From the Guidelines
The palatine tonsil lies between the palatoglossal fold and the palatopharyngeal fold, serving as a crucial lymphatic tissue in the immune system. This lymphatic tissue is part of Waldeyer's ring, which is a circular arrangement of lymphoid tissue in the pharynx that also includes the lingual tonsil, pharyngeal tonsil (adenoids), and tubal tonsils 1. The palatine tonsil serves an important immunological function as it helps detect and respond to pathogens entering the body through the mouth or nose. It contains crypts (deep invaginations) that increase its surface area, allowing for more efficient sampling of potential antigens. The palatine tonsil is covered by stratified squamous epithelium on its outer surface and contains numerous lymphoid follicles within its substance.
Some key features of the palatine tonsil include:
- Strategically positioned to serve as secondary lymphoid organs, initiating immune responses against antigens entering the body through the mouth or nose 1
- Greatest immunologic activity found between the ages of 3 and 10 years, resulting in the tonsils being most prominent during this period of childhood and subsequently demonstrating age-dependent involution 1
- Production of all 5 immunoglobulin (Ig) isotypes, with IgA being arguably the most important product of the tonsillar immune system 1
- Contains a system of specialized channels lined by “M” cells, which take up antigens into vesicles and transport them to the extrafollicular region or the lymphoid follicles 1
The palatine tonsil plays a vital role in the immune system, and its location between the palatoglossal fold and the palatopharyngeal fold allows it to effectively sample and respond to potential pathogens. As noted in the clinical practice guideline: tonsillectomy in children (update) 1, the tonsils are most prominent during childhood and tend to involute with age, which explains why tonsillectomies are more commonly performed in children than adults.
From the Research
Lymphatic Tissue Location
The lymphatic tissue in question is located between the palatoglossal fold and the palatopharyngeal fold.
Identification of Lymphatic Tissue
- The palatine tonsils are compact yet physiologically complex mucosa-associated lymphoid tissues that make up a portion of Waldeyer's ring 2.
- The palatine tonsils, nasopharyngeal tonsil (adenoid) and lingual tonsil constitute the major part of Waldeyer's ring or nasal-associated lymphoid tissue (NALT) 3.
- Human palatine tonsils and the nasopharyngheal tonsil are the largest components of the Waldeyer's ring 4.
Specific Lymphatic Tissue Between Folds
- The specific lymphatic tissue between the palatoglossal fold and the palatopharyngeal fold is the palatine tonsils, which are part of the Waldeyer's ring 2, 3.
- The distribution of lymphatics in human palatine tonsils was studied, and it was found that the palatine tonsils possess lymphatics in the parafollicular area, in the connective tissue septa, and in the capsules 5.