Increased Urinary Frequency Anatomy
To better understand urinary frequency, it helps to understand the anatomy of the bladder and genitourinary system.
In an adult, the bladder can hold 10 to 20 ounces of urine--about as much liquid as in one can of soda. Urine is carried out of the body through the urethra, a tube at the bottom of the bladder.
As the bladder fills, it pushes against the rest of the organs in the abdomen. Urine empties from the bladder through the urethra. Muscles located in the base of the urethra control the flow of urine. During urination, these muscles relax, and urine is allowed to pass.
- Brubaker L, Chapple C, Coyne KS, Kopp Z. Patient-reported outcomes in overactive bladder: importance for determining clinical effectiveness of treatment. Urology. 2006 Aug;68(2 Suppl):3-8. 
- Czaja CA, Hooton TM. Update on acute uncomplicated urinary tract infection in women. Postgrad Med. 2006 Jun-Jul;119(1):39-45. 
- Hung MJ, Ho ES, Shen PS, Sun MJ, et al. Urgency is the core symptom of female overactive bladder syndrome, as demonstrated by a statistical analysis. J Urol. 2006 Aug;176(2):636-40. 
- Staskin DR. Overactive bladder in the elderly: a guide to pharmacological management. Drugs Aging. 2005;22(12):1013-28.