Alec Titan
The urinary bladder is a hollow, spherical organ that holds urine. It is located in the abdomen and is surrounded by the pelvic diaphragm, peritoneum, endopelvic fascia, and the rectus abdominis muscle. The bladder is supported by the muscles of the pelvic floor, which include the external urethral sphincter, the levator ani muscle, and the rectourethralis muscle. The bladder itself is made up of smooth muscle, known as the detrusor muscle, which contracts to release urine and relaxes to store urine.
| Characteristics | Values |
|---|---|
| Location | Posterior to the pubic symphysis |
| Protection | Guarded by the rigid pelvic ring and the rectus abdominis muscle |
| Shape | Hollow, spherical |
| Size | 2 inches when empty, 6 inches when full |
| Layers | 3 |
| Inner Layer | Urothelium |
| Middle Layer | Lamina Propria (Submucosa) |
| Outer Layer | Muscularis Propria (smooth muscle) |
| Muscles | Detrusor Muscle, Sphincter Muscles, Pelvic Floor Muscles |
| Nerves | Parasympathetic, Sympathetic, Somatic |
Explore related products
What You'll Learn
The pelvic floor supports the bladder and urethra
The pelvic floor muscles support the bladder and the urethra. These muscles span the bottom of the pelvis and support the pelvic organs, including the bladder and the bowel, and the uterus in women. The pelvic floor muscles give people control over the release of urine, faeces, and flatus, and to delay emptying until it is convenient.
The pelvic floor muscles wrap tightly around the urethra, vagina, and anus, helping to keep them shut. They are also important for sexual function in both men and women. In men, the pelvic floor muscles are important for erectile function and ejaculation. The pelvic floor muscles can be exercised and strengthened, which can improve bladder and bowel function and sexual function.
When the bladder is full of urine, it is the largest organ in the urinary tract. The bladder is a hollow, spherical-shaped organ that holds urine. When the bladder is full, it expands like a balloon and can hold 500-700 mL of urine. The bladder is well-protected in adults as it lies within the confines of the bony pelvis. The rigid pelvic ring and the rectus abdominis muscle guard it.
The bladder neck is a narrow group of muscles that connect to the urethra. The detrusor muscle is located within the walls of the bladder and is composed of smooth muscle fibres that are longitudinal and circular. When the bladder is full, the detrusor muscle contracts to push urine out of the bladder and into the urethra. The urethra extends from the bladder neck to the urethral meatus. The female urethra is approximately 4 cm long and lies posterior to the symphysis pubis, adjoining the anterior vaginal wall.
The pelvic floor muscles can become weakened during pregnancy, from overuse, or from hormone changes during menopause. Weakened pelvic floor muscles can lead to stress incontinence, which is when someone experiences peeing or dribbling when laughing, coughing, sneezing, or lifting. Pelvic floor exercises can help to prevent and treat this condition.
Muscle Movement: Acid Produced by Muscles
You may want to see also
Explore related products
The detrusor muscle contracts the bladder
The detrusor muscle, also known as the detrusor urinae muscle or muscularis propria, is a smooth muscle that forms the walls of the bladder. It is responsible for the contraction of the bladder during urination, allowing urine to be released from the body. The process of urination involves the coordination of the contraction of the detrusor muscle and the relaxation of the urethral sphincter.
The detrusor muscle is composed of smooth muscle fibres that are oriented in multiple directions, including longitudinal and circular arrangements. These fibres are interwoven, providing the bladder with the ability to stretch and expand as it fills with urine. The detrusor muscle is under the control of the autonomic system, specifically regulated by the parasympathetic nervous system and sympathetic nervous system. When the bladder fills with urine, the parasympathetic nervous system stimulates the M3 muscarinic stretch receptors in the bladder, leading to the contraction of the detrusor muscle. Simultaneously, the parasympathetic fibres inhibit the internal urethral sphincter, causing it to relax and prepare for bladder emptying.
During urination, the contraction of the detrusor muscle pushes the urine out of the bladder and into the urethra. The urethral sphincter muscles envelop the urethra and control the flow of urine by contracting or relaxing. When the bladder is empty, the sympathetic nervous system is stimulated, causing the relaxation of the detrusor muscle and allowing the bladder to fill with urine again. This process is essential for maintaining urinary function and ensuring the bladder can store and release urine effectively.
The detrusor muscle is derived from the upper segment of the urogenital sinus in the fetus and is connected to the allantois, which eventually becomes the urachus. The blood supply to the detrusor muscle and the bladder varies between males and females. 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 females, the lower portion of the bladder is supplied by the vaginal artery. Additionally, there is a minor blood supply through the inferior gluteal and obturator arteries.
Disturbances in the function of the detrusor muscle can lead to urinary retention, incontinence, or a combination of both. Abnormalities in the detrusor muscle, if left untreated, can result in the deterioration of the upper urinary tracts. Therefore, it is important to identify and address any issues related to the detrusor muscle to maintain overall urinary health and function.
Stimulating Muscle Tetanus: Electric Shock Therapy and More
You may want to see also
Explore related products
The external urethral sphincter is under voluntary control
The bladder is a hollow, spherical-shaped organ that holds urine. It is located in the abdomen and is considered the largest organ in the urinary tract when it is full. The bladder is surrounded and protected by the rigid pelvic ring and the rectus abdominis muscle. The bladder neck, located at the base of the bladder, is a narrow group of muscles that connect to the urethra. The urethra is a small tube that connects the bladder to the genitals for the removal of fluids from the body.
The urethral sphincter is an important part of the closing mechanism of the urinary tract outlet. It consists of the internal urethral sphincter (IUS) and the external urethral sphincter (EUS). The EUS is a true annular sphincter that surrounds the urethra. It is part of the pelvic floor musculature and is composed of striated muscle. In females, the EUS is more elaborate than in males as it includes the urethrovaginal sphincter. The EUS is innervated by the pudendal nerve, which is part of the somatic nervous system.
The detrusor muscle, located within the walls of the bladder, is responsible for contracting during urination to push urine out of the bladder and into the urethra. It is composed of smooth muscle fibers that are arranged longitudinally and circularly in layers. The contraction of the detrusor muscle and the relaxation of the urethral sphincter work together to facilitate urination.
Masturbation: Impact on Muscle Strength and Weakness
You may want to see also
Explore related products
The bladder neck is a narrow group of muscles
The bladder neck is formed by several structures, including the detrusor muscle, the vesical sphincter, and adjacent proximal prostatic tissue. The detrusor muscle is a densely interwoven network of three recognised smooth muscle layers: an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The detrusor muscle is under autonomic control and is composed of smooth muscle. It is responsible for the contraction of the bladder during urination to push urine out of the bladder and into the urethra. The detrusor muscle will relax to allow the storage of urine in the bladder.
The vesical sphincter is a muscular structure that assures continuous urinary continence as well as bladder neck closure during ejaculation to avoid retrograde ejaculation. The bladder neck is also surrounded by neuronal tissue, which is the least mobile part of the bladder.
Problems in the muscles that form the bladder neck can lead to urinary issues. For example, bladder neck contracture can cause more pressure on the bladder, which can lead to permanent kidney damage from backup urine. Bladder neck elevation (BNE) is another condition that can cause urination problems such as benign prostatic hyperplasia (BPH) and urethral stenosis in men. BNE is characterised by an elevation angle of 35 degrees or above during cystourethroscopy, which can lead to symptoms similar to lower urinary tract complaints.
Muscle Attachments: Visual Memory Techniques for Efficient Learning
You may want to see also
Explore related products
The rectus abdominis muscle guards the bladder
The rectus abdominis is one of the largest and most important muscles of the abdomen region, playing a key role in flexing the spine, stabilising the trunk, and maintaining posture. It acts to flex the spinal column, tense the anterior wall of the abdomen, and assist in compressing the contents of the abdomen. Together with the back muscles, the abdominal muscles make up the "core" muscles, helping to protect the spine and keep the body stable and balanced. The abdominal muscles hold internal organs in place and protect them. This includes organs such as the stomach, intestines, pancreas, liver, gallbladder, and other organs.
The bladder is the organ in the abdomen that holds urine before it leaves the body. It is a hollow, spherical-shaped organ that can hold 500-700 mL (about two cups) of urine. When the bladder is full of urine, it is the largest organ in the urinary tract. The bladder is well-protected in adults as it lies within the confines of the bony pelvis. The rigid pelvic ring and the rectus abdominis muscle guard it. The bladder occupies a less protected position in infants and children, as it is a more abdominal organ and lies exposed above the pubis. The abdominal wall in children offers less protection because the rectus is less developed.
The rectus abdominis muscle is divided into two segments by the linea alba. It is segmented by tendinous intersections, which can create the appearance of a "six-pack" when body fat is low. The rectus abdominis makes up the top layer of the abdominal muscles, commonly referred to as the "six-pack".
Heat Therapy: Muscle Relaxation and Pain Relief
You may want to see also
Frequently asked questions
The bladder is a hollow, spherical-shaped organ that holds urine. It is the largest organ in the urinary tract when full.
The bladder wall contains specialised smooth muscle, known as detrusor muscle. The bladder neck is a narrow group of muscles that connect to the urethra.
The detrusor muscle contracts during urination to push urine out of the bladder and into the urethra. It relaxes to allow the storage of urine in the bladder.
The urethra is enveloped by urethral sphincter muscles which control the flow of urine when they contract. The external urethral sphincter is under voluntary control.
