Cytology and General Histology: Atlas

Muscle tissues

This is a group of tissues providing for body locomotion and movements of its parts due to a presence of specialized intracellular contractile structures.
The muscle tissue locomotive function is structurally based on a universal mechanical & chemical contractile system, which is constituted by a number of fibrillar structures (filaments) consisting of such proteins as actin and myosin.
A muscle contracts when actin filaments change their position in relation to myosin filaments with no change in length in any of them (sliding filament theory) due to interaction of their proteins.