adenoid

(noun)

One of the two 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. They may obstruct normal breathing and make speech difficult when swollen—a condition often called adenitis.

Related Terms

Examples of adenoid in the following topics:

  • Pharynx

    • The adenoids (pharyngeal tonsils) are a mass of lymphatic tissue found in the roof of the nasopharynx.
    • The adenoids play a minor role in embyonic development and have a minor role in producing T-lymphocytes for the immune system after birth.
    • While loss of the adenoids does not make a significant difference in immune system function, the procedure occasionally has complications.
    • Above the adenoid, in the midline, is an irregular flask-shaped depression of the mucous membrane called the pharyngeal bursa.
    • Compared to the adenoids of the nasopharynx, the palatine tonsils contain many folds (called crypts), and aren't ciliated like the adenoids are.

  • Tonsillectomy

    • It is performed in response to cases of repeated occurrence of acute tonsillitis or adenoiditis, obstructive sleep apnea, nasal airway obstruction, snoring, or peritonsillar abscess.
    • For children, the adenoids are removed at the same time, a procedure called adenoidectomy.
    • A mouth gag is used to prop the mouth open; if an adenoidectomy is also being performed, the adenoids are first removed with a curette; the nasopharynx is then packed with sterile gauze.

  • Tonsils

    • For example, the adenoids and tubal tonsils are covered with the ciliated psuedostratified columnar epithelium of the nasopharynx, while the palatine and lingual tonsils are made up of the non-keratinized stratified squamous epithelium of the oropharynx.
    • Chronic infection of the adenoids can cause adenoid hypertrophy, increases in cell size from repeated damage.

  • Pharynx

    • The pharyngeal tonsils, more commonly referred to as the adenoids, are lymphoid tissue structures located in the posterior wall of the nasopharynx.
    • It opens anteriorly, through the isthmus faucium, into the mouth, and contains the palatine tonsil—another grouping of adenoid tissue.

  • Cytotoxic T Lymphocytes and Mucosal Surfaces

    • Lymph moves about the body through the lymphatic system, which is made up of vessels, lymph ducts, lymph glands, and organs such as tonsils, adenoids, thymus, and spleen.

  • Lymphoid Tissue

    • It is found mainly in the lymph nodes, but also in the lymphoid follicles in tonsils, Peyer's patches, spleen, adenoids, skin, and other areas associated with the mucosa-associated lymphoid tissue (MALT).

  • Regulating Immune Tolerance

    • Processed antigens displayed on APCs are detected by T cells in the MALT and at various mucosal induction sites, such as the tonsils, adenoids, appendix, or the mesenteric lymph nodes of the intestine.

  • Spleen

    • White pulp is secondary lymphoid tissue that is similar to that in the adenoid tonsils.

  • Cells and Organs of the Immune System

    • The key primary lymphoid organs of the immune system include the thymus and bone marrow, as well as secondary lymphatic tissues including spleen, tonsils, lymph vessels, lymph nodes, adenoids, skin, and liver.