Such a contraction is called a twitch. Thus, each motor unit is either relaxed or each presynaptic action potential causes an action potential in all of the muscle fibers of the motor unit, causing them all to contract at once.In the whole muscle, contractions of different strengths necessarily are created by activating different numbers of motor units.hus, each motor unit is either relaxed or each presynaptic action potential causes an action potential in all of the muscle fibers of the motor unit, causing them all to contract at once. In the whole muscle, contractions of different strengths necessarily are created by activating different numbers of motor units.
Johannes Gutenberg of Mainz, Germany is acknowledged as the first to invent a metal movable-type printing system in Europe, the printing press.
the printing surface. To produce a copperplate engraving, a drawing is scratched into a smooth metal plate. Johann Gutenberg invented printing press and produced the forty-two line bible. Johann Fust Often called the inventor or printing he is said to take some of the credit from Gutenberg and printing. Peter Schoeffer Gutenbergâs assistant. Also was an artist/designer experienced as an illumina