closer to the lung tissue.