Medical terms A–Z

An organ that does most of its work before adulthood and then fades, having already trained the immune cells a person keeps for life.

A form of thyroid-stimulating hormone (TSH) that is made in the laboratory.

The scaffold protein on which thyroid hormone is assembled and stored, and the blood marker used to watch for returning thyroid cancer.

A gland located beneath the larynx (voice box) that makes thyroid hormone and calcitonin.

Subtype governs almost everything about the outlook, so two people given the same diagnosis on paper can face very different diseases.

A type of cell in the thyroid.

A gland located beneath the larynx (voice box) that makes thyroid hormone and calcitonin.

A hormone that affects heart rate, blood pressure, body temperature, and weight.

Treatment with thyroid hormone, which is a hormone that affects heart rate, blood pressure, body temperature, and weight.

A hormone produced by the pituitary gland.

Thyroidectomy removes part or all of the thyroid gland to treat conditions such as nodules, overactive thyroid, or thyroid cancer.

One name covering several unrelated illnesses, united only by an inflamed thyroid and by hormone levels that often swing before settling.

A medical doctor who specializes in thyroid diseases.

A form of thyroid-stimulating hormone (TSH) that is made in the laboratory.

A substance being studied in the treatment of diarrhea caused by infection with Clostridium difficile (a type of bacteria that can grow without oxygen) in cancer patients.

An anticancer drug being studied to stop cell growth.

The tibia is the larger, weight bearing bone of the lower leg, forming the knee joint above and the ankle joint below.

A monoclonal antibody being studied in the treatment of melanoma and some other types of cancer.

A measure of time after a disease is diagnosed (or treated) until the disease starts to get worse.

An anticancer drug that is also used in cancer prevention.

Tinidazole is an antiprotozoal drug for infections such as giardiasis and trichomoniasis, with an investigational role in certain stomach infections still being studied.

Most tinnitus is generated inside the hearing pathways of the brain rather than by the ear, which is why quiet rooms make it louder.

A drug that is used with another drug, warfarin, to treat blood clots that form deep in the veins and to prevent new blood clots from forming.

A drug that is used with another drug, warfarin, to treat blood clots that form deep in the veins and to prevent new blood clots from forming.

A substance that is being studied in the treatment of acute myeloid leukemia (AML) and other types of cancer.

A drug used with another drug, ritonavir, to treat patients who are infected with HIV (the virus that causes AIDS) and have been treated with other anti-HIV drugs.

A drug that makes tumor cells more sensitive to radiation therapy.

Tissue is a group of similar cells and their surrounding material organized together to carry out a shared function within the body.

A type of breast reconstruction in which a flap of tissue is surgically moved from another area of the body to the chest, and formed into a new breast mound.

The body's own clot-dissolving switch, copied in the laboratory to become the drug given to reopen a blocked artery during a stroke.

A laboratory-made copy of a milk protein, promoted against kidney and lung cancer until the late trials came back negative.

A substance that is being studied in the treatment of cancer.

Distinctive less for what happens during practice than for how tightly the method and the teaching of it are standardized.

A substance being studied in the treatment of some types of cancer.

TNF related apoptosis inducing ligand, or TRAIL, is a natural immune protein that triggers programmed cell death in certain abnormal or infected cells.

A gene therapy product that is being studied in combination with radiation therapy in the treatment of cancer.

A substance being studied in the treatment of cancer.

A plant with leaves that have high levels of the addictive chemical nicotine.

A substance that has been studied as an anticancer drug.

Toluene is a strong smelling industrial solvent whose vapors are toxic to the nervous system and other organs with significant exposure.

Tomography is the general technique of producing cross sectional images of the body's interior, applied across several different imaging technologies.

A type of therapy in which radiation is aimed at a tumor from many different directions.

Tonga is an alternate name for kava, a South Pacific plant whose root preparation is used traditionally for its calming and sedative effects.

Tongue cancer arises from tissue of the tongue and is classified as an oral cavity or throat cancer depending on the part affected.

Tonsil most often refers to the palatine tonsils, paired lymphoid masses at the back of the mouth that help screen inhaled and swallowed material.

White patches on inflamed tonsils are widely read as proof of a bacterial cause, though viruses produce them just as readily.

A topical medication is applied directly to the skin or another body surface to act at that location rather than throughout the body.

Treatment with anticancer drugs in a lotion or cream applied to the skin.

A substance that blocks topoisomerases (enzymes that break and rejoin DNA strands and are needed for cells to divide and grow).

A drug used to treat testicular and small cell lung cancers.

A chemotherapy drug that jams the enzyme cells rely on to untangle DNA while they are copying it.

A drug used to treat certain types of ovarian cancer, lung cancer, and cervical cancer.

A close chemical relative of tamoxifen, differing by a single chlorine atom, prescribed for advanced hormone-sensitive breast cancer.

A drug used to treat advanced renal cell carcinoma (a type of kidney cancer).

The gain is not the robot but the route: reaching the throat through the mouth avoids splitting the jaw to get there.

A monoclonal antibody that is used in the treatment of certain types of non-Hodgkin lymphoma.

Therapy used to eliminate male sex hormones (androgens) in the body.

Therapy used to eliminate estrogen in the body.

The commonest misunderstanding in gynecology: total means the cervix as well, not the ovaries as well.

An operation to remove all of the larynx (voice box).

Removal of the breast.

Radiation therapy to the mantle field, the spleen, the lymph nodes in the upper abdomen, and the lymph nodes in the pelvic area.

Surgery to remove the entire pancreas.

The total amount of prostate-specific antigen (PSA) in the blood.

A type of radiation therapy using electrons that is directed at the entire surface of the body.

Radiation therapy to the entire body.

A drug used to treat the toxic effects of an anticancer drug that leaks from a vein into surrounding tissue and causes tissue damage.

Having to do with cells that are able to develop into any type of cell found in the body.

A tourniquet is a band applied tightly around a limb to restrict blood flow, used for blood draws, surgery, or emergency bleeding control.

Disease caused by the spread of bacteria and their toxins in the bloodstream.

Toxic describes a substance capable of causing harm to the body, with the likelihood and severity of harm depending largely on the amount involved.

Toxicity describes how harmful a substance is to the body, a property that depends heavily on dose, exposure, and the tissue affected.

Toxicology examines how chemicals and other substances harm the body, guiding the diagnosis and management of poisoning cases.

A poison made by certain bacteria, plants, or animals, including insects.

The body's own clot dissolving switch, borrowed as a drug because it works hardest exactly where a clot has formed.

The word total is the whole point: nothing is expected of the gut, so every nutrient has to be in the bag.

TPO most often names thrombopoietin, the hormone driving platelet production, though the same abbreviation also names an unrelated thyroid enzyme.

A chemotherapy drug first found in a Caribbean sea squirt, which jams DNA repair rather than simply breaking the strands.

A rare type of cancer that forms on or just beneath the skin, usually in parts of the body that have been exposed to the sun.

An element found in very small amounts in a given substance.

A substance given in a quantity too small to have any effect, chosen purely so its movement through the body can be watched.

A 2-inch- to 3-inch-long curved metal or plastic tube placed in a surgically created opening (tracheostomy) in the windpipe to keep it open.

The trachea is the airway connecting the larynx to the bronchi, held open by rings of cartilage that keep it from collapsing.

A landmark as much as a structure: tube depth, biopsy sites and staging in the chest are all reckoned from this one ridge.

Surgery to remove the cervix (the end of the uterus that forms a canal between the uterus and the vagina).The upper part of the vagina and certain pelvic lymph nodes may also be removed.

A small opening made by a surgeon between the esophagus and the trachea.

A tracheostomy provides an airway route that bypasses the mouth, nose, and throat entirely, distinguishing it from a tube passed through those structures.

A 0.5-inch- to 1.5-inch-long plastic tube placed in a surgically created opening (tracheostomy) in the windpipe to keep it open.

Breathing through an opening in the neck rather than the nose and mouth, with the voice box left out of the path.

Tradition describes a belief or practice about health passed down within a family, culture, or community, shaping how a person understands and responds to illness.

An ancient form of acupuncture based on the principle that there are five universal elements (wood, fire, earth, metal, and water) that affect a person's emotions, personality, health, and response…

A protein on the surface of certain cells that binds another protein called TRAIL, which may kill some cancer cells.

A protein on the surface of certain cells that binds another protein called TRAIL, which may kill some cancer cells.

A protein on the surface of certain cells that binds another protein called TRAIL, which may kill some cancer cells.

An opioid painkiller with a second action on brain chemistry, which accounts for both its usefulness and its unusual risks.

Tranquilizer is an older term for medications that calm anxiety or induce sedation, now mostly replaced clinically by more specific drug class names.

A type of fat that has certain chemical properties and is usually found in processed foods such as baked goods, snack foods, fried foods, shortening, margarine, and certain vegetable oils.

The everyday scan done with a probe on the belly wall, trading fine detail for a wide view and no radiation at all.

A mental technique used to promote relaxation, reduce stress, and improve quality of life.

Copying a gene into RNA is the step where a cell decides which of its instructions to act on and how loudly.