facial nerve paralysis Loss of voluntary movement of the muscles of one side of the face due to abnormal function of the facial nerve. Paralysis of the facial nerve causes a characteristic drooping of one side of the face, inability to wrinkle the forehead, inability to whistle, inability to close an eye, and deviation of…
exercise-induced asthma See asthma, exercise-induced.
exercise-induced bronchospasm See asthma, exercise-induced.
exfoliate 1 To peel off scaly skin spontaneously. For example, the skin exfoliates from the palms and soles in psoriasis, Kawasaki disease, and Reiter syndrome. 2 To deliberately wear away the top layer of skin, as may be done gently by a facial technologist who is applying a topical skin treatment for cosmetic purposes or…
exocrine Pertaining to the secretion of a substance out of the body through a duct. The exocrine glands include the salivary glands, sweat glands, and glands within the gastrointestinal tract. Exocrine is as opposed to endocrine, which refers to the secretion of a substance (a hormone) within the body through the bloodstream. See also endocrine.
exogenous Originating from outside an organism. For example, insulin taken by a diabetic is exogenous insulin. See also endogenous.
exon A region of DNA in a gene that is transcribed (read) into mature messenger RNA. An exon is the protein-coding part of a gene. See also intron.
exonuclease An enzyme that cleaves nucleotide bases sequentially from the free ends of a nucleic acid (DNA or RNA).
exophthalmos A condition in which the patient has protruding eyeballs, as in Graves disease.
exotropia Divergent gaze. Also known as external strabismus and, pejoratively, walleye.
expectorant A medication that helps bring up mucus and other material from the lungs, bronchi, and trachea. An example of an expectorant is guaifenesin, which promotes drainage of mucus from the lungs by thinning the mucus, and also lubricates the irritated respiratory tract.
exposure In cognitive behavioral therapy, the process of exposing oneself to an event or a place that causes anxiety or panic. The intention of controlled exposure is to gradually lower the level of stress and anxiety associated with the stimulus, to eventually prevent panic attacks, obsessive-compulsive behaviors, and other unwanted reactions. See also cognitive behavior…