Penicillin has changed over the course of history because it is used to prevent bacteria from spreading and without it, the human population would either be dead or contribute to a disease
Each muscle is surrounded by a connective tissue sheath called the epimysium. ... Within the fasciculus, each individual muscle cell, called a muscle fiber, is surrounded by connective tissue called the endomysium. Skeletal muscle cells (fibers), like other body cells, are soft and fragile.
