II. Muscles in vitro can exhibit twitch, summation, and tetanus. A. The rapid contraction and relaxation of muscle fibers is called a twitch. B. A whole muscle also produces a twitch in response to a single electrical pulse in vitro.1. The stronger the electric shock, the stronger the muscle twitch, whole muscles can produce graded contractions.2.. The motor neuron and the muscle fibers it innervates are called a motor unit. 1. When a muscle is composed of many motor units (such as in the hand), there is fine control of muscle contraction. 2. The large muscles of the leg have relatively few motor units, which are correspondingly large in size.
The Indus River, also called the SindhÅ« River (Sindhi: Ø³ÙÚÙ Ø¯Ø±ÙØ§ â), or AbÄsÄ«n (Pashto: Ø§Ø¨Ø§Ø³ÙÙ â) in Khyber Pakhtunkhwa, is one of the longest rivers in Asia.It flows through Pakistan, the Indian state of Jammu and Kashmir and western Tibet.he word India is derived from the Indus River. In ancient times, India initially referred to those regions immediately along the east bank of the Indus, but by 300 BC, Greek writers including Herodotus and Megasthenes were applying the term to the entire subcontinent that extends much farther eastward.
An Indus Valley site has been found on the Oxus River at Shortughai in northern Afghanistan, in the Gomal River valley in northwestern Pakistan, at Manda,Jammu on the Beas River near Jammu, India, and at Alamgirpur on the Hindon River, only 28 km from Delhi.he mature phase of the Harappan civilization lasted from c. 2600 to 1900 BCE. With the inclusion of the predecessor and successor cultures-Early Harappan and Late Harappan, respectively-the entire Indus Valley Civilization may be taken to have lasted from the 33rd to the 14th centuries BCE.