Palatine tonsil

Palatine tonsils, commonly called the tonsils and occasionally called the faucial tonsils, are tonsils located on the left and right sides at the back of the throat, which can often be seen as flesh-colored, pinkish lumps. Tonsils only present as 'white lumps' if they are inflamed or infected with symptoms of exudates (pus drainage) and severe swelling.Lymphatic systemThe mouth cavity. The cheeks have been slit transversely and the tongue pulled forward.Throat after tonsillectomyAnterior photograph of the oral cavity showing palatine tonsils (inflamed) and uvula.Open mouth with no visible palatine tonsils.Palatine tonsil Palatine tonsils, commonly called the tonsils and occasionally called the faucial tonsils, are tonsils located on the left and right sides at the back of the throat, which can often be seen as flesh-colored, pinkish lumps. Tonsils only present as 'white lumps' if they are inflamed or infected with symptoms of exudates (pus drainage) and severe swelling. Tonsillitis is an inflammation of the tonsils and will often, but not necessarily, cause a sore throat and fever. In chronic cases tonsillectomy may be indicated. The palatine tonsils are located in the isthmus of the fauces, between the palatoglossal arch and the palatopharyngeal arch of the soft palate. The palatine tonsil is one of the mucosa-associated lymphoid tissues (MALT), located at the entrance to the upper respiratory and gastrointestinal tracts to protect the body from the entry of exogenous material through mucosal sites. In consequence it is a site of, and potential focus for, infections, and is one of the chief immunocompetent tissues in the oropharynx. It forms part of the Waldeyer's ring, which comprises the adenoid, the paired tubal tonsils, the paired palatine tonsils and the lingual tonsils. From the pharyngeal side, they are covered with a stratified squamous epithelium, whereas a fibrous capsule links them to the wall of the pharynx. Through the capsule pass trabecules that contain small blood vessels, nerves and lymphatic vessels. These trabecules divide the tonsil into lobules. The nerves supplying the palatine tonsils come from the maxillary division of the trigeminal nerve via the lesser palatine nerves, and from the tonsillar branches of the glossopharyngeal nerve. The glossopharyngeal nerve continues past the palatine tonsil and innervates the posterior 1/3 of the tongue to provide general and taste sensation. This nerve is most likely to be damaged during a tonsillectomy, which leads to reduced or lost general sensation and taste sensation to the posterior third of the tongue. Blood supply is provided by tonsillar branches of five arteries: the dorsal lingual artery (of the lingual artery), ascending palatine artery (of the facial artery), tonsillar branch (of the facial artery), ascending pharyngeal artery (of the external carotid artery), and the lesser palatine artery (a branch of the descending palatine artery, itself a branch of the maxillary artery).The tonsils venous drainage is by the peritonsillar plexus, which drain into the lingual and pharyngeal veins, which in turn drain into the internal jugular vein. Palatine tonsils consist of approximately 15 crypts, which result in a large internal surface. The tonsils contain four lymphoid compartments that influence immune functions, namely the reticular crypt epithelium, the extrafollicular area, the mantle zones of lymphoid follicles, and the follicular germinal centers. In human palatine tonsils, the very first part exposed to the outside environment is tonsillar epithelium. Tonsillar (relating to palatine tonsil) B cells can mature to produce all the five major Immunoglobulin (Ig, aka antibody) classes. Furthermore, when incubated in vitro with either mitogens or specific antigens, they produce specific antibodies against diphtheria toxoid, poliovirus, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and the lipopolysaccharide of E. coli. Most Immunoglobulin A produced by tonsillar B cells in vitro appears to be 7S monomers, although a significant proportion may be l0S dimeric IgA. In addition to humoral immunity elicited by tonsillar and adenoidal B cells following antigenic stimulation, there is considerable T-cell response in palatine tonsils. Thus, natural infection or intranasal immunization with live, attenuated rubella virus vaccine has been reported to prime tonsillar lymphocytes much better than subcutaneous vaccination. Also, natural infection with varicella zoster virus has been found to stimulate tonsillar lymphocytes better than lymphocytes from peripheral blood.