anatomyphysiologyblog - HISTOLOGICAL FEATURES OF TONSIL
Tonsils
Tonsils belong to the mucosa associated lymphoid tissue (MALT), but because they are incompletely encapsulated, they are considered organs too volition live on studied apart from the MALT. The tonsils found a lymphoid tissue that lies beneath, too inwards contact with, the epithelium of the initial part of the digestive tract. Depending on their location, tonsils inwards the oral fissure too throat are called palatine, pharyngeal, or lingual.
Palatine Tonsils
The 2 palatine tonsils are located inwards the lateral walls of the oral purpose of the pharynx. They are lined amongst a squamous stratified epithelium that oftentimes becomes too then densely infiltrated yesteryear lymphocytes that it may live on hard to recognize. The lymphoid tissue inwards these tonsils forms a band that contains costless lymphocytes too lymphoid nodules, mostly amongst germinal centers. Each tonsil has 10–20 epithelial invaginations that penetrate the tonsil deeply, forming crypts, whose lumens incorporate desquamated epithelial cells, alive too dead lymphocytes, too bacteria. Crypts may seem every bit purulent spots inwards tonsillitis. Separating the lymphoid tissue from subjacent structures is a band of dense connector tissue, the capsule of the tonsil. This capsule unremarkably acts every bit a barrier against spreading tonsillar infections.
Pharyngeal Tonsil
The pharyngeal tonsil is a unmarried tonsil situated inwards the superior— posterior part of the pharynx. It is covered yesteryear ciliated pseudostratified columnar epithelium typical of the respiratory tract, although areas of stratified epithelium tin too live on observed.
The pharyngeal tonsil is composed of pleats of mucosa too contains diffuse lymphoid tissue too lymphoid nodules. It has no crypts, too its capsule is thinner than the capsule of the palatine tonsils. Hypertrophied pharyngeal tonsils resulting from chronic inflammation are called adenoids.
Lingual Tonsils
The lingual tonsils are smaller too to a greater extent than numerous than the palatine too pharyngeal tonsils. They are situated at the base of operations of the natural language too are covered yesteryear stratified squamous epithelium. Each lingual tonsil has a unmarried crypt.
Waldeyer's Ring of Lymphoid Tissue
The lymphoid tissue that surrounds the opening into the respiratory too digestive systems forms a ring. The lateral purpose of the band is formed yesteryear the palatine tonsils too tubal tonsils (lymphoid tissue roughly the opening of the auditory metro inwards the lateral wall of the nasopharynx). The pharyngeal tonsil inwards the roof of the nasopharynx forms the upper part, too the lingual tonsil on the posterior tertiary of the natural language forms the lower part.
REFERENCES
Junqueira's Basic Histology: Text too Atlas, 13th Edition
Wheater's Functional Histology: H5N1 Text too Color Atlas, fifth Edition