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.
1 In muscle cells, actin filaments are aligned and myosin proteins generate forces on the filaments to support muscle contraction. 2  In non-muscle cells, actin filaments form a track system for cargo transport that is powered by non-conventional myosins such as myosin V and VI. Microfilaments provide cell motility. 2  e.g., Filopodia, Lamellipodia. 3  During mitosis, intracellular organelles are transported by motor proteins to the daughter cells along actin cables. 4  In muscle cells, actin filaments are aligned and myosin proteins generate forces on the filaments to support muscle contraction.