- 1. A state of normal tension of the tissues by virtue of which the parts are kept in shape, alert, and ready to function in response to a suitable stimulus. In the case of muscle, it refers to a state of continuous activity or tension beyond that related to the physical properties; i.e., it is active resistance to stretch; in skeletal muscle it is dependent upon the efferent innervation. SYN: tonus. 2. The osmotic pressure or tension of a solution, usually relative to that of blood. SEE ALSO: isotonicity. [G. tonos, tone]
* * *1) the property of possessing tone esp healthy vigor of body or mind2) TONUS (2)3) the osmotic pressure of a solution <the cells swell and shrink with changing \tonicity of the environment>
* * *n.1. the normal state of slight contraction, or readiness to contract, of healthy muscle fibres.
* * *to·nic·i·ty (to-nisґĭ-te) 1. the state of tissue tone or tension. 2. in body fluid physiology, the effective osmotic pressure equivalent.
Medical dictionary. 2011.