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…
EM 1 Electron microscope. 2 Electron microscopy.
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…
embolism, crossed See embolism, paradoxical.
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…
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…
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.
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.
embryonal rhabdomyosarcoma See sarcoma botryoides.
embryonic development See prenatal development.
ejection fraction The percentage of blood that is pumped out of a filled ventricle as a result of a heartbeat. The heart does not eject all the blood in the ventricle. Only about two-thirds of the blood is normally pumped out with each beat, and that fraction is referred to as the ejection fraction. The…
EKG Electrocardiogram.