Ok...this is what one IS:
• Adenoid
Adenoids, or pharyngeal tonsils, are folds of lymphatic tissue covered by ciliated epithelium. They are found in the roof and posterior wall of the nasopharynx at the back of the throat behind the uvula.
But what in hell does it DO?
Oh...this is what they do.
Function
Adenoids are part of the immune system. Like all lymphoid tissue, they trap infectious agents like viruses and bacteria, and they produce antibodies. Since the adenoids are located at the back of the nasal airway, they provide defense against inhaled substances. This function decreases with age as the adenoids shrink. Because adenoids do ordinarily shrink by late childhood, the problems caused by enlarged adenoids rarely occur in adults.
There is very little lymphoid tissue in the nasopharynx of young babies; humans are born without substantial adenoids. The mat of lymphoid tissue called adenoids starts to get sizable during the first year of life. Just how big the adenoids become is quite variable between individual children. Enlarged adenoids can become nearly the size of a ping pong ball and completely block airflow through the nasal passages. Even if enlarged adenoids are not substantial enough to physically block the back of the nose, they can obstruct airflow enough so that breathing through the nose requires an uncomfortable amount of work, and inhalation occurs instead through an open mouth. Adenoids can also obstruct the nasal airway enough to affect the voice without actually stopping nasal airflow altogether.
Nasal blockage is determined by least two factors: 1) the size of the adenoids, and 2) the size of the nasal pharynx passageway. The adenoid usually reaches is greatest size by about age 5 years or so, and then fades away ("atrophies") by late childhood - generally by the age of 7 years. The lymphoid tissue remains under the mucosa of the nasopharynx, and could be seen under a microscope if the area was biopsied, but the mass is so reduced in size that the roof of the nasopharynx becomes flat rather than mounded. Just as the size of the adenoids is variable between individuals, so is the age at which adenoids atrophy.
The adenoids, like all lymphoid tissue, enlarge when infected. Although lymphoid tissue does act to fight infection, sometimes bacteria and viruses can lodge within it and survive. Chronic infection, either viral or bacterial, can keep the pad of adenoids enlarged for years, even into adulthood. Some viruses, such as the Epstein-Barr Virus, can cause dramatic enlargement of lymphoid tissue. Primary or reactivation infections with Epstein Barr Virus, and certain other bacteria and viruses, can even cause enlargement of the adenoidal pad in an adult whose adenoids had previously become atrophied.
Adenoids are rarely visible on physical examination without the skilled use of mirrors or fiber optic endoscopes. A lateral X-ray view of the skull taken to show soft tissue density can show the adenoids, as can other imaging studies such as CT scans and MRI.
Now I can forget about the little smeggers again.