fasciclea

A fascicle is a small bundle or cluster of structures, most commonly referring to a bundle of muscle fibers or nerve fibers. In anatomy, a fascicle is a distinct unit within a larger organ, such as a muscle. Muscle fascicles are groups of muscle cells (myocytes) that are bundled together by connective tissue called the perimysium. The arrangement of these fascicles within a muscle influences its strength and range of motion. For example, parallel fascicles run along the length of the muscle, while pennate fascicles are arranged at an angle to the tendon.

Similarly, in the nervous system, a fascicle can refer to a bundle of axons, which are the long, slender projections of nerve cells. These nerve fascicles are surrounded by a connective tissue sheath called the endoneurium and are grouped together within larger nerve structures. The organization of axons into fascicles helps to protect the nerve fibers and allows for efficient transmission of neural signals. The term fascicle can also be used more broadly in botany to describe a cluster of leaves or stems, such as those found on certain pine trees. In literature, a fascicle is also a section or installment of a larger work, often published serially.