alveoli — microscopic air sacs in the lungs where gas exchange occurs with the circulatory system
anoxia — absence of oxygen in the circulating blood or in the tissues
aorta — the largest vessel of the systemic arterial system, from which the main arteries carrying oxygenated blood branch out and subdivide into smaller and smaller vessels
arterial gas embolism (AGE) — gas bubbles in the arterial system generally caused by air passing through the walls of the alveoli into the bloodstream
arteriole — small artery
atelectasis — the collapse of all or part of a lung
atrium — chamber of the heart that provides access to another chamber called the
ventricle
bronchi — plural of bronchus, which is a division of the trachea
bronchiole — small branch of the bronchus that carries air to and from the alveoli
bronchospasm — bronchoconstriction, or the sudden narrowing of the smaller airways, of a spasmodic nature
capillary — microscopic blood vessels where the gas exchange takes place between the bloodstream and the tissues or the air in the lungs
carbon dioxide — a waste gas produced by the metabolism of oxygen in the body
carbon monoxide — a highly poisonous, odorless, tasteless and colorless gas formed when carbon material burns with restricted access to oxygen. It is toxic by inhalation since it competes with oxygen in binding with the hemoglobin, thereby resulting in diminished availability of oxygen in tissues.
cartilaginous — pertaining to or composed of cartilage
cilia — long, slender microscopic hairs extending from cells and capable of rhythmic motion
CPR — cardiopulmonary resuscitation
decompression illness (DCI) — dysbaric injuries related to scuba diving; DCI includes both decompression sickness (DCS) and arterial gas embolism (AGE).
decompression sickness (DCS) — a syndrome caused by bubbles of inert gas forming in the tissues and bloodstream that can evolve from ascending too rapidly from compressed gas diving
dehydration — an abnormal depletion of water and other body fluids
Diameter Index Safety System (DISS) — intermediate pressure port where a hose attaches, leading to demand valve or other apparatus
EMS — emergency medical services
epiglottis — thin structure behind the tongue that shields the entrance of the larynx during swallowing, preventing the aspiration of debris into the trachea and lungs
erythropoietin — a hormone that is synthesized mainly in the kidneys and stimulates red blood cell formation
esophagus — portion of the digestive tract that lies between the back of the throat and stomach
fossa ovalis — oval depression in the wall of the heart remaining when the foramen ovale closes at birth (See patent foramen ovale.)
gradient — the difference in pressure, oxygen tension or other variable as a function of distance, time or other continuously changing influence
hypoxemia — inadequate oxygen content in the arterial blood
hypoxia — inadequate oxygen content
incontinence — absence of voluntary control of an excretory function, especially defecation or urination
inert — having little or no tendency to react chemically
intercostal muscles — the muscles between the ribs that contract during inspiration to increase the volume of the chest cavity
ischemia — inadequate blood flow to a part or organ
larynx — the organ of voice production, also known as the voice box; the opening from the back of the throat into the trachea (windpipe)
lpm — liters per minute; a measurement of a flow rate of gas or liquid
mediastinum — the space within the chest located between the lungs, containing the heart, major blood vessels, trachea and esophagus
metabolism — the conversion of food into energy and waste products
nystagmus — spontaneous, rapid, rhythmic movement of the eyes occurring on fixation or on ocular movement
oblique — an indirect or evasive angle
occlude — to close off or stop up; obstruct
oxygen — a colorless, odorless, tasteless gas essential to life, making up approximately 21 percent of air
patent foramen ovale — a hole in the septum (wall) between the right and left atria of the heart
pericardium — a double-layered membranous sac surrounding the heart and major blood vessels connected to it
pharynx — portion of the airway at the back of the throat, connecting mouth, nasal cavity and larynx
platelet — a round or oval disk found in the blood of vertebrate animals that is involved with blood clotting
pleura — membranes surrounding the outer surface of the lungs and the inner surface of the chest wall and the diaphragm
prescription — a written order for dispensing drugs signed by a physician
primary assessment — assessment of the airway, breathing and circulation (pulse) in an ill or injured person; also known as the ABCs
psi — pounds per square inch; a measurement of pressure
respiratory arrest — cessation of breathing
sign — any medical or trauma condition that can be observed
supine — lying face up
surfactant — a substance produced in the lungs to reduce surface tension in alveoli and small airways
symptom — any nonobservable condition described by the patient
thorax — the upper part of the trunk (main part of the body) between the neck and the abdomen that contains the heart, lungs, trachea and bronchi
trachea — the air passage that begins at the larynx and ends as the beginning of the principal right and left bronchi
Valsalva maneuver — the forced inflation of the middle ear by exhaling with the mouth closed and the nostrils pinched
venous gas emboli — inert gas bubbles in venous blood (that return to the heart and lungs)
ventilation — the exchange of gases between a living organism and its environment; the act of breathing
ventricle — thick-walled, muscular chamber in the heart that receives blood from the atrium, pumping it through to the pulmonary or systemic circulation
venules — small veins