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.
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 river has a total drainage area exceeding 1,165,000 km 2 (450,000 sq mi). Its estimated annual flow stands at around 207 km 3 (50 cu mi), making it the twenty-first largest river in the world in terms of annual flow. The Zanskar is its left bank tributary in Ladakh.