A detrusor is the smooth muscle of the urinary bladder wall that facilitates urination. It is composed of smooth muscle fibers oriented in multiple directions.
Understanding the Detrusor Muscle
The detrusor muscle plays a crucial role in the urinary system. Here's a detailed look at its function and characteristics:
- Structure: The detrusor muscle consists of smooth muscle fibers with an interwoven orientation. According to the provided text, "The wall of the bladder is comprised of smooth muscle fibers oriented in multiple different directions. These smooth muscle fibers are collectively known as the detrusor muscle."
- Function: The primary function is to contract and expel urine from the bladder during urination.
- Flexibility: Its unique interwoven orientation allows the bladder to stretch and accommodate varying volumes of urine. The reference text confirms this, stating, "This interwoven orientation provides the bladder with the ability to stretch in response to the presence of urine."
Role in Urination
When the bladder is full, signals are sent to the brain, initiating the urination process. The detrusor muscle then contracts, increasing pressure within the bladder, while the sphincter muscles relax to allow urine to flow out through the urethra.
Clinical Significance
Dysfunction of the detrusor muscle can lead to various urinary problems, including:
- Overactive Bladder (OAB): Characterized by frequent and urgent urination due to involuntary detrusor muscle contractions.
- Underactive Bladder: Occurs when the detrusor muscle is weak or unable to contract properly, leading to urinary retention.
