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Visualising the interior of the bronchi through a bronchoscope passed through the mouth and trachea, procedure is called bronchoscopy. The carina of the trachea is a hook shaped process projecting backward from the lower margin of lowest tracheal ring. It helps to divide the trachea into two primary bronchi.
The secondary bronchi divide further into tertiary bronchi, (also known as segmental bronchi), each of which supplies a bronchopulmonary segment. A bronchopulmonary segment is a division of a lung separated from the rest of the lung by a septum of connective tissue. This property allows a bronchopulmonary segment to be surgically removed ...
The lobar bronchi branch into tertiary bronchi also known as segmental bronchi and these supply air to the further divisions of the lobes known as bronchopulmonary segments. Each bronchopulmonary segment has its own (segmental) bronchus and arterial supply. [8] Segments for the left and right lung are shown in the table. [5]
The right lung has three lobes – upper, middle, and lower (or superior, middle, and inferior), and the left lung has two – upper and lower (or superior and inferior), plus a small tongue-shaped portion of the upper lobe known as the lingula. Each lobe is further divided up into segments called bronchopulmonary segments. Each lung has a ...
Segmentectomies are the surgical removal of bronchopulmonary segments and often involve the removal of two adjacent segments. The pulmonary arterial branches to the segments are first identified then divided. Next, stapling is used to divide the segmental bronchi and separate the segments from the lung. [13]
Further divisions of the segmental bronchi (1 to 6 mm in diameter) [7] are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. [ 8 ] [ 9 ] Compared to the 23 number (on average) of branchings of the respiratory tree in the adult human, the mouse has only about 13 such branchings.
A decrease in diameter is called bronchoconstriction, which is the tightening of the smooth muscle surrounding the bronchi and bronchioles due to and stimulated by histamine, parasympathetic nerves, cold air, chemical irritants, excess mucus production, viral infections, and other factors to decrease air flow. Bronchoconstriction can result in ...
Alveolar pressure (PA) at end expiration is equal to atmospheric pressure (0 cm H 2 O differential pressure, at zero flow), plus or minus 2 cm H 2 O (1.5 mmHg) throughout the lung. On the other hand, gravity causes a gradient in blood pressure between the top and bottom of the lung of 20 mmHg in the erect position (roughly half of that in the ...