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Bladder 101

Understanding Your Bladder

Your bladder is a hollow, balloon-shaped organ made mainly of muscle. It stores urine, which is the liquid waste from your body made by your kidneys. The urine moves from the kidneys to the bladder through tubes called ureters. When it gets close to filled, your body sends a signal that you need to go to the bathroom. The bladder muscle then squeezes to help push the urine through the urethra out of your body.

A bladder has four layers:

  • Urothelium is a thin layer that covers the inside of your bladder
  • Lamina propria comes next, which is a layer of loose connective tissue
  • Covering that tissue is muscle
  • A layer of fat sits outside the muscle

When cancer is found, it’s 80% likely to be in the cells that line the inside of the bladder and non-invasive. It can either grow in finger-like projections toward the center of the bladder (papillary carcinoma) or flat tumors that stay in the bladder lining (flat carcinoma). The cancer becomes invasive if it grows from the lining into another layer of the bladder. Most invasive tumors do not advance past the second layer and rarely into the muscle tissue. If it does, the cancer is likely to spread further and become harder to treat.