What Are Human Tonsils and What Do They Do?

Tonsils are lumps of immune tissue at the back of the mouth and nose that check germs and food particles as they enter the body. They’re most active in childhood, and the body copes without them because other tissue carries on the same work.1PubMed Central. Effects of tonsillectomy and adenoidectomy on the immune system In evolutionary terms they’re a recent invention, found in modern mammals but missing in some animals, such as rats.2PubMed Central. The Tonsils Revisited: Review of the Anatomical Localization and Histological Characteristics of the Tonsils of Domestic and Laboratory Animals

Where Your Tonsils Are

Most people picture the two lumps at the sides of the throat, but there are four kinds of tonsil.3PubMed Central. Anatomy and physiology of the palatine tonsils, adenoids, and lingual tonsils Together they form a broken ring of immune tissue circling the top of the throat and back of the nose.4PubMed Central. Anatomy and physiology of the palatine tonsils, adenoids, and lingual tonsils5PubMed. Mapping Human Immunity and the Education of Waldeyer’s Ring The spot matters because air and food both enter there, so everything you breathe or swallow passes by them.6PubMed Central. Anatomy and physiology of the palatine tonsils, adenoids, and lingual tonsils

Only the palatine tonsils show when you open wide, say “ah,” and shine a light in. The adenoids can’t be seen without a small mirror or a camera.

The palatine tonsils are the ones that visibly swell with a sore throat. Adenoids can be enlarged for a long time without anyone seeing a thing. The clues are indirect: a blocked nose, mouth breathing, or a muffled, stuffed-up voice. Because the adenoids sit near the openings of the ear tubes, along with the tubal tonsils, they can be part of why some children have ear trouble along with throat trouble, and the two complaints are often looked at together.

A tonsillectomy removes the palatine tonsils only. Adenoids come out in a separate operation, often done at the same time. The rest of the ring stays in place.

What Tonsils Do for Your Immune System

The tonsil surface dips into deep pits, which greatly increase the area exposed to the mouth. The lining of these pits is a loose mesh of cells with gaps packed with immune cells.11Romanian Journal of Morphology and Embryology. Ultrastructure of the human palatine tonsil and its functional significance Tiny blood vessels run right up into this lining, so immune cells can arrive and leave quickly.12Romanian Journal of Morphology and Embryology. Ultrastructure of the human palatine tonsil and its functional significance

Deeper inside, a tonsil works much like a lymph node. It contains training centers where B cells, which make antibodies, multiply and learn to target what was sampled.13PubMed Central. Toll-like receptors in cellular subsets of human tonsil T cells: altered expression during recurrent tonsillitis Helper T cells sit in these centers and guide the B cells as they mature.14PubMed Central. Toll-like receptors in cellular subsets of human tonsil T cells: altered expression during recurrent tonsillitis Tonsil cells also carry sensors that recognize common features of bacteria and viruses.15PubMed Central. Toll-like receptors in cellular subsets of human tonsil T cells: altered expression during recurrent tonsillitis

Lymph nodes in the neck hold similar immune cells, but the two sit in different places. Tonsils are on the surface where germs arrive, while nodes sit along the drainage routes behind them. That’s why swollen neck glands often show up alongside sore tonsils.

A key product of all this is IgA, an antibody designed to be carried onto moist surfaces like the throat and nose.16International Congress Series. Immunology of tonsils and adenoids: everything the ENT surgeon needs to know It can coat germs before they attach to the lining.

Tonsils don’t filter out every germ. They let germs in on purpose, to show them to the immune system, and that sampling is also why the tonsils sometimes become infected themselves.

A tonsil fighting an infection can look red and swollen, and may show white or yellow patches, which are debris and immune cells collecting on the surface. The patches alone don’t reveal whether the cause is a virus or bacteria, since both can produce them. A throat swab test tells the two apart, and that matters because only bacterial infections like strep respond to antibiotics. Most sore throats with swollen tonsils are viral and pass on their own, so the swelling is a sign the tonsils are doing their job rather than failing.

How Tonsils Change From Childhood to Adulthood

Between about 6 and 20, adenoids and tonsils take up a steadily smaller share of the airway.17PubMed Central. Differential changes in the adenoids and tonsils in Japanese children and teenagers: a cross-sectional study The change is gradual, not the sudden spike and drop around puberty that older textbooks described.18PubMed Central. Patterns of adenoid and tonsil growth in Japanese children and adolescents: A longitudinal study Adenoids and tonsils also follow different growth patterns from each other.19PubMed Central. Differential changes in the adenoids and tonsils in Japanese children and teenagers: a cross-sectional study

Activity changes too. Children’s tonsils before puberty have far more active training centers than teenagers’ or adults’ tonsils.20PubMed Central. Role of germinal center and CD39highCD73+ B cells in the age-related tonsillar involution Older tonsils hold more memory cells that recall germs already met.21PubMed Central. Role of germinal center and CD39highCD73+ B cells in the age-related tonsillar involution

Big tonsils in a small throat are expected in young children, and size alone doesn’t mean infection. They usually look biggest relative to the throat in the early school years. The throat then grows around them, so they appear to shrink even if they change little in absolute size. A child can have large tonsils, no symptoms, and no need for any treatment. The question for doctors is whether the size causes trouble, such as disturbed sleep or trouble swallowing.

Adult tonsils still work, but they’ve done much of their training. One tonsil that is noticeably larger than the other in an adult is worth showing to a doctor.

Why Tonsils Swell or Keep Getting Infected

Bacteria in the tonsil pits can form sticky, protected communities called biofilms.22PubMed Central. Evidence of Bacterial Biofilms among Infected and Hypertrophied Tonsils in Correlation with the Microbiology, Histopathology, and Clinical Symptoms of Tonsillar Diseases Biofilms were found in 60% of people having tonsils removed for infection or enlargement.23PubMed Central. Evidence of Bacterial Biofilms among Infected and Hypertrophied Tonsils in Correlation with the Microbiology, Histopathology, and Clinical Symptoms of Tonsillar Diseases Staphylococcus aureus in chronically infected tonsils very often forms strong biofilms,24PubMed Central. Analysis of Tonsil Tissues from Patients Diagnosed with Chronic Tonsillitis—Microbiological Profile, Biofilm-Forming Capacity and Histology so antibiotics can fail to clear them, helping infections return.25PubMed Central. Analysis of Tonsil Tissues from Patients Diagnosed with Chronic Tonsillitis—Microbiological Profile, Biofilm-Forming Capacity and Histology Recurrent tonsillitis also goes with a shift in the mix of bacteria living in the pits.26PubMed Central. Molecular Mapping to Species Level of the Tonsillar Crypt Microbiota Associated with Health and Recurrent Tonsillitis

When survivors regrow after antibiotics, the sore throat returns, and it may be the same stubborn colony. This is one reason doctors consider surgery for repeated infections that keep coming back despite proper treatment, rather than just prescribing more antibiotics.

A single bad tonsil infection is common and usually doesn’t call for surgery, since most clear up on their own or with treatment. Doctors look at the pattern: how many infections occur in a year, how severe they are, and how much school or work they disrupt. They often ask people to keep a record. A collection of pus beside the tonsil (an abscess) points toward something more serious and needs urgent medical attention, unlike ordinary soreness.

Swelling can also block breathing at night. Most cases of sleep apnea in children are linked to enlarged tonsils and adenoids.27Kosin Medical Journal. Treatment of pediatric obstructive sleep apnea Enlarged tonsils raise a child’s sleep apnea risk about threefold, and obesity raises it nearly as much.28PubMed Central. Associations between Adenotonsillar Hypertrophy, Age, and Obesity in Children with Obstructive Sleep Apnea

In a sleeping child, the signs are loud nightly snoring and pauses in breathing, mouth breathing, and restless sleep. Daytime tiredness or changes in behavior can follow. These are reasons to see a doctor rather than wait.

To judge size, doctors usually look in the mouth and grade how much of the throat the tonsils fill. A camera passed through the nose may check the adenoids. Imaging is sometimes used when the visual grade doesn’t match the symptoms.

What Tonsil Stones Are

Tonsil stones form in the tonsil pits and are built like the plaque on teeth.29PubMed. Tonsillolith: not just a stone but a living biofilm Oxygen inside drops to about a tenth of the surrounding level,30PubMed. Tonsillolith: not just a stone but a living biofilm so bacteria that thrive without oxygen grow in the center.31PubMed. Tonsillolith: not just a stone but a living biofilm When sugar reaches a stone, its bacteria produce acid inside.32PubMed. Tonsillolith: not just a stone but a living biofilm These oxygen-free bacteria help explain the bad smell stones often carry.

Stones form in the pits, so people with deeper or more numerous pits trap debris more easily than people with smooth tonsils. Food particles, dead cells and mucus collect there, giving bacteria something to feed on and build around. Because stones depend on the shape of the tonsils, they tend to recur in the same person rather than appearing once.

They usually look different from an infection. Stones are firm, pale specks that come without fever and may cause a mild sense of something stuck, while tonsillitis typically brings pain, fever and red swelling.

Most stones are harmless and fall out alone. Gargling salt water and brushing the tongue can help. Digging at them with sharp objects can injure the tonsil, so it’s best to avoid it. Stones that are frequent or troublesome can be discussed with a doctor.

Can You Live Without Your Tonsils

Antibody levels can drop after tonsil removal.33PubMed Central. Effects of tonsillectomy and adenoidectomy on the immune system34PubMed Central. Long-term impacts of tonsillectomy on children’s immune functions The rest of the ring and throat lining compensate, with IgA rising again within about 3 months of adenoid removal.35PubMed Central. Effects of tonsillectomy and adenoidectomy on the immune system In follow-up of children, immune function recovered to match children who kept their tonsils.36PubMed. Evaluation of long-term impacts of tonsillectomy on immune functions of children: a follow-up study Most children do not become ill more often because of a temporary fall in antibody levels.

Long-term records raise some questions. Among about 1.2 million Danish children, removal in childhood was linked to higher later risk of respiratory, allergic and infectious diseases including asthma.37PubMed Central. Association of Long-Term Risk of Respiratory, Allergic, and Infectious Diseases With Removal of Adenoids and Tonsils in Childhood38The BMJ. Long-term effects of tonsillectomy Those added risks were larger than the change in the problems the surgery aimed to fix.39PubMed Central. Association of Long-Term Risk of Respiratory, Allergic, and Infectious Diseases With Removal of Adenoids and Tonsils in Childhood This shows a link, not proof that surgery caused it. It’s reasonable to ask a surgeon how the expected benefit compares with long-term risks for your child.

Today most removals are for blocked breathing rather than infection,40PubMed. Changes in incidence and indications of tonsillectomy and adenotonsillectomy, 1970-2005 so many surgeons now offer partial removal, which trims the tonsils and leaves some tissue.41PubMed. Factors influencing the indication for tonsillectomy: a historical overview and current concepts Full removal is still preferred for repeated infections or abscesses.42PubMed. Factors influencing the indication for tonsillectomy: a historical overview and current concepts

Adults may react differently, because children’s remaining tissue may compensate better than adults’.43PubMed Central. Effects of tonsillectomy and adenoidectomy on the immune system Adult recovery is usually harder and more painful, and adults should weigh that when deciding.

Tonsils and Throat Cancer

Many tonsil cancers are linked to HPV-16, the virus also behind cervical cancer.44PubMed. HPV integration begins in the tonsillar crypt and leads to the alteration of p16, EGFR and c-myc during tumor formation45PubMed Central. Genital HPVs in the Aerodigestive Tract: Etiologic Association with a Subset of Oropharyngeal/Tonsillar Cancers and with Recurrent Respiratory Papillomatosis The virus settles in the lining of the tonsil pits.46PubMed Central. Genital HPVs in the Aerodigestive Tract: Etiologic Association with a Subset of Oropharyngeal/Tonsillar Cancers and with Recurrent Respiratory Papillomatosis Early changes hidden in the pits are rarely visible,47PubMed Central. Genital HPVs in the Aerodigestive Tract: Etiologic Association with a Subset of Oropharyngeal/Tonsillar Cancers and with Recurrent Respiratory Papillomatosis so these cancers can spread to neck lymph nodes while the tonsil looks normal.48PubMed Central. Genital HPVs in the Aerodigestive Tract: Etiologic Association with a Subset of Oropharyngeal/Tonsillar Cancers and with Recurrent Respiratory Papillomatosis

The first sign may be a lump in the neck from spread to a lymph node, not a sore throat. A neck lump that persists deserves attention even when the throat looks and feels normal.

HPV is a very common virus and most infections clear on their own, so having it does not mean cancer will develop. Cancer appears in a small share of people in whom the infection persists for many years, which is why it often shows up decades after exposure.

Signs worth checking include a painless neck lump lasting more than three weeks, one tonsil getting larger than the other, and a persistent sore throat or ear pain on one side. HPV vaccination lowers the risk of the infection behind these cancers.

Why Researchers Use Donated Tonsils

Removed tonsil tissue can be kept alive and still respond to vaccines and make antibodies.49PubMed Central. Tonsil explants as a human in vitro model to study vaccine responses It has been used to study how a COVID-19 vaccine triggers immunity over two weeks.50PubMed Central. Human tonsil organoids reveal innate pathways modulating humoral and cellular responses to ChAdOx1

It works because tonsil tissue already contains the cells needed for an immune response, including B cells, T cells and the training centers where antibodies are refined. Its structure stays largely intact in a dish, so researchers can watch how the cells interact in a way isolated blood cells don’t allow. A vaccine’s effect can be watched in real human tissue, not only in animals.