Detrusors

The detrusor muscle is a specialized type of smooth muscle found in the wall of the urinary bladder. Its primary function is to contract and relax, enabling the bladder to store and expel urine. During the filling phase of urination, the detrusor muscle relaxes, allowing the bladder to expand and hold a greater volume of urine. This relaxation is controlled by the sympathetic nervous system. When the bladder is sufficiently full, or when a person decides to urinate, the detrusor muscle contracts forcefully. This contraction increases the pressure within the bladder, forcing urine out through the urethra. This expulsive phase is primarily controlled by the parasympathetic nervous system. The coordinated action of the detrusor muscle and the sphincter muscles at the base of the bladder is essential for voluntary control of urination. Dysfunction of the detrusor muscle can lead to various urinary problems, including incontinence, difficulty emptying the bladder, or urinary retention. These issues can arise from neurological conditions, aging, or other medical factors affecting muscle function.