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.
Continuity and Discontinuity. Functions which have the characteristic that their graphs can be drawn without lifting the pencil from the paper are somewhat special, in that they have no funny behaviors. The property which describes this characteristic is called continuity.