Myosin makes up the THICK filaments, and actin makes up the thin filaments of myofibrils.
Myofibrils are made up of actin (thin filaments) and myosin (thick filaments).
The sarcoplasmic reticulum are the membranous interconnecting channels and sacs that surround and run parallel to the myofibrils.
Myofibrils
myofibrils
The sarcomere is the contractile unit. It is the space between two Z discs that contains one group of myosin fillaments and two groups of actin fillaments, one group on each end of the myosin fillaments. Z discs join sarcomeres together end-to-end to form myofibrils. A group of myofibrils surrounded by the sarcolema makes up a muscle fiber.
myofibrils
myofibrils
actin and myosin
myofibrils
The sarcoplasm
True.