tonus

n. a continuous, slight stretching tension or contraction in muscles when they are at rest. For example, the jaw muscles exhibit tonus when not used for eating or talking. Tonus serves to keep the muscles ready for action. See also tonic.

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

January 20th 2025

night-eating syndrome

an eating disorder characterized by insomnia, nocturnal hyperphagia, and morning anorexia that persist for at least 3 months. Recent research suggests night-eating syndrome is related to hormonal irregularities and a disturbed circadian rhythm of food intake, although chronic stress may also be a contributing factor. This type of eating disorder is estimated to affect 1.5% of the global population and is thought to occur in 10–25% of obese individuals. [first described in 1955 by U.S. psychiatrist Albert J. Stunkard (1922–2014)]