tonsils

Examples of tonsils in the following topics:

• Tonsils

  • The tonsils are small masses of secondary lymphoid tissue located in the pharynx.
  • There are four pairs of tonsils located within the pharynx.
  • The palatine tonsils are located in the sides of the oropharynx.
  • Captured antigens are presented to B and T cells within the tonsil, then the B cells migrate to germinal centers within the tonsil as an adaptive immune response is initiated.
  •  Tonsil removal (tonsillectomy) is a common procedure to treat swollen and infected lymph nodes (tonsillitis).

• Tonsillectomy

  • A tonsillectomy is a surgical procedure in which the tonsils are removed from either side of the throat.
  • Figure 1 shows a case of acute tonsillitis in children.
  • Figure 2 is a picture of the tonsils removed from a patient.
  • The generally accepted procedure for tonsillectomy involves separating and removing the tonsils from the subcapsular plane – a fascia of tissue that surrounds the tonsils.
  • After the tonsil is removed from its position, a snare can be used to make a small cut on the lower portion prior to removal of the tonsil.

• Pharynx

  • The pharyngeal tonsils, more commonly referred to as the adenoids, are lymphoid tissue structures located in the posterior wall of the nasopharynx.
  • The posterior wall of the nasopharynx holds the pharyngeal tonsils, which can be especially marked in childhood.
  • Superior to the pharyngeal tonsil, in the midline, an irregular flask-shaped depression of the mucous membrane sometimes extends upward; it is known as the pharyngeal bursa.
  • It opens anteriorly, through the isthmus faucium, into the mouth, and contains the palatine tonsil - another grouping of adenoid tissue.
  • The lateral walls are made up of the tonsil and associated tonsilar tissues.

• Pharynx

  • The adenoids (pharyngeal tonsils) are a mass of lymphatic tissue found in the roof of the nasopharynx.
  • The oropharynx contains the palatine tonsils, which are masses of lymphoid tissue found on the lateral walls of the oropharynx.
  • Compared to the adenoids of the nasopharynx, the palatine tonsils contain many folds (called crypts), and aren't ciliated like the adenoids are.
  • These tonsils are also occasionally removed in people with infection or enlargement.
  • Unlike the nasopharynx and oropharynx, there are no tonsils in the laryngopharynx.

• 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).
  • In addition to supporting B and T lymphocyte activation, other secondary lymphoid organs perform other unique functions, such as the spleen's ability to filter blood and the tonsil's ability to capture antigens in the upper respiratory tract.
  • The thymus and bone marrow are primary lymphoid tissue, while the lymph nodes, tonsils, and spleen are secondary lymphoid tissue.

• Glossopharyngeal (IX) Nerve

  • It receives general sensory fibers (ventral trigeminothalamic tract) from the tonsils, the pharynx, the middle ear, and the posterior 1/3 of the tongue.

• Structure of the Lymphatic System

  • Lymphoid tissue is found in many organs including the lymph nodes, as well as in the lymphoid follicles in the pharynx such as the tonsils.

• Brief Overview of Cranial Nerves

  • The glossopharyngeal nerve (IX): This nerve receives sensory information from the tonsils, the pharynx, the middle ear, and the rest of the tongue.

• Spleen

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

• Natural Killer Cells

  • NK cells differentiate and mature in the bone marrow, lymph nodes, spleen, tonsils and thymus, where they then enter into the bloodstream.