In this note, we are going to discuss the anatomy and function of the tonsils, that form the so-called Waldeyer’s ring.

In this note, we are going to discuss the anatomy and function of the tonsils, that form the so-called Waldeyer’s ring.

Waldeyer’s ring is composed of four tonsillar structures:

• Pharyngeal tonsil

• Tubal tonsils

• Palatine tonsils

• Lingual tonsil

In addition, it includes tiny accumulations of lymphatic tissue located within the mucosal lining of the pharynx, known as mucosa-associated lymphoid tissue (MALT).

The tonsils are clusters of lymphoid tissue composed of small cellular collections known as lymphoid nodules. These nodules can be found in various organs of the immune system. Each nodule consists of reticular cells and fibers that form a three-dimensional network, within which numerous lymphocytes are located.

Let’s examine each tonsil in greater detail.

Palatine tonsil

There are two palatine tonsils – left and right,

each located within a tonsillar fossa, bordered anteriorly by the palatoglossal arch

and posteriorly by the palatopharyngeal arch.

The palatine tonsils are covered by stratified non-keratinized squamous epithelium and contain numerous invaginations, known as crypts.

These crypts play a role in trapping and exposing antigens to the immune cells within the tonsils. The lateral aspect of the tonsil is adjacent to the pharyngeal fascia, from which trabeculae extend medially into the lymphoid tissue of the organ.

Lingual tonsil

The lingual tonsils are numerous collections of lymphoid nodules located within the root of the tongue. The mucous membrane covering these tonsils has crypts, which are lined by stratified non-keratinized squamous epithelium infiltrated by lymphocytes.

Pharyngeal tonsil

The pharyngeal tonsil, also known as the nasopharyngeal tonsil or adenoid, is located within the roof of the nasopharynx, between the pharyngeal openings of the auditory tubes. Its primary function is to screen the air entering via the nasal route. Unlike other tonsils, the pharyngeal tonsil has no crypts and is covered by pseudostratified ciliated columnar epithelium, commonly known as respiratory epithelium.

Tubal tonsil

The tubal tonsils, also known as Gerlach’s tonsils, are located within the pharyngeal recess of the nasopharynx, posterior to the torus tubarius, which borders the pharyngeal opening of the auditory tube. These structures are lined with respiratory epithelium and contain crypts that are infiltrated by lymphatic tissue.

Golosary

Tonsils. Waldeyer’s ring

Pharyngeal tonsil

tonsilla pharyngea

Tubal tonsil

tonsilla tubaria

Palatine tonsil

tonsilla palatina

Lingual tonsil

tonsilla lingualis

Palatoglossal arch

arcus palatoglossus

Palatopharyngeal arch

arcus palatopharyngeus

Tonsillar crypts

cryptae tonsillares

Pharyngobasilar fascia

fascia pharyngobasilaris

Torus tubarius

torus tubarius