Everything about Ureter totally explained
In human
anatomy, the
ureters are muscular ducts that propel
urine from the
kidneys to the
urinary bladder. In the adult, the ureters are usually 25-30cm (10-12 inches)long.
In humans, the ureters arise from the renal pelvis on the medial aspect of each kidney before descending towards the bladder on the front of the
psoas major muscle. The ureters cross the pelvic brim near the bifurcation of the iliac arteries (which they run over). This "pelviureteric junction" is a common site for the impaction of
kidney stones (the other being the ureterovesical valve). The ureters run posteroinferiorly on the lateral walls of the pelvis. They then curve anteriormedially to enter the bladder through the back, at the vesicoureteric junction, running within the wall of the bladder for a few centimeters. The backflow of urine is prevented by valves known as ureterovesical valves, pressure from the filling of the bladder, and the tone of the muscle in the bladder wall.
In the female, the ureters pass through the
mesometrium on the way to the
urinary bladder.
Histology
The ureter has a diameter of about 3 millimeters, and the lumen is star-shaped. Like the bladder, it's lined with
transitional epithelium, and contains layers of smooth muscle, thereby being under autonomic control.
The epithelial cells of the ureter are stratified (in many layers), are normally round in shape but become squamous (flat) when stretched. The
lamina propria is thick and elastic (as it's important that it's impermeable).
There are two
spiral layers of smooth muscle in the ureter wall, an inner loose spiral, and an outer tight spiral. The inner loose spiral is sometimes described as
longitudinal, and the outer as
circular, (this is the opposite to the situation in the
gastrointestinal tract). The distal third of the ureter contains another layer of outer longitudinal muscle.
The adventitia of the ureter, like elsewhere is composed of
fibrous connective tissue, that binds it to adjacent tissues.
Diseases and disorders
Medical problems that can affect the ureter include:
Further Information
Get more info on 'Ureter'.
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