Tonsil
From Wikipedia, the free encyclopedia
- For the structure in the cerebellum, see cerebellar tonsil.
The tonsils are areas of lymphoid tissue on either side of the throat. An infection of the tonsils is called tonsillitis. Most commonly, the term "tonsils" refers to the palatine tonsils that can be seen in the back of the throat.
As with other organs of the lymphatic system, the tonsils act as part of the immune system to help protect against infection. In particular, they are believed to be involved in helping fight off pharyngeal and upper respiratory tract infections.
Tonsils in humans include, from superior to inferior:
| Name | Epithelium | Capsule? | Crypts? | Location |
| adenoids (also termed "pharyngeal tonsils") | ciliated pseudostratified (respiratory epithelium) | No | No | roof of pharynx |
| palatine tonsils | non-keratinized stratified squamous | Yes | Yes | sides of pharynx between glossopalatine and pharyngopalatine arches |
| lingual tonsils | non-keratinized stratified squamous | No | Yes | behind terminal sulcus (tongue) |
Together this set of lymphatic tissue is known as Waldeyer's tonsillar ring.
Tonsils tend to reach their largest size near puberty, and they gradually undergo atrophy thereafter. However, they are largest relative to the diameter of the throat in young children, and tonsillectomy (surgical removal of tonsils) may be indicated if they are obstructing the airway or interfering with swallowing.
[edit] See also
[edit] External links
Bone marrow | Thymus (Hassall's corpuscles) | Spleen (White pulp, Periarteriolar lymphoid sheaths, Marginal zone, Red pulp) | Tonsils/Waldeyer's tonsillar ring (Palatine, Lingual, Adenoid)
Mucosa-associated lymphoid tissue: Gut-associated lymphoid tissue | Peyer's patches
Lymph nodes: Subcapsular sinus | Paracortex | Lymph vessels
Lymph | Lymphocytes | High endothelial venules | Immune system
