The urinary tract system (Keep Your Bladder Health) comprises of organs that are responsible for production and excretion of nitrogenous waste products that are produced by the body as a result of biological and metabolic processes. The urinary system is composed of:
- Kidneys – On either side of the posterior abdominal wall (in the lumbar quadrant of abdomen)
- A Muscular Bag – Urinary bladder (Bladder Voiding Dysfunction) that is responsible for storing the urine. Urinary bladder is a pelvic organ (unless it is full). The capacity of bladder can be as high as 600 to 800 ml of urine; however, it is recommended to void at intervals.
- Tubular Structures – Ureters that connects the kidneys with urinary bladder
- Urethra – The terminal end of urinary bladder that communicates with the exterior and helps the human body in getting rid of excess water, nitrogenous waste products and unnecessary electrolytes
Functions Of The Ureter
Ureter is a tube that carries the urine from the kidney to the bladder. The muscular walls of ureter are thick and allow continuous or uninterrupted flow of urine under the influence of gravity. In addition, the muscular walls of ureter generates wave of contractions (also known as peristalsis) that are similar in character to gastrointestinal (Gastrointestinal Wiki Page) peristalsis to propel the free flow of urine.
There are two ureters that originate from each kidney. Both ureters enter the bladder at an angle in order to prevent the back-flow or reflux of urine into the ureter, upon the contraction of bladder.
Structure Of The Ureter
- The length of ureter is 25- 30 cm (or 10-12 in)
- It begins at the level of renal pelvis (the funnel shaped peripheral part of kidneys that also allow entry and exit to major vessels and nerves to the kidney).
Histological, Ureter Comprises Three Layers Of Cells
- The innermost layer is referred to as the mucous coat. It is continuous with the lining of renal tubules from above and to the bladder from below.
- The middle layers is the muscular coat that comprises of large fibers of smooth muscles (this layer allow partial expansion in case of a mechanical obstruction).
- The outermost layer is the fibrous coat that comprises primarily of connective tissues.
Natural Constrictions Of The Ureter
The diameter is not uniform throughout the length of ureter. There are three anatomical sites of constriction:
- Site where ureters exits through the renal pelvis
- At pelvic brim (when ureter enters the pelvic cavity – just where the common iliac arteries bifurcate into internal iliac and external iliac arteries
- Ureteropelvic junction- at the point of entry of ureter in the urinary bladder (Antibiotics for Urinary Tract Infections).
Anatomical Structures or Landmarks of the Ureter
Knowing major nerves, vessels and muscles that are present in the proximity of ureter may help the clinician in making sensible and practical decisions at the time of surgical procedures (Bladder Procedures); however, every individual should know about the anatomy and physiology of ureter in order to prevent injuries and accidents involving these structures. Psoas major, pelvic brim, common iliac vessels and fundus of the urinary bladder are major structures that are associated with ureter and should be protected from injuries via protective shield during active/ contact sports.
Any injury (Urethral Injury Early Treatments), trauma, malignancy or pressure (due to impaction of renal stones) can affect the integrity of ureters and may lead to infections (Bladder Infection Causes | Catheter), diseases, metabolic imbalance, electrolyte imbalance and other issues that can compromise all major organs and systems.
The urinary system primarily functions to regulate internal biochemical environment of the body by removing unwanted substances from the systemic circulation.
Spronck, B., Merken, J. J., Reesink, K. D., Kroon, W., & Delhaas, T. (2014). Ureter smooth muscle cell orientation in rat is predominantly longitudinal. PloS one, 9(1), e86207.