ANATOMY

Detailed explanation-1: -Each bundle of muscle fiber is called a fasciculus and is surrounded by a layer of connective tissue called the perimysium . Within the fasciculus, each individual muscle cell, called a muscle fiber, is surrounded by connective tissue called the endomysium .

Detailed explanation-2: -Approximately 20–80 of these muscle fibers are grouped together in a parallel arrangement called a muscle fascicle or fiber bundle that is encapsulated by a perimysium, which is thicker than the epimysium enclosing each of the bundled muscle fibers.

Detailed explanation-3: -A muscle fascicle refers to a bundle of muscle fibers grouped together that are surrounded by a layer of connective tissue, called perimysium. Many myofibrils together combine to form a muscle fiber, and many muscle fascicles join function together to form a muscle.

Detailed explanation-4: -1 – The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles, are covered by the perimysium. Muscle fibers are covered by the endomysium.

Detailed explanation-5: -Myofibrils. Myofibrils are bundles of protein filaments that contain the contractile elements of the cardiomyocyte, that is, the machinery or motor that drives contraction and relaxation.