Human Anatomy and Physiology - N. I. Fedyukovich 2003

Internal Organs
Urogenital System
Ureters

The Ureter is a paired organ that transports urine from the Kidney to the Urinary Bladder. It is a tubular Structure with a diameter of 6—8 mm and a length of 30—35 cm. It is divided into abdominal, pelvic, and intramural parts.

The abdominal part lies retroperitoneally, running along the Medial surface of the psoas major Muscle toward the lesser pelvis. The right ureter originates at the level of the descending part of the duodenum, while the left originates at the duodenojejunal flexure.

The pelvic part of the ureter begins at the pelvic brim, running anteriorly, medially, and downward to the Base of the urinary bladder.

Within the cavity of the lesser pelvis, each ureter lies anterior to the internal iliac artery. In females, the pelvic part of the ureter passes posterior to the Ovary, then curves laterally around the cervix and lies between the anterior vaginal wall and the urinary bladder. In males, the pelvic part lies lateral to the vas deferens, then crosses it and enters the urinary bladder. The lumen of the ureter is slightly narrowed in its pelvic part.

The terminal segment (1.5—2.0 mm long) of the pelvic part of the ureter runs obliquely through the wall of the urinary bladder and is known as the intramural part.

The ureter has three dilations (lumbar, pelvic, and just before entering the urinary bladder) and three constrictions (at the junction with the renal pelvis, at the transition from the abdominal to the pelvic part, and before opening into the urinary bladder).

The wall of the ureter consists of three layers. The inner mucosa is lined with transitional epithelium and has deep longitudinal folds. The middle muscular layer consists of an inner longitudinal and an outer circular layer in the upper part, and in the lower part, of inner and outer longitudinal layers and a middle circular layer. Externally, the ureter is covered by an adventitial coat. This structure ensures the unobstructed passage of urine from the kidney to the urinary bladder.