Dictionary

embryonic hemoglobin See hemoglobin E.

embryonic development See prenatal development.

embryonal rhabdomyosarcoma See sarcoma botryoides.

embryo An organism in the early stages of growth and differentiation, from fertilization to the beginning of the third month of pregnancy (in humans). After that point in time, an embryo is called a fetus.

embolus A blockage or plug that obstructs a blood vessel. Examples of emboli are detached blood clots, clumps of bacteria, and clumps of other foreign material, such as air.

embolization The clogging of small blood vessels with a substance that blocks the flow of blood. Embolization can occur as an abnormal natural event, such as when a blood clot travels from the leg to lodge in the blood vessels of the lungs, or it can be used as a treatment method, such as when…

embolism, paradoxical Passage of a clot (thrombus) from a vein to an artery. When clots in veins break off (embolize), they travel first to the right side of the heart and, normally, then to the lungs, where they lodge. The lungs act as a filter to prevent the clots from entering arterial circulation. However, when…

embolism, crossed See embolism, paradoxical.

embolism The obstruction of a blood vessel by a foreign substance or a blood clot that travels through the bloodstream, lodging in a blood vessel, plugging the vessel. Foreign substances that can cause embolisms include air bubbles, amniotic fluid, globules of fat, clumps of bacteria, chemicals (such as talc), and drugs (mainly illegal ones). Blood…

EM 1 Electron microscope. 2 Electron microscopy.

elliptocytosis A blood disorder characterized by elliptically shaped red blood cells with variable breakup of red cells (hemolysis) and varying degrees of anemia. Inherited as a dominant trait, elliptocytosis is due to the mutation of one of the genes that encodes proteins of the red cell membrane skeleton. There are several forms of elliptocytosis caused…

ELISA Enzyme-linked immunosorbent assay, a rapid immunochemical test that involves an enzyme used for measuring a wide variety of tests of body fluids. ELISA tests detect substances that have antigenic properties, primarily proteins rather than small molecules and ions, such as glucose and potassium. Some of these substances include hormones, bacterial antigens, and antibodies. ELISA…