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.
One of the main rivers to be used in ancient times was the Indus river in the north-west (what is now north-western India and Pakistan).It was on the banks of the Indus river that the earliest civilization in India to use writing, build large buildings and organise cities flourished for nearly one thousand years.eography. The people of ancient India lived in a land of extremes. The terrain was varied and often presented great challenges. Occasional extremes of weather such as droughts and monsoons were also part of life in this land.