An era is a commonly used word for a long period of time. When used in science, for example geology, an era denotes a clearly defined period of time of arbitrary but well-defined length, such as for example the Mesozoic Era from 252 Maâ66 Ma, delimited by a start event and an end event.
As you increase voltage to the muscle describe how it responds to the increased stimulus. As the voltage was increased from threshold to maximum voltage, there was a greater force in the muscle contraction. Once the maximum voltage (2500 mv) was reached, even if there was an increase in voltage, the force of the muscle contraction remained the same.
The specific contraction requirements of a particular muscle determine the type of motor units found in that muscle. Muscles which must produce great tension but are only called on periodically will likely incorporate a high percentage of type A motor units in their organization.he innervation ratio represents the number of muscle fibers innervated by a single motor nerve fiber. A small motor unit might have an innervation ratio as low as 10:1. Some of the large motor units of the gastrocnemius have been estimated to be as high as 2000:1.