The driving age should be raised up to 18 because teens can be a little careless. Driving at the age of 18 is a more mature age for teens because they can have more responsibility. Teens should not be driving at the age of 16 because they could be texting and driving or drinking and driving with some friends.
During contraction, the smooth-muscle cell's intermediate filaments help to draw the cell up, like closing a drawstring purse. Calcium ions regulate contraction in smooth muscle, but they do it in a slightly different way than in skeletal muscle: Calcium ions come from outside of the cell. Calcium ions bind to an enzyme complex on myosin, called calmodulin-myosin light chain kinase.
Generally, smooth muscle has to be able to contract continuously at a low level of intensity. The structure of smooth muscle enables it to function in this manner and differentiates it from other types of muscle found in the heart and musculature of the arms, legs, back and trunk.he nucleus of a smooth muscle cell, which contains the DNA, is located in the center of the cell, where the cell is widest. In the vicinity of the nucleus are various organelles, which are individual structures with specific cell functions.