Ureters – posterior to vas deferens (in female, they pass posterior to cardial ligament and uterine vessels)

Urinary Bladder – lies within extraperitoneal space and rests on pelvic diaphragm; funnels into the prostate gland

• anterior surface of urinary bladder defines the posterior limit of a potential space, the retropubic space of Retzius
• puboprostatic ligaments provide attachment to the bony pelvis, so pelvic fractures can disrupt urethra and bladder
• posterior bladder contacts the rectovesical pouch, rectovesical fascia of Denonvilliers’, and the seminal vesicles
• Detrussor muscle – smooth muscle wall of urinary bladder, composed of transitional epithelium; high compliance
• Innervation – pelvic splanchnic nerve (S2-S4 parasympathetic) Þ activates non-cardiac smooth muscle
• hypogastric plexus (T12-L3 sympathetic) Þ inhibits non-cardiac smooth muscle; also senses bladder fullness
• Micturition – coordinated reflex emptying bladder through urethra; initiated by stretching of detrussor muscle
• spinal reflex causes coordinated contraction of detrussor and relaxation of urinary sphincter
• under control of pontine micturition center, suppressed by cerebrum
• Pathology – Hutch Diverticulum ("Mickey Mouse Bladder") – deformity of urogenital system leading to two bladders

Urethra – divided into prostatic, membranous and anterior (bulbous and pendulous) portions

• (1) Prostatic urethra – receive fluid from prostatic ducts during ejaculation
• prostatic utricle lies within the venumontanum (colliculus seminalis)
• (2) Membranous urethra – transverses the urogenital diaphragm; most common site of rupture after pelvic fractures
• (3) Anterior Urethra – bulbous and penile urethra, most common site of urethral stricture disease
• bulbourethral glands of Cowper enter just below urogenital diaphragm
• penile urethra enlarges at distal end, forming fossa navicularis
• Pathology
• bulbous urethra is a common site of gonorrhea infection and stricture, causing backflow of urine to kidney
• epispadias Þ non-closure of dorsal surface of penis; hypospadias Þ non-closure of ventral surface of penis

• prostate fluid composes 20% of ejaculate and aids in sperm transport
• androgens cause development from budding of urogenital sinus
• glandular epithelium secretes prostate specific antigen (PSA), an enzyme that lyses seminal coagulum
• PSA is a marker for prostate cancer
• stroma contains alpha-1 adrenergic receptors that regulate smooth muscle tone of the prostate
• lies between bladder and UG diaphragm anterior to rectum; anterior surface is adj. to rectopubic space of Retzius – 3 zones:
• (1) Peripheral zone – 70% of prostate cancer found here
• (2) Transition zone – common location of benign prostate hyperplasia (BPH)
• (3) Central zone – periurethral area
• Santorini’s venous plexus surrounds prostate; drains prostate and inferior bladder and empties into hypogastric veins
• this can rupture during surgery or trauma
• digital rectal exam allows for palpitation of the posterior zone of the prostate
• pudendal nerve and artery for the neurovascular bundle of the penis and lies posterolateral to the prostate
• Pathology – Mullarian Duct Cysts (Utricle) Þ obstructs ejaculatory duct when dilated

• paired tubes derived from Wolffian duct – contribute 40% of ejaculatory fluid (rich in fructose)
• may be palpable in digital rectal exam
• Pathology – seminal vasculitis/infection results in hematosemia – little clinical significance

Testes – house germ cells (produce spermatogonia), stromal (Leydig) cells (androgen production), and Sertoli cells

• normally firm and 4.5 cm x 3 cm x 3 cm; position in scrotum allows for reduced temperature and optimum spermatogenesis
• form in abdominal gonadal ridge under influence of androgens and Mullarian Inhibitory Factor (MIF) – descend to scrotum
• MIF produced by testis acts mostly on ipsilateral side
• Blood Supply – testicular artery from aorta, collateral supply from vas deferens and cremaster arteries
• right gonadal vein empties into inferior vena cava; left gonadal vein empties into renal vein
• Innervation – T10-L2 via splanchnic nerves results in referred pain to lower back
• testes tubules (seminiferous ducts): 300 lobules in each testis containing 1 to 4 seminiferous tubules, each 75 cm long
• seminiferous tubules lead into about 25 straight tubules that coalesce in the rete testes to for 15 to 20 efferent ductules which penetrate the tunica albuginea and enter the epididymis
• normal testis is 4.5 cm x 3 cm x 3 cm in size and firm
• 7 layers of scrotum – skin, dartos, ext. spermatic fascia, cremaster, int. spermatic fascia, peritoneum, tunica vaginalis
• Pathology
• failure of descent – occurs in 1% of boys by 1 year of age, leads to infertility and Ý rate of germ cell tumors
• variceles – dilations of pampinoform plexus, usu. above left testis (greater hydrostatic pressure in left gonadal vein)
• associated with infertility; can be corrected surgically
• testicular failure – often associated with small soft testes
• testicular torsion – infrequent (puberty); results in spasmodic contraction of the cremasteric muscle and abnormal gubernacular attachment of testis to scrotum
• produces cork-screw effect, which leads to ischemic necrosis within 4-6 hours
• tumors – metastases follow lymphatic drainage through spermatic cord to retroperitonium; intraaorto-caval nodes on right, peri-aortic nodes on left
• hernia/hydrocele – persistence of the process vaginalis (transversalis fascia) after testis descent leads to hydrocele

Epididymis and Vas Deferens – may enhance fertility of sperm

• Emission – parasympathetic "point" – thoracolumbar nerve
• Ejaculation – sympathetic "shoot" – from perineal branch of pudendal nerve (other factors also involved)
• neurovascular bundle Þ also involved in erection, located near prostate Þ may be damaged during prostate surgery

• Buck’s fascia separates penis from the body
• Pathology
• fractured penis – torn corporea; hematoma can leak into abdomen if Buck’s fascia is also damaged
• straddle injuries – damage to the inferior pudendal artery can lead to disruption of blood flow, resulting in priapism
• Pyronies Disease – scar in tunica albiginea causing penis to be bent superiorly
• atheroscloerosis of Pudendal (Alcock’s) Canal – normally houses pudendal artery which supplies the penis

Rectum – anus separated from urogenital system by elongation and folding of the cloaca