The bladder or the urinary bladder is a muscular sac. It is a hollow organ located at the base of the pelvis in the lower abdominal area. This expandable sac stores urine that is released from the kidneys. The urine is later secreted through the urethra out of the body. When empty, the bladder folds and when urine enters, it expands. Urine is released into the urethra with the expansion and contraction of the bladder. A normal adult human bladder can accommodate up to 24 ounces of urine. Internal muscles of the bladder contract in order to prevent involuntary leakage of urine. The nerves connected to the bladder play an important role to prevent urinary incontinence. These nerves are connected to the central nervous system. Conditions of the bladder include bladder infection, inflammation of the bladder, formation of cysts (cystitis), urinary incontinence, and bladder cancer. Symptoms of bladder diseases manifest in the form of frequent urination, change in color if urine, pain during urination, overactive bladder, and urinary retention. Diagnosis of the conditions are made using tests like urine tests, x-rays, ultrasound, cystoscopy and other tests. Treatment depends upon the underlying condition.