Research the causes of these diseases that are similar to, or related to, Autoimmune Urticaria: 1  Idiopathic urticaria without angioedema. 2  Chronic urticaria.  Occult infection (e.g., sinusitis, oral infection, cholecystitis, vaginitis, prostatitis, hepatitis, HIV, tinea manus or pedis)
The sarcoplasmic reticulum is known for its storage of calcium ions in muscle cells.
Best Answer: When sodium enters the muscle cell it creates an electrical impulse that travels down the cell membrane. This impulse travels to an indention of the membrane called a T-tubule. This allows the impulse to reach an intracellular structure called the SER(Smooth Endoplasmic Reticulum) which releases Calcium into the cell.