Talk about the smoot sarcoplasmic reticulum.

Sarcolemma has many transversal invaginations (T tubules) arranged around the junction zone between A and I bands of each myofibril. The T tubule network is called the transverse system. Smooth sarcoplasmic reticulum is located around each myofibril and runs parallel to it. It consists of tubules and sacs that periodically meet to form the terminal cisternae at each A-I bands junction. SER contains a high Ca++ concentration which release in the cytosol is responsible for the muscle contraction. SER cisternae are adjacent to either side of a T tubule. The 2 parallel terminal cisternae and the intervening T tubule form a complex referred to as the traid. At this level depolarization wave is transmitted from the T tubule to the sarcoplasmic reticulum.