Table of Contents
General information on Tonsils Histology:
The tonsils Histology, which includes the palatine, pharyngeal, and lingual tonsils, collectively form what is known as the Waldeyer ring. They are clusters of lymphoid nodules with germinal centers and are positioned at the entrance to the oral pharynx. Their strategic locations make them intercept both airborne and ingested antigens, prompting an immune response. Specific chemokines guide the distribution of B and T lymphocytes within each tonsil. Together, tonsils respond to bacterial and viral infections by enlarging and producing IgA antibodies against the invading pathogens.
Palatine Tonsils Histology:
- Palatine tonsils are found bilaterally at the border of the oral cavity and oral pharynx.
- Palatine tonsils are enclosed by a dense fibrous capsule.
- The surface of palatine tonsils is covered with a nonkeratinized stratified squamous epithelium that forms deep crypts.
- These crypts often contain various materials, including food debris, dead cells, bacteria, and antigens.
- The Palatine tonsil’s parenchyma consists of multiple lymphoid nodules, many with germinal centers, indicating B-cell activity.
Pharyngeal Tonsil Histology:
- The single pharyngeal tonsil is located on the roof of the nasal pharynx.
- It has a thinner capsule compared to the palatine tonsils.
- Instead of crypts, it features shallow, longitudinal pleats, which receive ducts from seromucous glands.
- The superficial surface of the pharyngeal tonsil is covered by a pseudostratified ciliated columnar epithelium mixed with patches of stratified squamous epithelium.
- The parenchyma of the pharyngeal tonsil is composed of lymphoid nodules, some of which have germinal centers. When this tonsil is inflamed, it is called the adenoid.
Lingual Tonsil Histology :
- Found on the dorsal surface of the posterior third of the tongue.
- Superficially covered by nonkeratinized stratified squamous epithelium.
- Has a delicate capsule separating it from underlying connective tissue.
- Contains numerous crypts receiving ducts from mucous minor salivary glands.
- Composed of lymphoid nodules, often with germinal centers.
