In 2015 Illinois will again process all appointment renewals electronically through the National Insurance Producer Registry (NIPR). 1  Appointment renewal date is November 1, 2015. 2  Appointment renewals will be electronically processed through NIPR.
myofibril - one of many contractile filaments that make up a striated muscle fiber. myofibrilla, sarcostyle. sarcoplasm - the cytoplasm of a striated muscle fiber. striated muscle cell, striated muscle fiber - an elongated contractile cell in striated muscle tissue.
A muscle fiber contains many myofibrils, which are cylinders of muscle proteins. These proteins allow a muscle cell to contract. Myofibrils contain two types of filaments that run along the long axis of the fiber, and these filaments are arranged in hexagonal patterns. There are thick and thin filaments.hese proteins allow a muscle cell to contract. Myofibrils contain two types of filaments that run along the long axis of the fiber, and these filaments are arranged in hexagonal patterns. There are thick and thin filaments.