- As it fills with urine, the muscular wall of the bladder stretches and the bladder gets larger.
- When the bladder reaches its capacity of urine, the bladder wall contracts, although adults have voluntary control over the timing of this contraction. At the same time, a urinary control muscle (sphincter) in the urethra relaxes. The urine is then expelled from the bladder.
- The urine flows through a narrow tube called the urethra and leaves the body. This process is called urination, or micturition.
Bladder cancers are most likely to spread to neighboring organs and lymph nodes prior to spreading through the blood stream to the lungs, liver, bones, or other organs.
Symptoms include:
- Blood in your urine
- A frequent urge to urinate
- Pain when you urinate
- Low back pain