Military forces have worn distinctive uniform items for centuries to create a psychological advantage and boost their esprit de corps, but the military use of berets is a relatively recent phenomenon. In the 16th and 17th centuries, the Blue Bonnet became a de facto symbol of Scottish Jacobite forces.
Muscle cells have adapted to their job by contracting and relaxing.  When calcium levels are increased the muscle cells contract. On the  other hand, when calcium levels droâ¦p the muscle cells get relaxed.
A muscle cell is a special kind of cell that makes up an organism's muscle tissues. The muscles allow independent movement and regulate biological functions such as digestion and heartbeat.n organism's muscle tissue is composed of muscle cells. Multi-unit smooth muscle cells operate independently and single-unit, or visceral, smooth muscle cells operate together as a unit. Muscle mass can be gained artificially from injections of performance-enhancing drugs and hormones.