What is behind the tonsils

Except for those who study medicine and have a relatively good understanding of the structure of the human body, few people can clearly know the location of each organ in their body. Tonsils are located in people's necks. Some people often have symptoms of their tonsils when they are anxious, angry, or have a cold or fever, but people know very little about what is behind the tonsils. Let’s learn about the organs near the tonsils.

1. Tonsils

The palatine tonsils are a pair of flat oval lymphoid organs located in the tonsillar fossa. Tonsillar fossa: a triangular depression in the lateral wall of the oropharynx between the palatopharyngeal and palatoglossal arches. The mucosal epithelium sinks into the substance to form a non-depressed pit, called the tonsillar pit.

The anterior and lower part of the tonsil is covered by the palatoglossal arch, and the uncovered upper part is surrounded by the tonsillar capsule composed of connective tissue, which is connected to the pharyngeal muscles only by loose connective tissue. This is often the site of peritonsillar abscess formation. The pharyngeal lymphatic ring is composed of the palatine tonsils, pharyngeal tonsils, Eustachian tonsils, and lingual tonsils.

2. Structural classification

1. Palatine tonsils

The palatine tonsils are oval in shape, with one mucosal surface covered with stratified squamous epithelium, which sinks into the lamina propria to form crypts with 10 to 30 branches. There are a large number of diffuse lymphoid tissues and lymph nodules in the lamina propria surrounding the crypts. The stratified squamous epithelium deep in the crypt contains many T cells, B cells, plasma cells and a small number of macrophages and Langerhans cells, which is called the epithelial infiltrate. There are also some post-capillary venules in the epithelium, which are the main channels for lymphocytes to enter and exit the epithelium. There are many tunnel-like intercellular channels between epithelial cells. Some superficial channels open directly to the surface, and some channel openings are covered with a flat microfold cell (microfold cell, Mcell). Epithelial spaces are populated by T cells, which migrate and replace frequently. Intraepithelial plasma cells are often distributed near fenestrated capillaries, facilitating the secreted antibodies to enter the bloodstream. The palatine tonsils of children are more developed, and their lamina propria contain a large number of diffuse lymphoid tissue and lymph nodules. Their number and degree of development are closely related to antigen stimulation. B cells in tonsil lymphoid tissue account for 60% of the total lymphocytes, T cells account for 38.5%, and there are a small number of K cells and NK cells. There are more T cells in the diffuse lymphoid tissue, as well as scattered plasma cells, B cells and some post-capillary venules. Lymph nodules are often numerous and large, indicating that the tonsils have a close relationship with the body's humoral immune function. There are also some small lymphatic vessels in the lamina propria, through which lymphocytes can enter the lymph.

2. Pharyngeal tonsils

Pharyngeal tonsils, also known as adenoids, are located on the posterior wall of the pharynx. The surface is covered with pseudostratified ciliated columnar epithelium and has no crypts. The mucosa forms some longitudinal folds, there are many lymphoid tissues in the lamina propria, lymphocyte infiltration is also common in the epithelium, and the epithelium in the infiltrated part often becomes stratified squamous epithelium.

3. Lingual tonsils

The lingual tonsils are located at the base of the tongue and the anterior wall of the pharynx. The surface is covered with stratified squamous epithelium and some shallow crypts. There are lymphocyte infiltrations in the epithelium, and the lamina propria contains some lymph nodules and diffuse lymphoid tissue, which often make the tongue mucosa face the surface.