Which term describes a stack of myofibrils in muscle tissue?

The term that describes a stack of myofibrils in muscle tissue is sarcomere. Sarcomeres are the basic contractile units of muscle fibers and are organized in repeating segments along the length of a myofibril. Each myofibril consists of a series of these sarcomeres arranged end to end, which is crucial for muscle contraction. The structured arrangement of actin and myosin filaments within each sarcomere facilitates the sliding filament mechanism, which is responsible for muscle contraction.

While myofilaments refer to the individual protein filaments (actin and myosin) that make up a sarcomere, and muscle fiber denotes an entire muscle cell made up of numerous myofibrils, the fascicle is a bundle of muscle fibers. Understanding the hierarchy of muscle structure—ranging from myofilaments to myofibrils to sarcomeres and muscle fibers—helps clarify the organization and function of muscle tissue.