Respiratory tract

Jump to navigation Jump to search

WikiDoc Resources for Respiratory tract


Most recent articles on Respiratory tract

Most cited articles on Respiratory tract

Review articles on Respiratory tract

Articles on Respiratory tract in N Eng J Med, Lancet, BMJ


Powerpoint slides on Respiratory tract

Images of Respiratory tract

Photos of Respiratory tract

Podcasts & MP3s on Respiratory tract

Videos on Respiratory tract

Evidence Based Medicine

Cochrane Collaboration on Respiratory tract

Bandolier on Respiratory tract

TRIP on Respiratory tract

Clinical Trials

Ongoing Trials on Respiratory tract at Clinical

Trial results on Respiratory tract

Clinical Trials on Respiratory tract at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Respiratory tract

NICE Guidance on Respiratory tract


FDA on Respiratory tract

CDC on Respiratory tract


Books on Respiratory tract


Respiratory tract in the news

Be alerted to news on Respiratory tract

News trends on Respiratory tract


Blogs on Respiratory tract


Definitions of Respiratory tract

Patient Resources / Community

Patient resources on Respiratory tract

Discussion groups on Respiratory tract

Patient Handouts on Respiratory tract

Directions to Hospitals Treating Respiratory tract

Risk calculators and risk factors for Respiratory tract

Healthcare Provider Resources

Symptoms of Respiratory tract

Causes & Risk Factors for Respiratory tract

Diagnostic studies for Respiratory tract

Treatment of Respiratory tract

Continuing Medical Education (CME)

CME Programs on Respiratory tract


Respiratory tract en Espanol

Respiratory tract en Francais


Respiratory tract in the Marketplace

Patents on Respiratory tract

Experimental / Informatics

List of terms related to Respiratory tract

In humans the respiratory tract is the part of the anatomy that has to do with the process of respiration.

The respiratory tract is divided into 3 segments:

The respiratory tract is a common site for infections. Upper respiratory tract infections are probably the most common infections in the world.

Most of the respiratory tract exists merely as a piping system for air to travel in the lungs; alveoli are the only part of the lung that exchanges oxygen and carbon dioxide with the blood.

Moving down the respiratory tract starting at the trachea, the tubes get smaller and divide more and more. There are estimated to be about 20 to 23 divisions, ending up at an alveolus.

Even though the cross-sectional area of each bronchus or bronchiole is smaller, because there are so many, the total surface area is larger. This means there is less resistance at the terminal bronchioles. (Most resistance is around the 3-4 division from the trachea due to turbulence.)

General histology

The respiratory tract is covered in an epithelium, the type of which varies down the tract. There are glands and mucus produced by goblet cells in parts, as well as smooth muscle, elastin or cartilage.

Most of the epithelium (from the nose to the bronchi) is covered in pseudostratified columnar ciliated epithelial cells, commonly called respiratory epithelium. The cilia beat in one direction, moving mucus towards the throat where it is swallowed. Moving down the bronchioles, the cells get more cuboidal in shape but are still ciliated.

Cartilage is present until the small bronchi. In the trachea they are C-shaped rings, whereas in the bronchi they are interspersed plates.

Glands are abundant in the upper respiratory tract, but there are fewer lower down and they are absent from the bronchioles onwards. The same goes for goblet cells, although there are scattered ones in the first bronchioles.

Smooth muscle starts in the trachea, where it joins the C-shaped rings of cartilage. It continues down the brochi and bronchioles which it completely encircles.

Instead of hard cartilage, the bronchi and brochioles have a lot of elastic tissue.


  • Syllabus: Infectious Diseases see Respiratory Tract Infections by Neal Chamberlain, PhD. Kirksville College of Osteopathic Medicine, Missouri, USA

See also

de:Atemtrakt la:Apparatus respiratorius

Template:WH Template:WS