Bma Illustrated Medical Dictionary

inflammation of surrounding tissues, or

pressure, for example from an impacted

tooth. Internal resorption is rare, occur-

ring in about 1 percent of adults.

respirationA term for the processes by

which oxygenreaches body cells and is

utilized by them, and by which carbon

dioxideis eliminated. Air, containing

oxygen, is breathed into the lungsand

enters thealveoli. Oxygen diffuses into

the blood, which carries it to cells in the

body, where it is used to metabolize

glucose to provide energy. Carbon diox-

ide is produced as a waste product and

passes into the blood from the body

cells. It is transported to the lungs to be

breathed out (see respiratory system).

respiratorSee ventilator.

respiratory arrestSudden cessation of

breathing,resulting from any process

that severely depresses the function of

the respiratory centre in the brain. Causes

include prolonged seizures, an overdose

of opioid drugs, cardiac arrest, electrical

injury, serious head injury, stroke, or res-

piratory failure. Respiratory arrest leads

to anoxia and, if untreated, cardiac arrest,

brain damage, coma, and death.

respiratory distress syndromeAn

acute lung disorder that makes breathing

difficult, resulting in a life-threatening

deficiency of oxygenin the blood. There

are 2 types of the syndrome. In prema-

ture babies, the lungs are stiff and do

not inflate easily due to a lack of surfac-

tant. In adults, it develops as a result of a

severe injury or overwhelming infection.

Treatment is for the underlying cause,

and is with artificial ventilationand oxy-

gen; inhaled surfactant is given to babies.

respiratory failureA condition in which

there is a buildup of carbon dioxideand

a fall in the level of oxygen in the blood

(see hypoxia). Causes include lung disor-

ders, such as severe asthma,emphysema,

or chronic bronchitis (seepulmonary dis-

ease, chronic obstructive), or damage to

the respiratory centre in the brain due

to, for example, an overdose of opioid

drugs,a stroke, or serious head injury.

Treatment is with ventilationand oxy-

gen for the underlying cause.

respiratory function testsSee pul-

monary function tests.

respiratory systemThe organs respon-

sible for carrying oxygenfrom the air to

the blood and expelling

carbon dioxide.

The upper part of the

respiratory system con-

sists of 2 nasal passages;

the pharynx; the larynx

(which contains the

vocal cords); and the

trachea. The lower part

of the respiratory tract

consists of two lungs,

which are enclosed in a

double membrane called

the pleura, and the lower

airways (the bronchiand

smaller bronchioles).

These structures are

encased and protected

by the bony ribcage. The

airways terminate in

millions of balloon-like

sacs known as alveoli,

where gas exchange

with the tiny blood ves-

sels surrounding them

takes place. These small

vessels feed into larger

RESPIRATION RESPIRATORY SYSTEM

R

RESPIRATORY SYSTEM

Diaphragm

Intercostal

muscle

Heart

Larynx

Lung

Vocal cords

Pharynx

Nasal cavity Adenoids

Nostril

Tonsil

Epiglottis

Trachea

Bronchus

Pulmonary vessel

Pleura

Rib