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.
In order for muscle fibers to contract, a lot of ATP must be used (see Sarcomere Contraction Figure). Some of the energy released from ATP is used to power the contraction. Interestingly, ATP is also necessary for a contracted muscle cell to ârelaxâ as well.alcium isnât just important for bone, it is also the key factor that initiates muscle contraction. When skeletal muscle fibers become excited, calcium channels open and calcium floods in and around the myofibrils and bathes the sarcomeres.