Dominic Stone
The detrusor muscle, also known as the detrusor urinae muscle or the muscularis propria of the urinary bladder, is a smooth muscle found in the wall of the bladder. The detrusor muscle is innervated by the autonomic nervous system and plays a crucial role in the storage and release of urine. During urination, the detrusor muscle contracts to release urine, while at other times, it remains relaxed to allow the bladder to store urine. The detrusor muscle is located in the wall of the bladder and extends over much of its body and base.
| Characteristics | Values |
|---|---|
| Location | Wall of the bladder |
| Composition | Smooth muscle cells |
| Function | Contracts during voiding events to expel urine from the bladder |
| Control | Autonomic nervous system |
| Relaxation | Sympathetic branches from the inferior hypogastric plexus |
| Contraction | Parasympathetic pelvic splanchnic nerves |
| Issues | Can cause problems in voiding the bladder in older adults, leading to uncomfortable urinary retention |
Explore related products
What You'll Learn
The detrusor muscle is located in the bladder wall
The detrusor muscle, also known as the detrusor urinae muscle, is a smooth muscle found in the bladder wall. It is the muscularis propria component of the bladder. The bladder is a hollow muscular organ located in the pelvis, just above and behind the pubic bone. The detrusor muscle is responsible for the contraction of the bladder during urination, allowing urine to be released from the body.
The detrusor muscle is composed of smooth muscle cells (SMCs) that are organised in three sheets. Two longitudinal smooth muscle sheets surround a middle, circular smooth muscle sheet. This interlacing network of multi-directional smooth muscle fibres produces a trabeculated appearance. The detrusor muscle extends over much of the bladder body and base, but its smooth musculature differs from that of the ureter orifices/distal ureters, trigone, and urethra.
The detrusor muscle is innervated by the autonomic nervous system, which controls its contraction and relaxation. During urination, parasympathetic pelvic splanchnic nerves act on postganglionic M3 receptors to cause contraction of the detrusor muscle. This contraction, combined with the relaxation of the urethral sphincter muscles, leads to urination. At other times, the detrusor muscle remains relaxed, allowing the bladder to store urine. This relaxation is maintained by sympathetic branches from the inferior hypogastric plexus.
The detrusor muscle plays a crucial role in bladder function, and abnormalities or pathology of this muscle can lead to urinary retention, incontinence, or a combination of both. In older adults over 60 years of age, the detrusor muscle may cause issues in voiding the bladder, resulting in uncomfortable urinary retention. Therefore, the proper functioning of the detrusor muscle is essential for maintaining urinary health and comfort.
Muscle Repair: The Power of Proteins
You may want to see also
Explore related products
It is made of smooth muscle cells
The detrusor muscle, also known as the detrusor urinae muscle or muscularis propria of the urinary bladder, is a smooth muscle found in the wall of the bladder. It is made of smooth muscle cells (SMC) that are organised in three sheets. Two longitudinal smooth muscle sheets surround a circular smooth muscle sheet in the middle. The detrusor muscle extends over much of the bladder's body and base.
The detrusor muscle is an interlacing network of multi-directional smooth muscle fibres that produce a trabeculated appearance on gross inspection. Only close to the internal urethral meatus do the fibres orient themselves into three specific layers: inner longitudinal, middle circumferential, and outer longitudinal. These layers form the proximal bladder neck sphincter. The detrusor muscle in males is better developed than in females as greater pressure is needed to overcome the resistance posed by the longer male urethra.
The detrusor muscle is innervated by the autonomic nervous system. During urination, parasympathetic pelvic splanchnic nerves act on postganglionic M3 receptors to cause contraction of the detrusor muscle. The bladder afferent neurons, located in the bladder wall, sense the bladder's expansion during filling. At other times, the muscle is kept relaxed via sympathetic branches from the inferior hypogastric plexus to allow the bladder to fill.
The detrusor muscle is responsible for allowing the bladder to contract to excrete urine or relax to hold urine. The combination of detrusor contraction and urethral sphincter relaxation leads to urination. The bladder is a hollow muscular organ in the pelvis, just above and behind the pubic bone. Its two main functions are the storage and emptying of urine.
Activating Your Scapular Muscles: A Comprehensive Guide
You may want to see also
Explore related products
The detrusor muscle contracts during urination
The detrusor muscle is a smooth muscle found in the wall of the bladder. It is also known as the detrusor urinae muscle, muscularis propria of the urinary bladder, or simply muscularis propria. The primary function of the detrusor muscle is to contract during urination to push urine out of the bladder and into the urethra.
During urination, the parasympathetic nervous system stimulates the bladder, causing the detrusor muscle to contract. Specifically, the parasympathetic pelvic splanchnic nerves act on postganglionic M3 receptors to cause this contraction. When the bladder is full, the M3 receptors are stretched and stimulated, leading to the contraction of the detrusor muscle. At the same time, the parasympathetic fibres inhibit the internal urethral sphincter, causing it to relax and allowing for bladder emptying.
The combination of detrusor contraction and urethral sphincter relaxation leads to urination. The detrusor muscle contracts to push urine out of the bladder, while the urethral sphincter muscles envelop the urethra and control the flow of urine when they contract. The ureter passes obliquely through the detrusor muscle to prevent the reflux of urine into the kidney as the bladder fills.
At other times, when urination is not occurring, the detrusor muscle remains relaxed to allow the bladder to store urine. The muscle is kept relaxed through sympathetic branches from the inferior hypogastric plexus, allowing the bladder to fill. This relaxation is important for bladder function, as the bladder stretches and expands during bladder filling.
Understanding Muscle Flexing: The Science Behind Movement
You may want to see also
Explore related products
It is controlled by the autonomic nervous system
The detrusor muscle is located in the wall of the bladder and is composed of smooth muscle. It is innervated by the autonomic nervous system (ANS), which lies outside of the central nervous system. The ANS regulates the actions of internal organs that are under involuntary control. It is divided into the sympathetic and parasympathetic nervous systems, which function in opposition to one another.
The sympathetic nervous system causes the bladder to increase its capacity without increasing detrusor resting pressure, allowing the bladder to relax and fill with urine. The parasympathetic nervous system stimulates the detrusor to contract, causing the bladder to release urine. During urination, the sympathetic influence on the internal urethral sphincter is suppressed, allowing the internal sphincter to relax and open. This suppression, along with the action of the parasympathetic nervous system, facilitates voluntary urination.
The detrusor muscle contracts during urination to release urine and remains relaxed to allow the bladder to store urine. The urethral sphincter muscles envelop the urethra and control the flow of urine when they contract. The combination of detrusor contraction and urethral sphincter relaxation leads to urination.
In older adults over 60 years of age, the detrusor muscle may cause issues in voiding the bladder, resulting in uncomfortable urinary retention. Detrusor muscle pathology can lead to urinary retention, incontinence, or a combination of both. Abnormalities of the detrusor muscle, if left untreated, can lead to deterioration of the upper urinary tracts.
Unraveling the Mystery of Oblique Muscles: How Many and Their Functions
You may want to see also
Explore related products
The male detrusor muscle is better developed than the female's
The detrusor muscle, also known as the detrusor urinae muscle or the muscularis propria of the urinary bladder, is a smooth muscle found in the wall of the bladder. It is responsible for allowing the bladder to contract to excrete urine or relax to store urine. The detrusor muscle is innervated by the autonomic nervous system, which controls its contraction and relaxation.
In males, the detrusor muscle fibres arise from the posterior surface of the body of the pubis and the adjacent part of the prostate. These fibres pass longitudinally up the inferior surface of the bladder, over its apex, and then descend along its fundus to become attached to the prostate. On the other hand, in females, the fibres arise from the posterior surface of the body of the pubis and attach to the front of the vagina.
The detrusor muscle in males is better developed than in females due to the greater pressure required to overcome the resistance posed by the longer male urethra. This difference in urethral length between the sexes leads to variations in the development of the detrusor muscle. The male detrusor muscle generates more pressure to overcome the resistance in the longer urethra, resulting in a more well-developed muscle.
Additionally, the blood supply to the bladder differs between the sexes. In males, the upper portion of the bladder is supplied by the superior vesical artery, while the lower portion receives blood from the inferior vesicular artery. In contrast, the female bladder receives its blood supply from the vaginal arteries for the lower portion and the superior vesical artery for the upper portion.
Understanding the differences in the detrusor muscle between males and females is essential for comprehending the unique urinary functions and potential pathologies associated with each sex. The better development of the male detrusor muscle compared to the female muscle is a result of the anatomical and physiological differences between the sexes, specifically in relation to the urinary system.
Neck Muscle Anatomy: Understanding the Complexity
You may want to see also
Frequently asked questions
The detrusor muscle is located in the wall of the bladder.
The detrusor muscle is made of smooth muscle cells (SMC) organised in three sheets.
The detrusor muscle contracts during urination to release urine and remains relaxed to allow the bladder to store urine.
If the detrusor muscle is not functioning properly, it can lead to issues with voiding the bladder, resulting in uncomfortable urinary retention. It can also lead to incontinence or deterioration of the upper urinary tracts if left untreated.
