Palatine tonsil

Last updated
Palatine tonsil
Illu mouth.jpg
Mouth (oral cavity)
Tonsils diagram.jpg
The palatine tonsils with the soft palate, uvula, and tongue visible.
Details
Precursor Pharyngeal arches [1]
System Immune system (Lymphatic system)
Artery Tonsillar branch of the facial artery
Nerve Tonsillary branches of lesser palatine nerves
Identifiers
Latin tonsilla palatina
MeSH D014066
TA98 A05.2.01.011
TA2 2853, 5181
FMA 9610
Anatomical terminology

Palatine tonsils, commonly called the tonsils and occasionally called the faucial tonsils, [2] 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.

Contents

Tonsillitis is an inflammation of the tonsils and will often, but not necessarily, cause a sore throat and fever. [3] In chronic cases, tonsillectomy may be indicated. [4]

Structure

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. [5] [6] 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. [7] 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.

Blood supply and innervation

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. [7] 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. [8] [9]

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. [7]

Tonsillar crypts

Low-power microscope magnification of a cross-section through one of the tonsillar crypts (running diagonally) as it opens onto the surface of the throat (at the top). Stratified epithelium (e) covers the throat's surface and continues as a lining of the crypt. Beneath the surface are numerous nodules (f) of lymphoid tissue. Many lymph cells (dark-colored region) pass from the nodules toward the surface and will eventually mix with the saliva as salivary corpuscles (s). Gray1027.png
Low-power microscope magnification of a cross-section through one of the tonsillar crypts (running diagonally) as it opens onto the surface of the throat (at the top). Stratified epithelium (e) covers the throat's surface and continues as a lining of the crypt. Beneath the surface are numerous nodules (f) of lymphoid tissue. Many lymph cells (dark-colored region) pass from the nodules toward the surface and will eventually mix with the saliva as salivary corpuscles (s).

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. [10]

Function

Local immunity

Tonsillar (relating to palatine tonsil) B cells can mature to produce all the five major immunoglobulin (Ig, aka antibody) classes. [6] 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. [6] 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.

Cytokine action

Cytokines are humoral immunomodulatory proteins or glycoproteins which control or modulate the activities of target cells, resulting in gene activation, leading to mitotic division, growth and differentiation, migration, or apoptosis. They are produced by wide range of cell types upon antigen-specific and non-antigen specific stimuli. It has been reported by many studies that the clinic outcome of many infectious, autoimmune, or malignant diseases appears to be influenced by the overall balance of production (profiles) of pro-inflammatory and anti-inflammatory cytokines. Therefore, determination of cytokine profiles in tonsil study will provide key information for further in-depth analysis of the cause and underlying mechanisms of these disorders, as well as the role and possible interactions between the T- and B-lymphocytes and other immunocompetent cells. [11]

The cytokine network represents a very sophisticated and versatile regulatory system that is essential to the immune system for overcoming the various defense strategies of microorganisms. Through several studies, the Th1 and Th2 cytokines and cytokine mRNA are both detectable in tonsillar hypertrophy (or obstructive sleep apnea, OSA) and recurrent tonsillitis groups. It showed that human palatine tonsil is an active immunological organ containing a wide range of cytokine-producing cells. Both Th1 and Th2 cells are involved in the pathophysiology of TH and RT conditions. Indeed, human tonsils persistently harbor microbial antigens even when the subject is asymptomatic of ongoing infection. It could also be an effect of ontogeny of the immune system.

Clinical significance

The pathogenesis of infectious/inflammatory disease in the tonsils most likely has its basis in their anatomic location and their inherent function as organ of immunity, processing infectious material, and other antigens and then becoming, paradoxically, a focus of infection/inflammation. No single theory of pathogenesis has yet been accepted, however. Viral infection with secondary bacterial invasion may be one mechanism of the initiation of chronic disease, [12] but the effects of the environment, host factors, the widespread use of antibiotics, ecological considerations, and diet all may play a role. [13] A recent cross-sectional study revealed a high rate of prevalent virus infections in non-acutely ill patients undergoing routine tonsillectomy. However, none of the 27 detected viruses showed positive association to the tonsillar disease. [14]

In children, the tonsils are common sites of infections that may give rise to acute or chronic tonsillitis. However, it is still an open question whether tonsillar hypertrophy is also caused by a persistent infection. Tonsillectomy is one of the most common major operations performed on children. The indications for the operation have been complicated by the controversy over the benefits of removing a chronically infected tissue and the possible harm caused by eliminating an important immune inductive tissue. [15] [16]

The information that is necessary to make a rational decision to resolve this controversy can be obtained by understanding the immunological potential of the normal palatine tonsils and comparing these functions with the changes that occur in the chronically diseased counterparts.

Acute tonsillitis

A medical animation still that shows tonsillitis. SAG Acute-Tonsillitis 191010 01 (1).jpg
A medical animation still that shows tonsillitis.

Tonsillitis is the inflammation of tonsils. Acute tonsillitis is the most common manifestation of tonsillar disease. It is associated with sore throat, fever and difficulty swallowing. [17] The tonsils may appear normal sized or enlarged but are usually erythematous. Often, but not always, exudates can be seen. Not all these signs and symptoms are present in every patient.

Recurrent tonsillitis

Recurrent infection has been variably defined as from four to seven episodes of acute tonsillitis in one year, five episodes for two consecutive years or three episodes per year for 3 consecutive years. [18] [19]

Tonsillar hypertrophy

Tonsillar hypertrophy is the enlargement of the tonsils, but without the history of inflammation. Obstructive tonsillar hypertrophy is currently the most common reason for tonsillectomy. [15] These patients present with varying degrees of disturbed sleep which may include symptoms of loud snoring, irregular breathing, nocturnal choking and coughing, frequent awakenings, sleep apnea, dysphagia and/or daytime hypersomnolence. These may lead to behavioral/mood changes in patients and facilitate the need for a polysomnography in order to determine the degree to which these symptoms are disrupting their sleep. [20] [21]

Additional images

Related Research Articles

<span class="mw-page-title-main">Immune system</span> Biological system protecting an organism against disease

The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli. The adaptive immune system provides a tailored response to each stimulus by learning to recognize molecules it has previously encountered. Both use molecules and cells to perform their functions.

<span class="mw-page-title-main">Streptococcal pharyngitis</span> Medical condition

Streptococcal pharyngitis, also known as streptococcal sore throat, is pharyngitis caused by Streptococcus pyogenes, a gram-positive, group A streptococcus. Common symptoms include fever, sore throat, red tonsils, and enlarged lymph nodes in the front of the neck. A headache and nausea or vomiting may also occur. Some develop a sandpaper-like rash which is known as scarlet fever. Symptoms typically begin one to three days after exposure and last seven to ten days.

<span class="mw-page-title-main">Pharyngitis</span> Inflammation of the back of the throat

Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice. Symptoms usually last 3–5 days, but can be longer depending on cause. Complications can include sinusitis and acute otitis media. Pharyngitis is a type of upper respiratory tract infection.

<span class="mw-page-title-main">Tonsillectomy</span> Surgical removal of the tonsils

Tonsillectomy is a surgical procedure in which both palatine tonsils are fully removed from the back of the throat. The procedure is mainly performed for recurrent tonsillitis, throat infections and obstructive sleep apnea (OSA). For those with frequent throat infections, surgery results in 0.6 fewer sore throats in the following year, but there is no evidence of long term benefits. In children with OSA, it results in improved quality of life.

<span class="mw-page-title-main">Rheumatic fever</span> Post-streptococcal inflammatory disease

Rheumatic fever (RF) is an inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a streptococcal throat infection. Signs and symptoms include fever, multiple painful joints, involuntary muscle movements, and occasionally a characteristic non-itchy rash known as erythema marginatum. The heart is involved in about half of the cases. Damage to the heart valves, known as rheumatic heart disease (RHD), usually occurs after repeated attacks but can sometimes occur after one. The damaged valves may result in heart failure, atrial fibrillation and infection of the valves.

<span class="mw-page-title-main">Adenoid</span> Type of tonsil

In anatomy, the pharyngeal tonsil, also known as the nasopharyngeal tonsil or adenoid, is the superior-most of the tonsils. It is a mass of lymphatic tissue located behind the nasal cavity, in the roof of the nasopharynx, where the nose blends into the throat. In children, it normally forms a soft mound in the roof and back wall of the nasopharynx, just above and behind the uvula.

<span class="mw-page-title-main">Adenoidectomy</span> Surgical removal of the adenoid

Adenoidectomy is the surgical removal of the adenoid for reasons which include impaired breathing through the nose, chronic infections, or recurrent earaches. The effectiveness of removing the adenoids in children to improve recurrent nasal symptoms and/or nasal obstruction has not been well studied. The surgery is less commonly performed in adults in whom the adenoid is much smaller and less active than it is in children. It is most often done on an outpatient basis under general anesthesia. Post-operative pain is generally minimal and reduced by icy or cold foods. The procedure is often combined with tonsillectomy, for which the recovery time is an estimated 10–14 days, sometimes longer, mostly dependent on age.

<span class="mw-page-title-main">Tonsillitis</span> Inflammation of the tonsils

Tonsillitis is inflammation of the tonsils in the upper part of the throat. It can be acute or chronic. Acute tonsillitis typically has a rapid onset. Symptoms may include sore throat, fever, enlargement of the tonsils, trouble swallowing, and enlarged lymph nodes around the neck. Complications include peritonsillar abscess (Quinsy).

<span class="mw-page-title-main">Tonsil stones</span> Mineralized debris within the crevices of the tonsils

Tonsil stones, also known as tonsilloliths, are mineralizations of debris within the crevices of the tonsils. When not mineralized, the presence of debris is known as chronic caseous tonsillitis (CCT). Symptoms may include bad breath, foreign body sensation, sore throat, pain or discomfort with swallowing, and cough. Generally there is no pain, though there may be the feeling of something present. The presence of tonsil stones may be otherwise undetectable, however some people have reported seeing white material in the rear of their throat.

<span class="mw-page-title-main">Lingual tonsils</span> Lymphatic tissue in the tongue

The lingual tonsils are a collection of lymphatic tissue located in the lamina propria of the root of the tongue. This lymphatic tissue consists of the lymphatic nodules rich in cells of the immune system (immunocytes). The immunocytes initiate the immune response when the lingual tonsils get in contact with invading microorganisms.

<span class="mw-page-title-main">Keratosis pharyngis</span> Medical condition

Keratosis Pharyngis is a medical condition where keratin grows on the surface of the pharynx, that is the part of the throat at the back of the mouth. Keratin is a protein that normally occurs as the main component of hair and nails. It is characterized by the presence of whitish-yellow dots on the pharyngeal wall, tonsils or lingual tonsils. They are firmly adherent and cannot be wiped off. The surrounding region does not show any sign or inflammation or any other symptoms that make affect the rest of the body.

<span class="mw-page-title-main">Head and neck anatomy</span>

This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.

<span class="mw-page-title-main">Waldeyer's tonsillar ring</span> A ringed arrangement of lymphoid tissue in the pharynx

Waldeyer's tonsillar ring is a ringed arrangement of lymphoid organs in the pharynx. Waldeyer's ring surrounds the naso- and oropharynx, with some of its tonsillar tissue located above and some below the soft palate.

<span class="mw-page-title-main">Tonsil</span> Lymphoid organs in the mouth and throat

The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play an important role in the immune system.

<span class="mw-page-title-main">Adenoiditis</span> Medical condition

Adenoiditis is the inflammation of the adenoid tissue usually caused by an infection. Adenoiditis is treated using medication or surgical intervention.

Chronic systemic inflammation (SI) is the result of release of pro-inflammatory cytokines from immune-related cells and the chronic activation of the innate immune system. It can contribute to the development or progression of certain conditions such as cardiovascular disease, cancer, diabetes mellitus, chronic kidney disease, non-alcoholic fatty liver disease, autoimmune and neurodegenerative disorders, and coronary heart disease.

<span class="mw-page-title-main">Pharynx</span> Part of the throat that is behind the mouth and nasal cavity

The pharynx is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea. It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food to the esophagus and air to the larynx. The flap of cartilage called the epiglottis stops food from entering the larynx.

<span class="mw-page-title-main">Tonsillar crypts</span> Deep indentations in human tonsils

The human palatine tonsils (PT) are covered by stratified squamous epithelium that extends into deep and partly branched tonsillar crypts, of which there are about 10 to 30. The crypts greatly increase the contact surface between environmental influences and lymphoid tissue. In an average adult palatine tonsil the estimated epithelial surface area of the crypts is 295 cm2, in addition to the 45 cm2 of epithelium covering the oropharyngeal surface.

Neuroinflammation is inflammation of the nervous tissue. It may be initiated in response to a variety of cues, including infection, traumatic brain injury, toxic metabolites, or autoimmunity. In the central nervous system (CNS), including the brain and spinal cord, microglia are the resident innate immune cells that are activated in response to these cues. The CNS is typically an immunologically privileged site because peripheral immune cells are generally blocked by the blood–brain barrier (BBB), a specialized structure composed of astrocytes and endothelial cells. However, circulating peripheral immune cells may surpass a compromised BBB and encounter neurons and glial cells expressing major histocompatibility complex molecules, perpetuating the immune response. Although the response is initiated to protect the central nervous system from the infectious agent, the effect may be toxic and widespread inflammation as well as further migration of leukocytes through the blood–brain barrier may occur.

<span class="mw-page-title-main">Coblation tonsillectomy</span>

Coblation tonsillectomy is a surgical procedure in which the patient's tonsils are removed by destroying the surrounding tissues that attach them to the pharynx. It was first implemented in 2001. The word coblation is short for ‘controlled ablation’, which means a controlled procedure used to destroy soft tissue.

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