1 Only appointments for producers with active licenses on PDB will be renewed. 2  Appointment Renewal Invoices and the list of appointment renewals due will be available on the NIPR website beginning 8:00 AM Central Time, November 1, 2015 through 4:00 PM Central Time December 31, 2015. 3  NIPR website link is: www.nipr.com.
Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thick and thin filaments called myofilaments, which repeat along the length of the myofibril in sections called sarcomeres.
transverse tubules. structures in myofibers which run transversely to the long axis of the myofibrils in skeletal and cardiac muscle. They are filled with basal lamina material and are part of the communication system of muscle fibers and provide a means for the passage of action potentials into the depths of the fibers.