Medical terms A–Z

The gap between too little and too much is narrow, and where food was grown largely decides which side people land on.

Self-esteem reflects a person's overall sense of self-worth, and healthcare providers may address it as part of emotional and psychological wellbeing.

A depression of the bone at the base of the skull where the pituitary gland is located.

A substance that has been studied in the treatment of cancer.

The fluid that is released through the penis during orgasm.

Fluid from the prostate and other sex glands that helps transport sperm out of the man's body during orgasm.

A gland that helps produce semen.

The removal of fluid or tissue with a needle from the seminal vesicles for examination under a microscope.

The slower moving of the two main testicular germ cell tumors, and one of the most curable cancers known.

In botany, a plant that gets food from a host but also contains chlorophyll and is capable of photosynthesis.

An anticancer drug that belongs to the family of drugs called alkylating agents.

A virus being studied in the treatment of neuroendocrine tumors and other types of cancer.

The root of an herb called Polygala senega.

A thick, scaly patch of skin that may become cancer.

A highly sensitive test produces few false negatives, but sensitivity alone does not describe how often a positive result is truly accurate.

Every sensor answers exactly one question, so a reading that looks wrong is as likely to reflect the sensor as the patient.

A drug used to relieve pain by blocking signals at nerve endings.

Sensory nerves and pathways carry information about touch, pain, temperature, and position from the body to the brain for processing.

The node a surgeon samples instead of clearing a whole basin, chosen not for being nearest but for being first in line.

Removal and examination of the sentinel node(s) (the first lymph node(s) to which cancer cells are likely to spread from a primary tumor).

The use of dyes and radioactive substances to identify the first lymph node to which cancer is likely to spread from the primary tumor.

A substance that is being studied as a treatment for cancer.

The presence of bacteria or their toxins in the blood or tissues.

An organ or structure that is divided into compartments.

An older word for bloodstream infection, largely retired because the danger comes from the body's reaction rather than the bacteria alone.

One treatment after the other.

A drug used to treat tuberculosis.

Serosa is the smooth outer covering of many internal organs, formed by the same tissue that lines the chest and abdominal cavities.

The brain and gut supplies are separate, because the molecule cannot cross from blood into brain tissue, and each pool works on its own.

Serous describes thin, watery fluid or the membranes that produce it, distinguishing it from thicker mucous secretions elsewhere in the body.

A serous membrane lines internal body cavities and covers the organs within them, secreting fluid that reduces friction during movement.

A rare type of ovarian tumor in which the tumor cells secrete a male sex hormone.

The block on reuptake happens within hours, yet the change in mood takes weeks, and that gap is still not fully explained.

Serum is the clear fluid left after blood clots, containing proteins, hormones, and other dissolved substances but no cells or clotting factors.

The most abundant protein in blood, and a number that tracks how ill someone is far more reliably than how well they eat.

An enzyme found in the liver and other tissues.

An enzyme found in the liver, heart, and other tissues.

A blood test that measures the amount of substances called tumor markers (or biomarkers).

A drug used to treat depression.

A substance found in some plants.

A type of breast imaging test that is used to detect cancer cells in the breasts of some women who have had abnormal mammograms, or who have dense breast tissue.

An imaging test used to find overactive parathyroid glands (four pea-sized glands found on the thyroid) and breast cancer cells, and to diagnose heart disease.

A severe form of myelosuppression.

A rare type of cancer that forms in the tissues that support the ovaries or testes.

A rare type of cancer that forms in the tissues that support the ovaries or testes.

A rare type of cancer that forms in the tissues that support the ovaries or testes.

Sex drive is the everyday term for libido, a person's level of motivation or desire for sexual activity.

Sexual drive describes a person's motivation or desire for sexual activity, which can vary widely and change over time.

Illness, surgery, medication and aging all reach this part of life, which is why care teams raise it alongside other quality of life concerns.

The blood is what sets it apart: the same malignant cells circulate, so it behaves unlike a lymphoma confined to skin.

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

A monoclonal antibody that binds to cells that have the CD30 antigen on their surface, including Hodgkin disease cells and cells from anaplastic large cell lymphoma, and cutaneous T-cell lymphoma.

A monoclonal antibody that binds to cells that have the CD40 antigen on their surface, including cells from multiple myeloma, non-Hodgkin lymphoma, and chronic lymphocytic leukemia.

An inactive treatment or procedure that is intended to mimic as closely as possible a therapy in a clinical trial.

A procedure in which a skin abnormality and a thin layer of surrounding skin are removed with a small blade for examination under a microscope.

A plant that has been used in some cultures to treat certain medical problems.

A cultivated East Asian mushroom eaten as food and studied in laboratories for a long-chain sugar in its cell walls.

The larger of two bones between the knee and ankle.

A Japanese formulation of seven Chinese herbs that is being studied as a treatment for cancer.

A flat, triangular bone on the upper back, the shoulder blade anchors many of the muscles that stabilize and move the arm.

A shunt is a surgically created pathway that redirects blood or other body fluid from its normal route to another location.

A rare, inherited disorder in which the pancreas and bone marrow do not work the way they should.

An inherited fault in assembling ribosomes that starves the pancreas and the marrow of machinery they need more than most tissues.

Any of a group of simple sugar molecules.

A vaccine composed of a substance that enhances immunity plus an antigen found on some tumors of the colon, breast, lung, ovary, pancreas, and stomach.

An inherited disease in which the red blood cells have an abnormal crescent shape, block small blood vessels, and do not last as long as normal red blood cells.

One letter changed in a hemoglobin gene is enough to stiffen red cells into crescents that jam small vessels and break up early.

A side effect is any effect of a medication, procedure, or other treatment beyond the one it was specifically intended to produce.

A surgical procedure in which the side of the colon is attached to the anus after the rectum has been removed.

A disorder marked by anemia caused by iron deficiency, and a web-like growth of membranes in the throat that makes swallowing difficult.

A conclusion reached only by ruling everything else out, which is why the investigation is so thorough and so painful.

Narrow, muscular and free to swing on its own fold of tissue, this segment collects more than its share of colon problems.

A sigmoidoscope is a lighted, tube shaped instrument used to view and sometimes sample tissue from the rectum and lower colon.

Examination of the lower colon using a sigmoidoscope, inserted into the rectum.

How a message arriving at the cell surface is converted into action inside, growing louder at every step of the relay.

A substance that blocks signals passed from one molecule to another inside a cell.

Relay races rather than single messengers: every handover amplifies the message and gives the cell another point at which it can intervene.

A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease.

A highly malignant type of cancer typically found in glandular cells that line the digestive organs.

A word that promises far less than it sounds like it does: a result unlikely to be chance, not a result that matters.

Found by accident while a heart drug was being tested, it works only where nitric oxide is already being released.

Silicone is a synthetic, chemically stable material used across many medical devices, not only as a breast implant component.

A plant that has been used in some cultures to treat certain medical problems, including stomach, liver, and gallbladder disorders.

A widely sold liver supplement whose one genuinely established use has little to do with the bottle on the shelf.

A virus that infects some types of monkeys.

Removal of the breast.

Surgery to remove one kidney.

Surgery to remove the entire vulva (the external female genital organs, including the clitoris, vaginal lips, and the opening to the vagina).

In radiation therapy, simulation is the planning session that uses imaging to map a patient's anatomy and precisely target the treatment area.

A type of clinical trial in which only the doctor knows whether a patient is taking the standard treatment or the new treatment being tested.

A controller rather than a rescue treatment, and the one common asthma tablet carrying a formal warning about mood and behavior.

A sinus is any hollow cavity or channel within the body, a term applied to structures in the skull, heart, and blood vessels.

Nearly every case starts as an ordinary cold, and the newer name rhinosinusitis records that the nose is inflamed too.

A monoclonal antibody that is being studied in the treatment of certain lymphoproliferative disorders and psoriasis.

A drug used to treat prostate cancer that has spread.

Sirolimus is an immunosuppressant medication used to prevent organ transplant rejection by blocking a key pathway that drives immune cell growth.

SIRS describes a whole body inflammatory response identified through vital sign and blood count changes, seen with infection or with noninfectious injury.

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

A substance being studied in the treatment of certain multiple myelomas and other advanced cancers.

An adjective doing heavy lifting in reports: it can mean bone, or muscle attached to bone, depending on the noun.