the bronchi are considered to be part of the accessory bronchus.
the bronchi are considered to be part of the accessory bronchus.
the bronchi are considered to be part of the?
accessory bronchus
bullet::::- bronchus – a bronchi is a passage of airway in the respiratory system that conducts air into the lungs. the first bronchi to branch from the trachea are the right main bronchus and the left main bronchus. these are the widest and enter the lungs at each hilum, where they branch into narrower secondary bronchi known as lobar bronchi, and these branch into narrower tertiary bronchi known as segmental bronchi. further divisions of the segmental bronchi are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. the bronchi when too narrow to be supported by cartilage are known as bronchioles. no gas exchange takes place in the bronchi.
glossary of medicine
the primary bronchi, in each lung, which are the left and right bronchus, give rise to secondary bronchi known as lobar bronchi. these in turn give rise to tertiary bronchi ("tertiary" meaning "third"), known as segmental bronchi. the segmentary bronchi subdivide into fourth order, fifth order and sixth order segmental bronchi before dividing into the bronchioles. these are histologically distinct from the bronchi in that their walls do not have hyaline cartilage and they have club cells in their epithelial lining. the epithelium starts as a simple ciliated columnar epithelium and changes to simple ciliated cuboidal epithelium as the bronchioles decreases in size. the diameter of the bronchioles is often said to be less than 1 mm, though this value can range from 5 mm to 0.3 mm. as stated, these bronchioles do not have hyaline cartilage to maintain their patency. instead, they rely on elastic fibers attached to the surrounding lung tissue for support. the inner lining (lamina propria) of these bronchioles is thin with no glands present, and is surrounded by a layer of smooth muscle. as the bronchioles get smaller they divide into terminal bronchioles. these bronchioles mark the end of the conducting zone, which covers the first division through the sixteenth division of the respiratory tract. alveoli only become present when the conducting zone changes to the respiratory zone, from the sixteenth through the twenty-third division of the tract.
bronchiole