<prompt> False about smooth muscleCa2 is the excitation-contraction couplerThe latch mechanism facilitates prolonged holding of contractions of smooth muscleShows the propey of plasticityMusculature of uterus is made of multi unit smooth muscle  <response>: Unitary smooth muscle is found primarily in the walls of hollow viscera like uterus, intestine, ureters. Multiunit smooth muscle is made up of individual units with few or no gap junctional bridges. It is found in structures such as the iris of the eye, in which fine, graded contractions occur. Depending on the activating stimulus, the Ca2 increase can be due to influx through voltage- or ligand-gated plasma membrane channels, efflux from intracellular stores through the RyR, efflux from intracellular stores through the inositol trisphosphate receptor IP3R Ca2 channel, or a combination of these channels. Smooth muscle behaves more like a viscous mass than a rigidly structured tissue, and it is this propey that is referred to as the plasticity of smooth muscle. .The latch mechanism facilitates prolonged holding of contractions of the smooth muscle. 