Bladder smooth muscle or sphincter?

The bladder

is an organ of the urinary system, including smooth muscle and sphincter. The smooth muscle is a component of the bladder wall and can help the body to expel urine through contraction and relaxation. The sphincter is located in the neck of the bladder and has an external sphincter and an internal sphincter. It is a muscle controlled by consciousness and is usually controlled by autonomic nerves. When the body produces urine and decides to urinate, it can cause the sphincter to relax and expel urine through nerve conduction. When the body needs to control urination, it can contract the sphincter through nerve conduction to prevent urine from flowing out.