Tonsils are secondary lymphoid organs in the oropharyngeal mucosa. Primary lymphoid organs include the thymus and bone marrow. The tonsils are a type of mucosa associated lymphoid tissue, abbreviated MALT, which are found in mucosal surfaces. There are four kinds of tonsillar structures. Top to bottom, these are the pharyngeal, tubal, palatine and lingual tonsils, which, together with small amounts of lymphatic tissue scattered throughout the pharynx’s mucosal lining, make an incomplete ring of lymphoid tissue called Waldeyer’s Ring.
The pharyngeal tonsil is also called the adenoid, and you have one of these. The adenoid is found where the nasal cavity meets the throat, next to the eustachian tube. It “screens” the air that enters your nostrils. Your adenoid grows until you are five, then shrinks at age 7. In adulthood, it’s very small. The adenoid is different from the other tonsils in that it has no crypts, which are invaginations in the surface of a tonsil.
You have tubal tonsils, also called Gerlach’s tonsils, on either side of the adenoid. They are often hard to see except when the adenoid is removed. They are underneath the mucosa of the eustachian tube and torus tubarius and in the Rosenmüller fossa.
You have two palatine tonsils. These are the largest of the tonsils and are readily visible on either side of the back of your throat, especially when they’re inflamed. They’re found between the palatoglossus arch and the palatopharyngeal arch, in a cavity called the isthmus of the fauces. The isthmus of the fauces is bound by the palatoglossal arches laterally, the soft palate superiorly, and the tongue inferiorly. The palatine tonsils have many deep and branching crypts, which contain lymphocytes. These crypts increase the probability of exposure of foreign antigens to the crypts’ lymphatic tissue. Interestingly, your tonsils can change and become more cryptic in your late teens and early 20s, and they shrink as you age.
You have one lingual tonsil, made up of small bumps on the most posterior part of the tongue’s base. This lymphoid tissue has a huge variety of sizes and shapes.
The four kinds of tonsils play an immune function, serving as a first line of defense against ingested or inhaled pathogens, since they’re at the gateway to our respiratory and digestive tract.
You’ve probably experienced tonsillitis at some point, meaning that your palatine tonsils were inflamed. This could have been the result of a throat infection. You may have had a fever, hoarseness, dysphagia, or trouble swallowing, and a white or yellow coating on your tonsils.
Another common tonsil-related problem are tonsilloliths, or tonsils stones. These form when matter trapped in tonsil crypts solidifies. They are mostly made up of calcium, which is why they are white or cream in colour, but have a putrid odor due to hydrogen sulfide and methyl mercaptan contents.