Difference Between Bronchi and Bronchioles

Main Difference

The difference between bronchi and bronchioles is that the bronchi are air passages into the lungs that begin at the end of the trachea. While the bronchioles or bronchioli are the passageways by which air passes through the nose or mouth to the alveoli of the lungs, in which branches no longer contain cartilage or glands in their sub-mucosa.

Bronchi vs. Bronchioles

The 24-hrs long respiratory system is one of the most crucial systems in a living body, the tubes starting from the throat, larynx to the trachea and other plays pivotal role in conducting this process. Bronchi (plural of Bronchus) and Bronchioles are also the two of tubes; the latter is a smaller tube that extends from each bronchus (plural: bronchi) to Alveoli, which is the sac-like structure found at the end of long series of tubes. On the other hand, Bronchus (Bronchi), extends off from the trachea into each lung, and later gets divided into multiple tubes, which later connects to a network of smaller tubes called Bronchioles. There are two Bronchus that branch off from the trachea into each lung, whereas hundreds of Bronchioles in each lung (smaller tubes) make their way to Alveoli.

Comparison Chart

BronchiBronchioles
DiameterMoreLess
TransportBronchi transport air to bronchioles.Bronchioles flow air into alveoli.
Consists up ofCartilaginous LayerSmooth muscles and elastic tissues lined with epithelium.

What is Bronchi?

Bronchi are the pair of respiratory tracts that extends air from the Trachea and later pass it on to the multiple smaller tubes (Bronchioles). There is two Bronchus in human body that branch off from the trachea into each lung. The air first traveled from mouth or nose travels through Larynx and Trachea respectively than gets into the Bronchi, which are also tube-like structures that split into a network of tubes, finishing with Bronchioles (smaller tubes), which connect the alveoli. The trachea, bronchi, and bronchioles collectively form tracheobronchial system, which consists up of three layers; mucosa, submucosa, and fibrocartilaginous layer. No gaseous exchange takes place in Bronchi; it only works as a passageway to the lungs.

What is Bronchioles?

Bronchioles are set of smaller tubes that work as a passageway in between Bronchus and Alveoli. They can be further divided into two types, respiratory bronchioles, and non-respiratory bronchioles. Respiratory bronchioles pass air flow, while non-respiratory bronchioles can exchange gaseous material. At the end of the tracheobronchial system, the smaller tubes that get it connected to the sac-like structures are bronchioles. Cartilage does not support these smaller tubes as in the case of Bronchi; they consist up of smooth muscles and elastic tissues lined with epithelium.

Bronchi vs. Bronchioles

  • Bronchi are the longer tubes that extend from the trachea, whereas bronchioles are the smaller tubes or passageways that are formed when bronchi are divided multiple times.
  • Bronchi possess large diameter than bronchioles.
  • There is only two bronchi (1 Bronchi), during multiple bronchioles in a human body.
  • Bronchi transport air to bronchioles, whereas bronchioles flow air into alveoli.
  • Bronchi are mainly formed of the cartilaginous layer, whereas bronchioles consist up of smooth muscles and elastic tissues lined with epithelium.
Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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