evolutionarily conserved gene A gene that has remained essentially unchanged throughout evolution. Conservation of a gene indicates that it is unique and essential: There is not an extra copy of that gene with which evolution can tinker, and changes in the gene are likely to be lethal.
evolution, cultural See cultural evolution.
evolution, biologic See biologic evolution.
evolution The continuing process of change.
evidence-based medicine The judicious use of the best current available scientific research in making decisions about the care of patients. Evidence-based medicine (EBM) is intended to integrate clinical expertise with the research evidence and patient values.
event, adverse In pharmacology, an unexpected or dangerous reaction to a drug.
evening primrose oil A natural source of essential fatty acids (EFOs).
evacuation supplies kit See disaster supplies.
euthyroid The state of having normal thyroid gland function. See also hyperthyroid; hypothyroid.
euthanasia The hastening of death for a terminally ill patient. Euthanasia is from the Greek for “dying well.” See also active euthanasia; assisted suicide; eugenics.
Eustachian tube The tube that runs from the middle ear to the pharynx. The function of the Eustachian tube is to protect, aerate, and drain the middle ear and mastoid. The Eustachian tube permits the gas pressure in the middle ear cavity to adjust to external air pressure. When you are descending in an airplane,…
euploid The normal number of chromosomes for a species. In humans, the euploid number of chromosomes is 46; with the notable exception of the unfertilized egg and sperm, in which it is 23.