The Peen

Question 1

Describe the descent of the testicles. (4)

Answer 1

They descend through the abdominal cavity taking some of the peritoneum with them, leaving the tunica vaginalis.
Their descent is guided by the gubernaculum, and the abdominal wall forms the spermatic fascia.

Question 2

Describe hydrocoele. (2)

Answer 2

Tunica vaginalis can fill with excess fluid. Confirmed with transillumination of the testicle (technically).

Question 3

Describe the vascular supply to the testicle. (5)

Answer 3

Arterial - testicular arteries arise from the AA.
Venous - pampiniform plexus surrounds the testicular artery to cool it for spermatogenesis. Right testicular vein - IVC, left - left renal vein - IVC.
Lymphatic drainage - scrotum is inguinal, testes are para-aortic.

Question 4

Describe testicular torsion. Explain why it is an emergency. (3)

Answer 4

When one testicle rotates on the spermatic cord. Initially there is venous drainage occlusion - swelling - arterial occlusion - necrosis. Threatens fertility and life.

Question 5

List the:
Layers of the spermatic cord
Nerves in the spermatic cord
Arteries
Veins
Lymphatics and other structures.

Answer 5

External fascia, cremasteric fascia, internal fascia.
Cremasteric nerve, sympathetic nerve to Vas, (external to spermatic cord) iliolingual nerve.
Cremasteric artery to fascia and muscle, testicular artery, artery to Vas Deferens.
Cremasteric vein, pampiniform plexus, vein to Vas Deferens.
Vas Deferens surrounded by lymphatics.

Question 6

Describe the relationship between the Vas Deferens and the ureter. (1)

Answer 6

Water under the bridge - ureter under Vas.

Question 7

Describe the structure of the prostate. (5)

Answer 7

The prostate is where the ejaculatory duct combines with the prostatic urethra to form the penile urethra.
Two central regions - transition (where the urethra flows) and central (ejaculatory duct).
Two peripheral regions - anterior region and peripheral (posterior) region.

Question 8

Describe which portions of the prostate are affected by anthology. (2)

Answer 8

BPH - transitional zone.

CaP - peripheral zone.

Question 9

Describe the components of ejaculation. (4)

Describe the functions of each fluid. (4)

Answer 9

Seminal vesicles - 65% - alkaline fluid containing fructose, prostaglandins and clotting factors.
Prostate - 25% - proteolytic enzymes.
Cowper’s or Bulborethral glands - 1% - lubricating mucus.
Testicular fluid - 10% - contains sperm.

Question 10

Describe the functions of the penis. (4)

Answer 10

Expulsion of urine via urethras.
Deposition of sperm in female genital tract.
Removal of competitors sperm.
Attraction of mates - standing while erect means good CV fitness.

Question 11

Describe the initiation of an erection. (3)

Answer 11

Vasodilation of the penile arteries, and compression of the veins initiated by the parasympathetic NS.

Question 12

Describe the termination of an erection. (2)

Answer 12

Vasoconstriction, and ejaculation are sympathetic.

Question 13

Explain the function of tunica albuginea. (2)

Answer 13

Collagen sheaths arranged at 90 degrees to make the penis cylindrical.

Question 14

Describe the anchoring of the penis. (2)

Answer 14

Penis is anchored to bone by suspensory ligaments. They dictate the flaccid penis length.

Question 15

Describe the vascular supply to the penis (1).

Answer 15

Branches of the pudendal artery and vein.

Question 16

Explain the differences between Sertoli and Leydig cells. (4)

Answer 16

Sertoli cells - line the seminiferous tubules and support the maturation of sperm.
Laydig cells - filled with SER and exist in the interstitium between the seminiferous tubules. Sex hormones derived from cholesterol are produced here eg testosterone.

Question 17

Describe the tissues of the penis. (4)

Answer 17

Two ET eyes of corpus cavenosum.
Chin of ET is corpus spongiosum.
Mouth of ET is the spongy or penile urethra
Outer border is the tunica albuginea.