Skeletal muscle contractions can be broadly separated into twitch, summation, and tetanic contractions. In a twitch contraction, a single action potential, whether from a motor neuron or from within the muscle, causes the muscle fiber to produce a single contraction and relaxation cycle called a twitch.uscle contractions can be described based on two variables: length and tension. A muscle contraction is described as isometric if the muscle tension changes but the muscle length remains the same. In contrast, a muscle contraction is isotonic if muscle length changes but the muscle tension remains the same.
Â© A Dictionary of Earth Sciences 1999, originally published by Oxford University Press 1999. Gutenberg discontinuity The seismic-velocity discontinuity between the Earth's mantle and core. The boundary is at a depth of about 2600 km and is thought to have surface irregularities of a few kilometres. Cite this article. Pick a style below, and copy the text for your bibliography.
Not to be confused with Serotonin syndrome. Antidepressant discontinuation syndrome is a condition that can occur following the interruption, dose reduction, or discontinuation of antidepressant drugs, including selective serotonin re-uptake inhibitors (SSRIs) or serotoninânorepinephrine reuptake inhibitors (SNRIs).