The nasal cavity is separated into two spaces, or fossae, by the nasal septum.
The nasal septum can be seen along the midline.
The nasal turbinates project into the nasal cavity in order to help increase the total available surface area.
Both the paranasal sinuses, as well as the majority of the nasal cavity, are lined with respiratory mucosa.
Only the roof of the nasal cavity is lined with olfactory mucosa instead.
This image of a human’s nasal mucosa, at 10x magnification, was prepared with Alcian blue and Van Gieson stains.
If we zoom in, to 40x magnification, we can see that the epithelium consists of pseudostratified ciliated columnar cells, along with many goblet cells that can be easily identified in light blue, because of the Alcian Blue stain.
This epithelium is also referred to as respiratory epithelium and generally can be found in the conducting portions of the respiratory tract.
The supporting connective tissue called the lamina propria is deep to the epithelium and contains many blood vessels and seromucous glands.
If we compare the respiratory epithelium to the olfactory epithelium, we can see that the olfactory epithelium also has pseudostratified columnar cells, but it’s significantly thicker and is composed of a combination of olfactory, sustentacular, and basal cells.
The surface of the olfactory epithelium is also lined with modified cilia that function as olfactory receptors, which allows the olfactory cells to sense smells.
Moving on to the larynx, this image is a low power, coronal section of the larynx.
There are two pairs of folds within the larynx, the upper folds are the vestibular folds (or false vocal cords), and the lower folds are the actual vocal folds, (or true vocal cords).
Between the folds on each side are narrow spaces simply called ventricles.
Each true vocal cord will need relatively large muscles in order to move the vocal cords for speech.
These muscles, called the vocalis muscles are stained darker within the vocal folds.
The long structures on both sides of the larynx are portions of the thyroid cartilage, and the cricoid cartilage is partially seen at the bottom as well.
Both of these support structures contain a large amount of hyaline cartilage that can be identified by their dark glassy appearance under higher magnification.
The structure at the top is this image is the epiglottis.
Now, let’s take a closer look at an upper vestibular fold stained with Haemotoxylin and Eosin or H&E for short.
Within the fold, there are many seromucous glands that help trap contaminants as well as increasing moisture in the air that’s breathed in.