Medical terms - Letter I (page 11) | MedicalVocabulary.org

Iodine

An essential element in the diet used by the thyroid gland to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3). Thyroxine (T4) has four iodine molecules…
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…
Iodine excess

Just as too little iodine can cause thyroid disease, so may prolonged intake of too much iodine also lead to the development of goiter (swelling of the thyroid gland) and hypothyroidism (abnormally low thyroid…
Iodine, radioactive

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…
Ion channel

A protein that acts as a pore in a cell membrane and permits the selective passage of ions (such as potassium ions, sodium ions, and calcium ions), by means of which electrical current passes in and out of the cell. Ion…
Iontophoresis

A transdermal delivery system in which a substance bearing a charge is propelled through the skin by a low electrical current. This method can be used to drive a drug across the skin barrier, as is done with pilocarpine…
IOP (intraocular pressure)

The pressure created by the continual renewal of fluids within the eye. The normal IOP varies among individuals. The intraocular pressure is increased in glaucoma. In acute angle-closure glaucoma, the intraocular…
Ipecac

A naturally occurring substance with multiple properties including the ability to cause vomiting (emesis). Ipecac is derived from dried roots of a bush called Uragoga ipecacuanha that is native to Brazil. In the past, a…
Ipsilateral

On the same side. A study of 'ipsilateral breast tumor recurrence following lumpectomy and radiation therapy' pertains to cancer returning in the same breast as has been treated. A lesion in the right side of the brain…
IPT

Interpersonal therapy
IPV

Abbreviation for intelligence quotient, an attempt to measure the intelligence of someone. The IQ score is usually based upon the results of a written test. To calculate the IQ, the person's mental age (as determined by…
IQ

Abbreviation for intelligence quotient, an attempt to measure the intelligence of someone. The IQ score is usually based upon the results of a written test. To calculate the IQ, the person's mental age (as determined by…
IRB

Institutional Review Board
Iressa

Brand name for gefitinib, a drug that attaches to the epidermal growth factor receptor (EGFR) on the surfaces of cells . People with non-small-cell lung cancer who have a mutation in the gene for EGFR enjoy a rapid and…
Iridectomy

The process of making a hole in the iris by surgically removing a full-thickness piece from the iris
Iridectomy, peripheral

See Peripheral iridectomy
Iridology

The practice of diagnosing disease by examining the iris of the eye. Although some diseases do affect the eye, iridology is not considered scientific medicine
Iris

The iris is the circular, colored curtain of the eye. Its opening forms the pupil. The iris helps regulate the amount of light that enters the eye. The eye has a number of other key components. These include the cornea…
Iris melanoma

See: Intraocular melanoma
Iris, speckled

Due to little white (or lightly colored) spots that are slightly elevated on the surface of the iris. These spots, arranged in a ring concentric with the pupil, occur in normal children but are far more frequent in…
Iritis

Inflammation of the iris. The iris is the circular, colored curtain in the front of the visible of the eye. (The opening of the iris forms the pupil.
Iron

An essential mineral. Iron is necessary for the transport of oxygen (via hemoglobin in red blood cells) and for oxidation by cells (via cytochrome). Deficiency of iron is a common cause of anemia. Food sources of iron…
Iron deficiency anemia

Anemia: The most common known form of nutritional disorder in the world, iron deficiency results in anemia because iron is necessary to make hemoglobin, key molecule in red blood cells responsible for the transport of…
Iron excess

Iron overload can damage the heart, liver, gonads and other organs. Iron overload is a particular risk for: > >People with certain genetic conditions such as hemochromatosis; and >People receiving repeated blood…
Iron overload

Iron overload: Iron overload can damage the heart, liver, gonads and other organs. Iron overload is a particular risk for: > >People with certain genetic conditions such as hemochromatosis; and >People receiving…
Iron poisoning

Iron supplements meant for adults (such as pregnant women) are a major cause of poisoning in children. Care should be taken to keep iron supplements safely away from children
Iron supplementation, infant

Iron is included in most infant formulas. Therefore, there is no evidence that iron supplementation is necessary for healthy formula-fed, full-term infants. In the past it was recommended that infants from birth to 4…
Irradiation

The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from…
Irradiation, food

See: Food irradiation
Irrigate

To wash out as, for example, a wound to clean it.
Irrigation of the colon

The use of liquid solutions given by enema to remove material from the rectum or colon, ostensibly to eliminate toxins from the bowel. Unless ordered by a physician, this practice is rarely advisable. Irrigation of the…
Irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS): A common gastrointestinal disorder involving an abnormal condition of gut contractions (motility) characterized by abdominal pain, bloating, mucous in stools, and irregular bowel habits…
Irritant contact dermatitis

Dermatitis: A rash brought about by constant irritation from a substance. For example, anyone who washes their hands many times a day can develop 'dish pan hands.' Another example is in young children who lick their…
Irwin DJ Bross

See: Bross, Irwin DJ
Ischemia

Inadequate blood supply (circulation) to a local area due to blockage of the blood vessels to the area.
Ischial bursitis

Bursitis: Inflammation of the bursa that separates the gluteus maximus muscle of the buttocks from the underlying bony prominence of the bone that we sit on, the ischial tuberosity. Ischial bursitis is a form of…
Ischium

Bone making up the lower down back part of the pelvis
Islet cell cancer

A rare but highly treatable type of pancreatic cancer that begins in the cells of the pancreas that produce insulin and other hormones. Islet cell cancer can cause the pancreas to produce too much insulin or other…
Islet cell carcinoma

See: Islet cell cancer
Islet cell tumor

See: Islet cell cancer
Islets of Langerhans

Known as the insulin-producing tissue, the islets of Langerhans do more than that. They are groups of specialized cells in the pancreas that make and secrete hormones. Named after the German pathologist Paul Langerhans…
Iso-

Composed of cells of the same size and type. Isocellular is a Greek-Latin hybrid term compounded from the Greek iso- meaning "equal or like" + the Latin cellula, the diminutive of cella, a storeroom.
Isocellular

Composed of cells of the same size and type. Isocellular is a Greek-Latin hybrid term compounded from the Greek iso- meaning 'equal or like' + the Latin cellula, the diminutive of cella, a storeroom
Isochromosome

An abnormal chromosome with two identical arms due to duplication of one arm and loss of the other arm. Isochromosomes are found in some girls with Turner syndrome, patients with the Pallister-Killian syndrome, and some…
Isochromosome 17q

An abnormal chromosome 17 with two identical long (q) arms due to duplication of the long arm and loss of the short arm. Isochromosome 17q is the most common isochromosome in cancer. It plays an important role in tumor…
Isodisomy

Remarkable situation where both chromosomes in a pair are from one parent and neither from the other. Isodisomy causes some birth defects and, we suspect, plays a role in cancer. Also called uniparental disomy.
Isoflavone

A type of plant estrogen (phytoestrogen) found chiefly in soybeans
Isoform

A protein that has the same function as another protein but which is encoded by a different gene and may have small differences in its sequence. For example, transforming factor beta (TGF-B) exists in three versions, or…
Isolate

A group in which mating is always between members of the group. For example, the Amish.
Isoleucine

An amino acid, one of the 20 building blocks of protein. A dietary essential amino acid, isoleucine is needed for optimal growth in childhood. It is one of the three branched-chain amino acids. Symbol: Ile