There are unknown amounts of fibers (fibre) in muscles
Sarcomere
The specific structure within a muscle cell that contains the sarcomere I band and is responsible for muscle contraction is called the myofibril.
muscle fibre
The specific function of the sarcomere H band within the structure of a muscle cell is to contain only thick filaments made of myosin, which are responsible for muscle contraction.
The myofibril is the basic muscle cell, within which is the sarcomere, the basic unit of muscle contraction.
The sarcomere is the basic functional unit of a muscle and is responsible for muscle contraction. It contains the proteins actin and myosin, which interact to generate muscle force. The sarcomere shortens when the actin and myosin filaments slide past each other, causing the muscle to contract.
thin filaments
Sarcomere
sarcomeresSarcomereSarcomeresThe functional unit of a skeletal muscle is called a sarcomere. Hole's Anatomy 12th edition, pg 287 states: "Muscle fibers, and in a way muscles themselves, are basically collections of sarcomeres, discussed later in this chapter as the functional units of muscle contraction."sarcomere.
sarcomere and sarcolemma are two different things. a sarcomere is between two d zisks of a myofiber (muscle fiber). a sarcolemma is a plasma membrane. there are many sections of sarcomere under the layer of sarcolemma.
Sarcomere
I do believe you are asking about a sarcomere, units of repeating bands that make up the fibers (myofibrils) of a striated muscle.