Medical Glossary Index:

I

Iatrogenic- a term used to describe a disease, disorder, or medical condition that is a direct result of medical treatment

Ichthyosis- a variety of diseases in which the skin is dry and scaly

Idiopathic- a term used to describe something that occurs of an unknown cause

Ileostomy- a surgical procedure in which the lower part of the small intestine (the ileum) is cut and brought to an opening in the abdominal wall, where feces can be passed out of the body

Ileum- the lowest section of the small intestine, which attaches to the large intestine

Ilium- one of the two bones that form the hip on either side of the body

Imaging- the technique of creating pictures of structures inside of the body using X-rays, ultrasound waves, or magnetic fields

Immune deficiency- impairment of the immune system, which reduces protection against infection and illness

Immune system- the cells, substances, and structures in the body that protect against infection and illness

Immunity- resistance to a specific disease because of the responses of the immune system

Immunization- the process of causing immunity by injecting antibodies or provoking the body to make its own antibodies against a certain microorganism

Immunocompromised- weakening of the body’s immune system

Immunodeficiency- failure of the body’s immune system to fight disease

Immunoglobin- proteins in blood and tissue fluids that help destroy microorganisms such as bacteria and viruses

Immunology- the study of the immune system, including how it functions and disorders that affect it

Immunostimulant- a drug that increases the ability of the body’s immune system to fight disease

Immunosuppressant- a drug that inhibits the activity of the immune system; used to prevent rejection of a transplant organ and in disorders where the body's immune system attacks its own tissues

Impacted fracture- a bone break in which the two broken ends have been
forced into each other

Imperforate anus- a birth defect in which the opening of the anus is not formed normally

Impetigo- a highly contagious skin infection caused by bacteria, usually occurring around the nose and mouth; commonly occurring in children

Implant- an organ, tissue, or device surgically inserted and left in the body

Impotence- the inability to acquire or maintain an erection of the penis

Incompetent cervix- an abnormally weak cervix, which widens prematurely during pregnancy as a result of the weight of a developing fetus; may result in a miscarriage

Incontinence- inability to hold urine or feces inside of the body

Incubation period- the time period between when an infectious organism enters the body and when symptoms occur

Indigestion- uncomfortable symptoms brought on by overeating or eating spicy, rich, or fatty foods; characterized by heartburn, pain in the abdomen, nausea, and
gas, and can be more serious if recurrent

Induction of labor- the use of artificial means to start the process of childbirth

Infarction- tissue death due to lack of blood supply

Infection- disease-causing microorganisms that enter the body, multiply, and damage cells or release toxins

Infective arthritis- arthritis caused by bacteria from a wound or the bloodstream entering a joint

Infertility- the inability to have children as a result of sexual intercourse

Inflammation- redness, pain, and swelling in an injured or infected tissue produced as a result of the body's healing response

Inflammatory bowel disease- the general term for two inflammatory disorders affecting the intestines; also known as Crohn's disease and ulcerative colitis

Inflammatory joint disease- any type of arthritis that causes a joint to become inflamed

Influenza- a viral infection characterized by headaches, muscle aches, fever, weakness, and cough; commonly called the "flu"

Informed consent- agreement to undergo a medical procedure after the technique, its risks, and its possible complications have been explained

Infusion- the introduction of a substance, such as a drug or nutrient, into the bloodstream or a body cavity

Ingestion- taking something into the body through the mouth

Ingrown toenail- a painful condition of the big toe in which the nail grows into the skin on either side, causing inflammation and/or infection

Inguinal hernia- the bulging of a portion of the intestines or abdominal tissue into the muscles of the groin (the area just below the abdomen)

Inhaler- a device used to introduce a powdered or misted drug into the lungs through the mouth, usually to treat respiratory disorders such as asthma

Inheritance- the passing of traits from parent to child through genes

Injection- the use of a syringe and needle to insert a drug into a vein, muscle, or joint or under the skin

Insemination- the placement of semen into a woman's uterus, cervix, or vagina

In situ- "in place"; often describes a cancer that has not spread

Insomnia- difficulty falling or remaining asleep

Insulin- a hormone made in the pancreas that plays an important role in the absorption of glucose (the body's main source of energy) into muscle cells

Insulinoma- a noncancerous tumor of the insulin-producing cells of the pancreas; the tumor releases excess insulin into the blood, causing glucose levels to drop dangerously low

Intensive care- close monitoring of a patient who is seriously ill

Interferon- a protein produced by body cells that fights viral infections and
certain cancers

Internal fixation- a method of holding a broken bone in place using surgically inserted screws, rods, or plates

Interstitial- lying between body structures or in the interspaces of tissues

Interstitial cystitis- persistent inflammation of the lining and muscle of the
bladder

Interstitial lung disease- a disease of the connective tissue surrounding the air sacs of the lungs that causes a dry cough, scarring of lung tissue, and shortness of breath

Interstitial pulmonary fibrosis- scarring of connective tissue in the lungs that leads to shortness of breath

Interstitial radiation therapy- a treatment for cancer in which a radioactive material is inserted into or near a tumor to provide direct radiation

Intervertebral disks- broad, flat cartilage structures containing a gel-like fluid that cushion and separate vertebrae

Intestinal bypass- a surgical procedure in which the beginning of the large intestine is joined to its end so that less food is absorbed; because of serious side effects, usually performed only on seriously obese people

Intestine- a long, tube-shaped organ that extends from the stomach to the anus; absorbs food and water and passes the waste products of digestion as feces

Intra-aortic balloon pump- a small balloon inserted into the aorta that helps to circulate blood by inflating between heartbeats

Intractable- describes a condition that does not respond to treatment

Intramedullary rod- a strong metal rod that is placed inside of a broken bone to help it heal correctly

Intraocular pressure- the pressure of the fluids within the eye

Intrauterine device- a device inserted into the uterus that helps to prevent pregnancy

Intravenous- inside of or into a vein

Intrinsic- a term used to describe something originating from or located in a
tissue or organ

Intubation- the passage of a tube into an organ or body structure; commonly
used to refer to the passage of a tube down the windpipe for artificial respiration

Invasive- describes something that spreads throughout body tissues, such as a tumor or microorganism; also describes a medical procedure in which body tissues are penetrated

In vitro- "in glass"; a biological test or process that is carried out in a laboratory

In vitro fertilization- a treatment for infertility in which an egg and a sperm are joined outside the woman's body, and the fertilized egg is then inserted into the uterus or fallopian tube

In vivo- "in the living body"; a biological process that occurs inside of the body

Involuntary- occurring without a person’s control or participation

Iodine- an element for the formation of thyroid hormones

Ionizing radiation- radiation that damages cells or genes; can be used to treat cancer

IQ- intelligence quotient; a measure of a person's intelligence as determined by specific tests

Iris- the colored part of the eye

Iron- a mineral necessary for the formation of important biological substances
such as hemoglobin, myoglobin, and certain enzymes

Iron-deficiency anemia- a type of anemia caused by a greater-than-normal loss of iron due to bleeding, problems absorbing iron, or a lack of iron in the diet

Irrigation- the cleansing of a wound by flushing it with water, a medicated solution, or some other fluid

Irritable bladder- involuntary contractions of muscles in the bladder, which can cause lack of control of urination

Irritable bowel syndrome- abnormal muscle movement in the intestines, which causes abdominal pain and irregular bowel movements (diarrhea, constipation, or both)

Ischemia- a condition in which a tissue or organ does not receive a sufficient supply of blood

IUD- see Intrauterine device

IVF- see In vitro fertilization