Thyroid Terms and Abbreviations
The following are some of the Thyroid Health and Medical Definitions of Terms that appear throughout this web site
Abdominal: Relating to the abdomen, the belly, that part of the body that contains all of the structures between the chest and the pelvis. The abdomen is separated anatomically from the chest by the diaphragm, the powerful muscle spanning the body cavity below the lungs.
Abdominal pain:Pain in the belly (the abdomen). Abdominal pain can come from conditions affecting a variety of organs. The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone (pubic ramus) below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity (the skin and abdominal wall muscles), the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity (from beneath the skin and muscles). These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas.
Abnormal: Not normal. Deviating from the usual structure, position, condition, or behaviour. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer).
Abruption: A sudden breaking off or away. Abruption of the placenta (abruptio placentae) is the premature separation of the placenta from the wall of the uterus, a potentially very serious situation for the mother and baby.
Adam’s apple: A familiar anatomic feature in the front of the neck that is due to the forward protrusion of the thyroid cartilage, the largest and most prominent cartilage of the larynx.
Adenoma: A benign tumor that arises in or resembles glandular tissue. If it becomes cancerous, it is called an adenocarcinoma.
Aneamia: The condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased.
Angina Chest pain due to an inadequate supply of oxygen to the heart muscle. The chest pain of angina is typically severe and crushing. There is a feeling just behind the breastbone (the sternum) of pressure and suffocation.
Antibody: An immunoglobulin, a specialized immune protein, produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production.
Antithyroid antibody: An antibody directed against the thyroid gland, a gland which produces thyroid hormones (such as, for example, thyroxine and triiodothyronine). Antithyroid antibodies can be associated with inflammation of the thyroid gland and affect its function. Antithyroglobulin and antimicrosomal antibodies are examples of antithyroid antibodies.
Antithyroid drug: A drug directed against the thyroid gland. The antithyroid drugs include carbimazole, methimazole, and propylthiouracil (PTU). These drugs are used to treat hyperthyroidism (overactivity of the thyroid gland) in order to reduce the excessive thyroid activity before surgery and to treat and maintain patients not having surgery.
Arthritis: Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis (osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, lupus, gout, pseudogout)
Aspiration: Removal of a sample of fluid and cells through a needle. Aspiration also refers to the accidental sucking in of food particles or fluids into the lungs.
Autoimmune: Pertaining to autoimmunity, a misdirected immune response that occurs when the immune system goes awry and attacks the body itself.
Benign: Not cancer. Not malignant. A benign tumor does not invade surrounding tissue or spread to other parts of the body. A benign tumor may grow but it stays put (in the same place).
Beta blocker: A class of drugs that block beta-adrenergic substances such as adrenaline (epinephrine) in the sympathetic portion of the autonomic (involuntary) nervous system. By blocking the action of the sympathetic nervous system on the heart, beta blockers relieve stress on the heart; they slow the heart beat, lessen the force with which the heart muscle contracts, and reduce blood vessel contraction in the heart, brain, and throughout the body. Beta blockers may be used to treat abnormal heart rhythms (cardiac arrhythmias) and prevent abnormally fast heart rates (tachycardias) or irregular heart rhythms such as premature ventricular beats. Since beta blockers reduce the demand of the heart muscle for oxygen and the chest pain of angina pectoris occurs when the oxygen demand of the heart exceeds the supply, beta blockers can be useful in treating angina. They have also become an important drug in improving survival after a person has had a heart attack. Thanks to their effect on blood vessels, beta blockers can lower the blood pressure and be of value in the treatment of hypertension. Other uses for beta blockers include the prevention of migraine headaches and the treatment of certain types of tremors (familial or hereditary essential tremors).
Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It’s measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".
Bowel: Another name for the intestine. The small bowel and the large bowel are the small intestine and large intestine, respectively.
Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called “hemispheres”.
Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction, and then exhaled due to muscle relaxation.
Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
Carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs. For example, carcinoma can arise in the breast, colon, liver, lung, prostate, and stomach.
Cardiac: Having to do with the heart.
Carpal tunnel syndrome: A type of compression neuropathy (nerve damage) caused by compression and irritation of the median nerve in the wrist. The nerve is compressed within the carpal tunnel, a bony canal in the palm side of the wrist that provides passage for the median nerve to the hand. The irritation of the median nerve is specifically due to pressure from the transverse carpal ligament.
Cartilage: Firm, rubbery tissue that cushions bones at joints. A more flexible kind of cartilage connects muscles with bones and makes up other parts of the body, such as the larynx and the outside parts of the ears.
Cell:The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane.
Chest: The area of the body located between the neck and the abdomen. The chest contains the lungs, the heart and part of the aorta. The walls of the chest are supported by the dorsal vertebrae, the ribs, and the sternum.
Chest pain: There are many causes of chest pain. One is angina which results from inadequate oxygen supply to the heart muscle. Angina can be caused by coronary artery disease or spasm of the coronary arteries. Chest pain can also be due to a heart attack (coronary occlusion) and other important diseases such as, for example, dissection of the aorta and a pulmonary embolism. Do not try to ignore chest pain and "work (or play) though it." Chest pain is a warning to seek medical attention.
Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
Coma: A state of deep unarousable unconsciousness.
Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of congenital in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
Constipation: Infrequent (and frequently incomplete) bowel movements. The opposite of diarrhoea, constipation is commonly caused by irritable bowel syndrome, diverticulosis, and medications (constipation can paradoxically be caused by overuse of laxatives). Colon cancer can narrow the colon and thereby cause constipation. The large bowel (colon) can be visualized by barium enema x-rays, sigmoidoscopy, and colonoscopy. Barring a condition such as cancer, high-fiber diets can frequently relieve the constipation.
Corticosteroid: Any of the steroid hormones made by the cortex (outer layer) of the adrenal gland. Cortisol is a corticosteroid.
Cough: A rapid expulsion of air from the lungs typically in order to clear the lung airways of fluids, mucus, or material. Also called tussis.
CT scan: Computerized tomography scan. Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them into pictures on a screen. CT stands for computerized tomography.
Depression:An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely”pull themselves together”and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
Diabetes: Refers to diabetes mellitus or, less often, to diabetes insipidus. Diabetes mellitus and diabetes insipidus share the name “diabetes” because they are both conditions characterized by excessive urination (polyuria).
Diagnosis: 1The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV.
Dizziness: Painless head discomfort with many possible causes including disturbances of vision, the brain, balance (vestibular) system of the inner ear, and gastrointestinal system. Dizziness is a medically indistinct term which laypersons use to describe a variety of conditions ranging from lightheadedness, unsteadiness to vertigo.
Dry skin: Abnormally dry skin. Can be caused by a dry climate, winter weather, deficiency of vitamin A, systemic illness, overexposure to sunlight, or medication. The skin loses moisture. It may crack and peel. Or it may become irritated, inflamed, and itch. Bathing frequently, especially with soaps, can contribute to dry skin.
Dysfunction: Difficult function or abnormal function.
Eclampsia: Convulsions (seizures) occurring with pregnancy-associated high blood pressure and having no other cause.
Emergency department: The department of a hospital responsible for the provision of medical and surgical care to patients arriving at the hospital in need of immediate care. Emergency department personnel may also respond to certain situations within the hospital such cardiac arrests.
Eskalith: See: Lithium.
Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.
Foetus: The unborn offspring from the end of the 8thweek after conception (when the major structures have formed) until birth. Up until the eighth week, the developing offspring is called an embryo.
Fever: Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.).
Gland:1. A group of cells that secrete a substance for use in the body. For example, the thyroid gland. 2. A group of cells that removes materials from the circulation. For example, a lymph gland.
Goitre:Enlargement of the thyroid gland.
Hair loss: Hair loss is the thinning of hair on the scalp. The medical term for hair loss is alopecia. Alopecia can be temporary or permanent. The most common form of hair loss occurs gradually and is referred to as "androgenetic alopecia," meaning that a combination of hormones (androgens are male hormones) and heredity (genetics) is needed to develop the condition. Other types of hair loss include alopecia areata (patches of baldness that usually grow back), telogen effluvium (rapid shedding after childbirth, fever, or sudden weight loss); and traction alopecia (thinning from tight braids or ponytails).
Hashimoto thyroiditis: A progressive disease of the thyroid gland characterized by the presence of antibodies directed against the thyroid, and by infiltration of the thyroid gland by lymphocytes. Hashimoto thyroiditis is the most common cause of hypothyroidism in North America and Europe. In this condition, the thyroid gland is usually enlarged (goiter) and has a decreased ability to make thyroid hormones. Hashimoto disease predominantly affects women, and can be inherited. It is also known as autoimmune thyroiditis and Hashimoto disease.
Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels. Among the many types of heart disease, see, for example: Angina; Arrhythmia; Congenital heart disease; Coronary artery disease (CAD); Dilated cardiomyopathy; heart attack (myocardial infarction); Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse and Pulmonary stenosis.
Heart failure: Inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver and kidneys. Heart failure may be due to failure of the right or left or both ventricles. The signs and symptoms depend upon which side of the heart is failing. They can include shortness of breath (dyspnea), asthma due to the heart (cardiac asthma), pooling of blood (stasis) in the general body (systemic) circulation or in the liver’s (portal) circulation, swelling (edema), blueness or duskiness (cyanosis), and enlargement (hypertrophy) of the heart.
Heart rate: The number of heart beats per unit time, usually per minute. The heart rate is based on the number of contractions of the ventricles (the lower chambers of the heart). The heart rate may be too fast (tachycardia) or too slow (bradicardia). The pulse is a bulge of an artery from the wave of blood coursing through the blood vessel as a result of the heart beat. The pulse is often taken at the wrist to estimate the heart rate.
Hepatitis: Inflammation of the liver from any cause.
Herbal: 1.An adjective, referring to herbs, as in an herbal tea.
2. A noun, usually reflecting the botanical or medicinal aspects of herbs; also a book which catalogs and illustrates herbs.
Hoarseness: a term referring to abnormal voice changes. Hoarseness may be manifested as a voice that sounds breathy, strained, rough, raspy, or a voice that has higher or lower pitch. There are many causes of hoarseness, including viral laryngitis, vocal cord nodules, laryngeal papillomas, gastroesophageal reflux-related laryngitis, and environmental irritants (such as tobacco smoking) An accumulation of fluid in the vocal cords associated with hoarseness has been termed Reinke’s oedema. Reinke’s edema may occur as a result of cigarette smoking or voice abuse (prolonged or extended talking or shouting). Rarely, hoarseness results from serious conditions such as cancers of the head and neck region.
Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
Hyperthyroid: Excess of thyroid hormone resulting from an overactive thyroid gland (or taking too much thyroid hormone). Symptoms can include increased heart rate, weight loss, depression, and cognitive slowing. Treatment is by medication, the use of radioactive iodine, thyroid surgery, or reducing the dose of thyroid hormone.
Hypothalamus:The area of the brain that controls body temperature, hunger, and thirst.
Hypothyroid: Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck:
Immunoglobulin: A protein produced by plasma cells and lymphocytes and characteristic of these types of cells. Immunoglobulins play an essential role in the body’s immune system. They attach to foreign substances, such as bacteria, and assist in destroying them. Immunoglobulin is abbreviated Ig. The classes of immunoglobulins are termed immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin D (IgD) and immunoglobulin E (IgE).
Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.
Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a germ) growing within him, drawing its nourishment from the person.
Inflammation: A basic way in which the body reacts to infection, irritation or other injury, the key feature being redness, warmth, swelling and pain. Inflammation is now recognized as a type of nonspecific immune response.
Insomnia: The perception or complaint of inadequate or poor-quality sleep because of one or more of the following: difficulty falling asleep; waking up frequently during the night with difficulty returning to sleep; waking up too early in the morning; or unrefreshing sleep. Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability.
Intestinal obstruction: Blockage of the intestine by infolding (intussusception), malformation, tumor, digestive problems, a foreign body, or inflammation. Symptoms can include crampy abdominal pain, lack of ability to eliminate normal feces, and eventually shock. On examining the abdomen, the doctor may feel a mass. Abdominal X-rays may suggest intestinal obstruction, but a barium enema may be needed to show the actual cause. Treatment depends on the cause of the obstruction. See also: Intussusception.
Iodide: The chemical form to which iodine in the diet is reduced before it is absorbed through the intestinal wall into the bloodstream and carried through the blood to the thyroid gland.
Iodine: An essential element in the diet used by the thyroid gland to make thyroid hormones.
Iodine deficiency: Iodine is a natural requirement of our diets. Iodine deficiency can lead to inadequate production of thyroid hormone from the thyroid gland (hypothyroidism) For example, in some parts of Zaire, Ecuador, India, and Chile, remote, mountainous areas, such as in the Alps (in the past), Andes and the Himalayas have a particular predisposition to severe iodine deficiency, goiter, and hypothyroidism. Since the addition of iodine to table salt, iodine deficiency is rarely seen in the United States.
Jaundice:Yellow staining of the skin and sclerae (the whites of the eyes) by abnormally high blood levels of the bile pigment bilirubin. The yellowing extends to other tissues and body fluids. Jaundice was once called the “morbus regius”(the regal disease) in the belief that only the touch of a king could cure it.
Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.
Levothyroxine: A synthetic thyroid hormone used as a thyroid hormone replacement drug (brand names include Eltroxin, Levothroid, Levoxine, Levoxyl, Synthroid) used to treat an underactive thyroid gland (hypothyroidism). Because not all brands of levothyroxine sodium are equivalent, it is important not to switch between brand names or even between generic formulations.
Lithium: Lithium carbonate (brand names: Eskalith; Lithobid), a drug used as a mood stabilizer for the treatment of manic/depressive (bipolar) disorder. It prevents or diminishes the intensity of episodes of mania in bipolar patients. Typical symptoms of mania include pressure of speech, motor hyperactivity, reduced need for sleep, flight of ideas, grandiosity, elation, poor judgment, aggressiveness and possibly hostility.
Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.
Lupus: A chronic inflammatory condition caused by an autoimmune disease. An autoimmune disease occurs when the body’s tissues are attacked by its own immune system. Patients with lupus have unusual antibodies in their blood that are targeted against their own body tissues.
Lymph: An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease.
Malignant: 1. Tending to be severe and become progressively worse, as in malignant hypertension. 2. In regard to a tumor, having the properties of a malignancy that can invade and destroy nearby tissue and that may spread (metastasize) to other parts of the body.
Maternal:1. Pertaining to the mother as, for example, the maternal mortality rate. 2. Related through the mother as, for example, the maternal grandparents. 3. Inherited from the mother as, for example, the maternal X chromosome.
Medical history: In clinical medicine, the patient’s past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
Menstrual: Pertaining to menstruation (the menses), as in last menstrual period, menstrual cramps, menstrual cycle, and premenstrual syndrome. From the Latin menstrualis, from mensis meaning month.
Metabolism: The whole range of biochemical processes that occur within an organism. Metabolism consists both of anabolism and catabolism (the buildup and breakdown of substances, respectively). The biochemical reactions are known as metabolic pathways and involve enzymes that transform one substance into another substance, either breaking down a substance or building a new chemical substance. The term is commonly used to refer specifically to the breakdown of food and its transformation into energy.
Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.
Miscarriage: Inadvertent loss of a pregnancy before the fetus is viable. A considerable proportion of pregnancies end in a miscarriage. Also called a spontaneous abortion.
Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.
Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called “skeletal muscle” Heart muscle is called “cardiac muscle.” Muscle that is in the walls of arteries and bowel is called “smooth muscle.”
Nausea: Nausea, is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza, medications, pain, and inner ear disease. When nausea and/or vomiting are persistent, or when they are accompanied by other severe symptoms such as abdominal pain, jaundice, fever, or bleeding, a physician should be consulted.
Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.
Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system.
Nodule: A small solid collection of tissue, a nodule is palpable (can be felt). It may range in size from greater than 1.0 cm (3/8 inch) to somewhat less than 2 cm (13/16 inch) in diameter. A nodule may be present in the epidermis, dermis or subcutis (at any level in the skin).
Nuclear medicine: The branch of medicine concerned with the use of radioisotopes in the diagnosis, management, and treatment of disease. Nuclear medicine uses small amounts of radioactive materials or radiopharmaceuticals, substances that are attracted to specific organs, bones, or tissues. The radiopharmaceuticals used in nuclear medicine emit gamma rays that can be detected externally by special types of cameras: gamma or PET cameras. These cameras work in conjunction with computers used to form images that provide data and information about the area of body being imaged. The amount of radiation from a nuclear medicine procedure is comparable to that received during a diagnostic x-ray.
Obstruction: Blockage of a passageway. See, for example: airway obstruction’ Intestinal obstruction.
Oesophagus: The tube that connects the pharynx (throat) with the stomach. The oesophagus lies between the trachea (windpipe) and the spine. It passes down the neck, pierces the diaphragm just to the left of the midline, and joins the cardiac (upper) end of the stomach. In an adult, the esophagus is about 25 centimeters (10 inches) long. When a person swallows, the muscular walls of the esophagus contract to push food down into the stomach. Glands in the lining of the esophagus produce mucus, which keeps the passageway moist and facilitates swallowing. Also known as the gullet or swallowing tube. From the Greek oisophagos, from oisein meaning to bear or carry + phagein, to eat.
Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
Pathologist: A doctor who identifies diseases by studying cells and tissues under a microscope.
Pituitary: 1. As an adjective, pertaining to the pituitary gland or its hormonal secretions. 2. As a noun, the pituitary gland itself.
Pituitary adenoma: A benign tumor of the pituitary, the master gland that controls other glands and influences numerous body functions including growth. Although the tumor itself is not cancerous, it may affect pituitary function, and therefore may need to be removed.
Pituitary gland: The main endocrine gland. It is a small structure in the head. It is called the master gland because it produces hormones that control other glands and many body functions including growth. The pituitary consists of the anterior and posterior pituitary.
Placenta: A temporary organ joining the mother and fetus, the placenta transfers oxygen and nutrients from the mother to the fetus, and permits the release of carbon dioxide and waste products from the fetus. It is roughly disk-shaped, and at full term measures about seven inches in diameter and a bit less than two inches thick. The upper surface of the placenta is smooth, while the under surface is rough. The placenta is rich in blood vessels.
Placental: Pertaining to the placenta, the organ joining the mother and featus during pregnancy.
Plexus: 1. In medicine, a network or tangle of lymphatic vessels, nerves, or veins. For example, the brachial plexus is a network of nerves leading to the arm.
Postpartum: In the period just after delivery, as with postpartum depression. Postpartum refers to the mother and postnatal to the baby. From the Latin post, after + partum, birth.
Pregnancy: The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman’s last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long.
Pregnant: The state of carrying a developing fetus within the body.
Prenatal: Occurring or existing before birth.
Prognosis: 1. The expected course of a disease. 2. The patient’s chance of recovery.
The prognosis predicts the outcome of a disease and therefore the future for the patient. His prognosis is grim, for example, while hers is good.
Radiation: 1. Rays of energy. Gamma rays and X-rays are two of the types of energy waves often used in medicine. 2. The use of energy waves to diagnose or treat disease. See also Irradiation.
Radioactive: Emitting energy waves due to decaying atomic nuclei. Radioactive substances are used in medicine as tracers for diagnosis, and in treatment to kill cancerous cells.
Radioactive iodine: An isotope of the chemical element iodine that is radioactive. Radioactive iodine is used in diagnostic tests as well as in radiotherapy of an hyperactive thyroid gland (hyperthyroidism), most often due to Graves’ disease.
Radiotherapy: The treatment of disease with ionizing radiation. Also called radiation therapy.
Rash: Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.
Receptor: 1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors. There is a receptor for (insulin;there is a receptor for low-density lipoproteins (LDL); etc. To take an example, the receptor for substance P, a molecule that acts as a messenger for the sensation of pain, is a unique harbor on the cell surface where substance P docks. Without this receptor, substance P cannot dock and cannot deliver its message of pain. Variant forms of nuclear hormone receptors mediate processes such as cholesterol metabolism and fatty acid production. Some hormone receptors are implicated in diseases such as diabetes and certain types of cancer. A receptor called PXR appears to jump-start the body’s response to unfamiliar chemicals and may be involved in drug-drug interactions.
2. In neurology, a terminal of a sensory nerve that receives and responds to stimuli.
Rheumatoid arthritis: An autoimmune disease which causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Autoimmune diseases occur when the body tissues are mistakenly attacked by its own immune system. The immune system is a complex organization of cells and antibodies designed normally to”seek and destroy” invaders of the body, particularly infections. Patients with these diseases have antibodies in their blood which target their own body tissues, where they can be associated with inflammation. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease. While rheumatoid arthritis is a chronic illness (meaning it can last for years) patients may experience long periods without symptoms.
Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.
Shortness of breath: Difficulty in breathing. Medically referred to as dysponea. Shortness of breath can be caused by respiratory (breathing passages and lungs) or circulatory (heart and blood vessels) conditions. See also dyspnea.
Standard of care: 1. A diagnostic and treatment process that a clinician should follow for a certain type of patient, illness, or clinical circumstance. Adjuvant chemotherapy for lung cancer is “a new standard of care, but not necessarily the only standard of care.” (New England Journal of Medicine, 2004)
Stillbirth: The tragic birth of a dead baby, the delivery of a fetus that has died before birth. There is no possibility of resuscitation. The word”stillbirth”is a fusion of”still” in the now-obsolete sense of “dead” and “birth” = dead birth.
Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a”surgeon”; has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are “minimally invasive”, use scopes, etc.
Surgery: The word “surgery” has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician’s or dentist’s office.
Swallowing tube: Descriptive term for the oesophagus. See: Oesophagus.
Sweating: The act of secreting fluid from the skin by the sweat (sudoriferous) glands. These are small tubular glands situated within and under the skin (in the subcutaneous tissue). They discharge by tiny openings in the surface of the skin.
Symptom: Any subjective evidence of disease. Anxiety, lower back pain, and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.
Symptomatic: 1 With symptoms, as a symptomatic infection. 2 Characteristic, as behaviour symptomatic of Huntington disease. 3 Directed at the symptoms, as symptomatic treatment.
Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.
Synthesis: Putting together different entities to make a whole which is new and different. In biochemistry, synthesis refers specifically to the process of building compounds from more elementary substances by means of one or more chemical reactions.
Tachycardia: A rapid heart rate, usually defined as greater than 100 beats per minute. The tachycardias include sinus tachycardia, paroxysmal atrial tachycardia (PAT), and ventricular tachycardia.
Taste: Taste belongs to our chemical sensing system, or the chemosenses. The complicated process of tasting begins when molecules released by the substances stimulate special cells in the mouth or throat. These special sensory cells transmit messages through nerves to the brain where specific tastes are identified.
Therapeutic: Relating to therapeutics, that part of medicine concerned specifically with the treatment of disease. The therapeutic dose of a drug is the amount needed to treat a disease.
Therapy: The treatment of disease.
Thyroid: 1. The thyroid gland. Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism. 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.)
Thyroid cancer: Cancer of the gland in front of the neck that normally produces thyroid hormone which is important to the normal regulation of the metabolism of the body. There are 4 major types of thyroid cancer == papillary, follicular, medullary, and anaplastic. The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the neck. The only certain way to tell whether a thyroid lump is cancer is by examining the thyroid tissue, obtained using a needle or surgery to obtain a biopsy.
Thyroid cartilage: The largest of the cartilages of the larynx (the voice box).
Thyroid gland: A gland that makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body. Thyroid hormones also help children grow and develop.
Thyroid hormone: A chemical substance made by the thyroid gland for export into the bloodstream. The thyroid gland needs iodine to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3).
Thyroid hormones: Chemical substances made by the thyroid gland, which is located in the front of the neck. This gland uses iodine to make thyroid hormones, which are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism), and are involved in the circadian rhythms that govern sleep, among other essential functions.
Thyroid scan: An image taken of the thyroid gland after radioactive iodine is taken by mouth. The thyroid gland is in front of the neck:
Thyroid storm: Thyroid storm is a severe, life-threatening condition caused by an excess of thyroid hormone. A number of factors can be involved in causing thyroid storm, including over-replacement of thyroid hormones or discontinuing medications taken to treat hyperthyroidism. Symptoms of thyroid storm can include fever (potentially as high as 105-106 degrees F), racing pulse, nausea, vomiting, diarrhoea, irregular heart beat, confusion, and weakness. Thyroid storm may lead to heart failure and requires emergent medical treatment.
Thyroidectomy: The surgical removal of part or all of the thyroid gland.
Thyroiditis: Inflammation of the thyroid gland which is located in front of the neck:
Thyroxine: Abbreviated T4. A hormone made by the thyroid gland that has four iodine molecules attached to its molecular structure. T4 and other thyroid hormones help regulate growth and control the rate of chemical reactions (metabolism) in the body.
Tiredness: See: Tired.
Tomography: The process for generating a tomogram, a two-dimensional image of a slice or section through a three-dimensional object. Tomography achieves this remarkable result by simply moving an x-ray source in one direction as the x-ray film is moved in the opposite direction during the exposure to sharpen structures in the focal plane, while structures in other planes appear blurred. The tomogram is the picture; the tomograph is the apparatus; and tomography is the process.
Toxic multinodular goitre: Condition in which the thyroid gland contains multiple lumps (nodules) that are overactive, produce excess thyroid hormones and thereby cause hyperthyroidism. This condition is also known as Parry’s disease or Plummer’s disease.
Trachea: A tube-like portion of the breathing or “respiratory” tract that connects the “voice box” (larynx) with the bronchial parts of the lungs.
Trauma: Any injury, whether physically or emotionally inflicted. “Trauma” has both a medical and a psychiatric definition. Medically, “trauma” refers to a serious or critical bodily injury, wound, or shock. This definition is often associated with trauma medicine practiced in emergency rooms and represents a popular view of the term. In psychiatry, “trauma” has assumed a different meaning and refers to an experience that is emotionally painful, distressful, or shocking, which often results in lasting mental and physical effects.
Tremor: Any abnormal repetitive shaking movement of the body. Tremors have many causes and can be inherited, be related to illnesses such as thyroid disease, or caused by fever, hypothermia, drugs or fear.
Triiodothyronine: A hormone made by the thyroid gland. It has three iodine molecules attached to its molecular structure. It is the most powerful thyroid hormone, and affects almost every process in the body, including body temperature, growth, and heart rate.
TSH: Stands for thyroid stimulating hormone, a hormone produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain. TSH promotes the growth of the thyroid gland in the neck and stimulates it to produce more thyroid hormones. When there is an excessive amount of thyroid hormones, the pituitary gland stops producing TSH, reducing thyroid hormone production. This mechanism maintains a relatively constant level of thyroid hormones circulating in the blood.
TSH receptor: The receptor for thyroid stimulating hormone (TSH), which is also called thyrotropin. Encoded by a gene on chromosome 14q, TSHR is largest of all known glycoprotein hormone receptors. It is one of the primary antigens in autoimmune thyroid disease. Autoantibodies to TSHR act as TSH agonists in Graves’ disease and as TSH antagonists in Hashimoto thyroiditis.
TSI: Stands for Thyroid Stimulating Immunoglobulin. The TSI level is abnormally high in persons with hyperthyroidism (too much thyroid hormone) due to Graves’ disease. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body.
Tumour: An abnormal mass of tissue. Tumours are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumours. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow. For example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla). Diagnosis depends on the type and location of the tumour. Tumour marker tests and imaging may be used; some tumours can be seen (for example, tumours on the exterior of the skin) or felt (palpated with the hands).
Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.
Vitamins: The word “vitamin” was coined in 1911 by the Warsaw-born biochemist Casimir Funk (1884-1967). At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance “vitamine” because he believed it was necessary to life and it was a chemical amine. The “e” at the end was later removed when it was recognized that vitamins need not be amines.
Voice box: The voice box, or larynx, is the portion of the respiratory (breathing) tract containing the vocal cords which produce sound. It is located between the pharynx and the trachea. The larynx, also called the voice box, is a 2-inch-long, tube-shaped organ in the neck.
Weight loss: Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption (such as from chronic diarrhoeal illness), and chronic inflammation (such as with rheumatoid arthritis).
White blood cell: One of the cells the body makes to help fight infections. There are several types of white blood cells (leukocytes). The two most common types are the lymphocytes and neutrophils (also called polymorphonuclear leukocytes, PMNs, or “polys”).
White blood cell count (leukocyte count): The number of white blood cells (WBCs) in the blood. The WBC is usually measured as part of the CBC (complete blood count). White blood cells are the infection-fighting cells in the blood and are distinct from the red (oxygen-carrying) blood cells known as erythrocytes. There are different types of white blood cells, including neutrophils (polymorphonuclear leukocytes; PMNs), band cells (slightly immature neutrophils), T-type lymphocytes (T cells), B-type lymphocytes (B cells), monocytes, eosinophils, and basophils. All the types of white blood cells are reflected in the white blood cell count. The normal range for the white blood cell count varies between laboratories but is usually between 4,300 and 10,800 cells per cubic millimeter of blood. This can also be referred to as the leukocyte count and can be expressed in international units as 4.3 – 10.8 x 109 cells per litre.