Dictionary

oliguria Less urination than normal.

Ollier’s disease See multiple enchondromatosis.

omega-3 fatty acids A class of fatty acids found in fish oils, especially salmon and other cold-water fish, that acts to lower the levels of total cholesterol and LDL cholesterol in the blood. Omega-3 fish oil is considered a neutraceutical, a food that provides health benefits. Eating fish has been reported to protect against age-related…

omentum A sheet of fat that is covered by peritoneum. The greater omentum is attached to the bottom edge of the stomach and hangs down in front of the intestines. Its other edge is attached to the transverse colon. The lesser omentum is attached to the top edge of the stomach and extends to the…

Ommaya reservoir A device that is implanted under the scalp to deliver anticancer drugs to the fluid surrounding the brain and spinal cord.

omphalo- Prefix indicating a relationship to the umbilicus (the navel). From the Greek word for the decorative boss protruding from the center of a Greek warrior’s shield.

omphalocele A birth defect in which part of the intestine, covered only by a thin transparent membrane, protrudes outside the abdomen at the umbilicus. An omphalocele occurs due to a failure during embryonic development for a section of the intestines (the midgut) to return from outside the abdomen and reenter the abdomen as it should….

omphalomesenteric duct A narrow tube that is present in the early embryo that connects the midgut of the embryo to the yolk sac outside the embryo through the umbilical opening. Later in development, it is usually obliterated, but a remnant of it may persist, most commonly as a finger-like protrusion from the small intestine that…

onchocerciasis See river blindness.

oncogene A gene that contributes to the transformation of normal cells into cancerous cells. Many oncogenes are genes that had a normal role in the cell (proto-oncogenes) and were altered by mutation to become oncogenes. See also proto-oncogene.

oncologist A physician who specializes in the diagnosis and treatment of cancer. After a cancer diagnosis is made, it is the oncologist’s role to explain the cancer diagnosis and the meaning of the disease stage to the patient; discuss various treatment options; recommend the best course of treatment; deliver optimal care; and improve quality of…

oncology The field of medicine that is devoted to cancer. Clinical oncology consists of three primary disciplines: medical oncology (the treatment of cancer with medicine, including chemotherapy), surgical oncology (the surgical aspects of cancer including biopsy, staging, and surgical resection of tumors), and radiation oncology (the treatment of cancer with therapeutic radiation).