Semifine cross-section of trachea stained with toluidine blue and observed with the objective of 40x. In this image we can see the different layers that constitute the trachea: mucous, constituted by pseudostratified prismatic epithelium, and submucous, formed by connective tissue containing abundant blood vessels. We can also view part of a cartilage and the external adipose tissue. Details of the mucous and the cartilage are observed in other microphotographies (zones framed in red and blue, respectively)