AMA 179 - Anatomy &
Physiology/Medical
Terminology/Pathology 10
Respiratory System
Function:
Mechanical process of breathing, or exchange of air
between the lungs and the external environment, and
the exchange of gases at the cellular level


External respiration: oxygen is inhaled into the lungs
and passed into blood vessels (capillaries), carbon
dioxide passes from cells into capillaries and is
exhaled
Internal respiration: exchange of gases in all body
cells, oxygen is released into cells from the capillaries
and carbon dioxide is sent from the cells into the
capillaries
Structure of the Respiratory System:

Nose: air enters body here

Nasal cavity: filters foreign bodies; warms and moistens air

Paranasal sinuses: air-containing spaces in the skull; produce mucus to lubricate and help
produce sound

Pharynx: throat

Nasopharynx: division of the throat that contains adenoids

Adenoids: collections of lymphatic tissue

Oropharynx: division of the throat that contains tonsils

Palatine tonsils: rounded masses of lymphatic tissue

Laryngopharynx: serves as a common passage for food from the mouth and air from the
nose; divides into two passages

Larynx: voice box

Esophagus: leads to the stomach, carries food to be digested

Epiglottis: flap of cartilage on root of the tongue that prevents choking or aspiration of
food; acts as a lid to cover the larynx when swallowing
Structure of the Respiratory System
Continued:

Trachea: windpipe, tube connecting larynx to the bronchial tubes

Bronchial tubes: branches of the trachea that lead to each lung

Bronchi: smaller branches of the bronchial tubes; branches out to smaller and smaller tubes
like the branches of a tree.

Lungs: two sack-like breathing organs in thoracic cavity; right has 3 lobes, left has 2 lobes

Bronchioles: smaller branches of the bronchi that narrow into alveolar ducts

Alveoli: collections of air sacs at the end of the terminal bronchiole

Capillary: smallest blood vessel; surrounds alveoli where exchange of gases occurs

Erythrocytes: red blood cells that carry oxygen to all parts of the body and carbon dioxide
to the lungs for exhalation

Parietal pleura: outer membrane covering lungs

Visceral pleura: inner membrane covering lungs

Diaphragm: muscular partition that separates the thoracic from the abdominal cavity; aids
in breathing by contracting and relaxing, helping air to enter and leave the lungs