Which structure surrounds an individual muscle cell?

The correct answer is endomysium, which is the layer of connective tissue that surrounds each individual muscle cell, also known as a muscle fiber. The endomysium is crucial because it not only provides a supportive environment for each muscle cell but also contains the necessary blood vessels and nerves that supply the muscle fibers. This structure helps facilitate the exchange of nutrients and waste products between muscle cells and the bloodstream, contributing to muscle health and function.

In contrast, epimysium is the outer layer of connective tissue that encases an entire muscle, providing protection and structural integrity. Perimysium surrounds bundles of muscle fibers (fascicles) within the muscle, creating compartments and also containing blood vessels and nerves that supply those bundles. Fascia refers to a broader term for connective tissue that can surround muscles, groups of muscles, or organs, rather than specifically surrounding individual muscle cells.