Ureter Anatomy and Function

Study Notes

Ureter

Muscular tube, 25-30 cm long and 3-4 mm in diameter.
Extends from kidneys to the urinary bladder.
Transports urine from kidneys to the bladder.
Urine movement:
- Peristaltic contractions (1-5/min).
- Hydrostatic pressure and gravity.
Ureter course in the abdomen:
- Starts at the hilum of the kidney, as a continuation of the renal pelvis.
- Descends retroperitoneally on the Psoas muscle.
- Crosses the bifurcation of the common iliac artery at the pelvic brim to enter the pelvis.
- Produces a kink as it crosses the pelvic brim.
Ureter course in the pelvis:
- Runs downward and backward on the lateral wall of the pelvis towards the ischial spine.
- Turns forward to enter the posterolateral angle of the bladder.
Gender differences:
- Male: crossed by the vas deferens superomedially near its termination.
- Female:
  - Passes behind the ovary.
  - Crosses medial to the origin of the uterine artery and below the broad ligament of the uterus.
  - Risk of injury during uterine artery ligation in hysterectomy procedures.
Relations of the right ureter:
- Anteriorly:
  - Second part of the duodenum.
  - Right gonadal vessels.
  - Right colic and ileocolic vessels.
- Posteriorly:
  - Right Psoas muscle.
  - Bifurcation of the right common iliac artery.
Relations of the left ureter:
- Anteriorly:
  - Left gonadal vessels.
  - Left colic vessels.
  - Sigmoid colon.
- Posteriorly:
  - Left Psoas muscle.
  - Bifurcation of the left common iliac artery.
- Medially: inferior mesenteric vein.
Constrictions of ureter:
- Potential sites of obstruction by ureteric stones.
- Occur at:
  - Ureteropelvic junction.
  - Pelvic brim.
  - Ureterovesical junction.
Peristaltic contractions ensure unidirectional flow of urine.

Urinary Bladder

Hollow muscular organ in the pelvic cavity.
Situated posterior to the pubic symphysis.
In adults:
- Completely in the pelvic cavity when empty.
- Extends into the abdominal cavity when full.
Lower level in females due to the absence of the prostate gland.
Shape:
- Pyramidal (apex, base, and 3 surfaces) or pear-shaped when empty.
- Apex:
  - Pointed anteriorly.
  - Behind the upper margin of the pubic symphysis.
  - Connected to the umbilicus by the median umbilical ligament.
  - Median umbilical ligament: remnant of the urachus.
  - Urachus: remnant of the allantois.
  - Allantois: duct that carries urine from the fetus's body to the umbilical cord.
- Base (Fundus):
  - Faces posteriorly.
  - Triangular in shape.
  - Superior angles joined by ureters.
  - Inferior angle (neck) gives rise to the urethra.
  - Superior part covered by peritoneum.
  - Structures on the bladder base:
    - Male:
      - Vasa deferentia pass medially to the seminal vesicles, separating the bladder from the rectum.
      - Retrovesical fascia and fat.
      - Rectovesical (retrovesical) pouch: peritoneal fold between the bladder and rectum, the lowest point in the abdomen.
    - Female:
      - Vagina posterior to the bladder, separating it from the rectum.
      - Rectouterine pouch: peritoneal fold between the uterus and rectum.
- Superior surface:
  - Separates the bladder from:
    - Male: coils of ileum and sigmoid colon.
    - Female: the body of the uterus.
  - Uterovesical pouch: peritoneal fold between the uterus and the superior surface of the bladder.
  - The bladder bulges upwards into the abdomen when full, becoming ovoid.
- Two inferolateral surfaces.
Internal structure:
- Folded into rugae when empty.
- Rugae disappear when full.
- Except over the internal surface of the base (trigone).
- Trigone:
  - Smooth mucous membrane adherent to the underlying muscular layer.
  - Superior angles: ureters, connected by the interureteric ridge.
  - Inferior angle: urethral orifice, protected by the internal urethral sphincter.
Innervation:
- Sympathetic: L1 and L2 ganglia of the sympathetic trunk.