Digital Histology
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Trachea and primary bronchus

The walls of the trachea and primary (main) bronchi are identical, with both possessing cartilage rings. As the bronchi enter the lung, the rings are replaced by irregularly shaped cartilage plates. The highly cellular lamina propria is separated from the submucosa by elastic fibers, sometimes forming a distinct elastic lamina; though not clearly evident in this image. The trachea and primary bronchi are extrapulmonary and are part of the conducting portion of the respiratory system. 100x

Epithelium > <p>A tall pseudostratified columnar epithelium with cilia and goblet cells lines the trachea and primary bronchi.</p>

Epithelium >

A tall pseudostratified columnar epithelium with cilia and goblet cells lines the trachea and primary bronchi.
Basement membrane > <p>A prominent basement membrane is typical for these two passageways.</p>

Basement membrane >

A prominent basement membrane is typical for these two passageways.
Lamina propria > <p>The highly cellular lamina propria is composed of loose connecting tissue with large numbers of lymphocytes and plasma cells. An indistinct layer of elastic fibers and smooth muscle is present beneath the lamina propria. </p>

Lamina propria >

The highly cellular lamina propria is composed of loose connecting tissue with large numbers of lymphocytes and plasma cells. An indistinct layer of elastic fibers and smooth muscle is present beneath the lamina propria.

Submucosa > <p>The distinction between the lamina propria and submucosa is not well defined. The submucosa ends as it blends with the fibrous layer of the perichondrium.</p>

Submucosa >

The distinction between the lamina propria and submucosa is not well defined. The submucosa ends as it blends with the fibrous layer of the perichondrium.
Mixed glands > <p>Mixed glands, located in the submucosa, secrete both mucous and serous products. Their secretions moisten the surface of the epithelium as well provide a coating for these passageways that entrap inhaled dust and other particulate matter.</p>

Mixed glands >

Mixed glands, located in the submucosa, secrete both mucous and serous products. Their secretions moisten the surface of the epithelium as well provide a coating for these passageways that entrap inhaled dust and other particulate matter.
- Mucous component <p>Mixed glands, located in the submucosa, secrete both mucous and serous products. Their secretions moisten the surface of the epithelium as well provide a coating for these passageways that entrap inhaled dust and other particulate matter.</p>

- Mucous component

Mixed glands, located in the submucosa, secrete both mucous and serous products. Their secretions moisten the surface of the epithelium as well provide a coating for these passageways that entrap inhaled dust and other particulate matter.
- Serous component <p>Mixed glands, located in the submucosa, secrete both mucous and serous products. Their secretions moisten the surface of the epithelium as well provide a coating for these passageways that entrap inhaled dust and other particulate matter.</p>

- Serous component

Mixed glands, located in the submucosa, secrete both mucous and serous products. Their secretions moisten the surface of the epithelium as well provide a coating for these passageways that entrap inhaled dust and other particulate matter.
Cartilage > <p>Patency of the trachea and primary bronchi is maintained by a series of hyaline cartilage rings. A perichondrium surrounds this tissue.</p>

Cartilage >

Patency of the trachea and primary bronchi is maintained by a series of hyaline cartilage rings. A perichondrium surrounds this tissue.
Perichondrium <p>Patency of the trachea and primary bronchi is maintained by a series of hyaline cartilage rings. A perichondrium surrounds this tissue.</p>

Perichondrium

Patency of the trachea and primary bronchi is maintained by a series of hyaline cartilage rings. A perichondrium surrounds this tissue.
Image source > <p>This image was taken of a slide in the University of Michigan slide collection</p>

Image source >

This image was taken of a slide in the University of Michigan slide collection
Main SlideEpithelium > Basement membrane > Lamina propria > Submucosa > Mixed glands > - Mucous component - Serous componentCartilage > PerichondriumImage source >