Male Genitalia

Question 1

Describe testes descent during development

Answer 1

Testes descend from the posterior abdominal wall towards the scrotum

Gubernaculum guides the testes down

Testes evaginate the abdominal wall - creates fascial layers that surround the testes

Question 2

Where does spermatogenesis occur

Answer 2

Seminiferous tubules

Question 3

Describe the route of sperm from the seminiferous tubule to the vas deferens

Answer 3

Sperm are released into lumen of seminiferous tubule

Sperm drain into straight tubule -> rete testis -> efferent ductules -> epididymis

Then pass through the epididymis into the vas deferens

Question 4

What surrounds the seminiferous tubules

Answer 4

Tunica albuginea

Question 5

What surrounds the testis and what is it formed by

Answer 5

Tunica vaginalis

Formed by the peritoneum during the testes descent

Question 6

What cells are found in the testes, where are they found and what do they do

Answer 6

Sertoli - line seminiferous tubules. Support sperm maturation

Leydig - found in intersitium. Involved in sex hormone metabolism

Question 7

What prevents testicles swapping sides

Answer 7

Scrotal septum

Question 8

Describe the testicular blood supply

Answer 8

Testicular arteries come directly off the aorta

Testicular veins form pampiniform plexuses around testicular arteries

Left testicular vein drains into renal vein

Right testicular vein drains into IVC

Question 9

Where do the testicular lymphatics drain and why is this important

Answer 9

Drain into the para-aortic lymph nodes

Important as metastases will be found here

Question 10

Where do scrotal lymphatics drain

Answer 10

Inguinal lymph nodes

Question 11

What are the three facial layers of the spermatic cord and what are they formed by

Answer 11

External spermatic fascia - external oblique muscle

Cremasteric fascia - internal oblique muscle

Internal spermatic fascia - transverse abdominis

Question 12

What are the three arteries found in the spermatic cord

Answer 12

Testicular artery

Artery to vas deferens

Cremasteric artery

Question 13

What are the three veins found in the spermatic cord

Answer 13

Pampiniform pleuxs

Vein to vas deferens

Cremasteric vein

Question 14

What are the three nerves in the spermatic cord

Answer 14

Nerve to vas deferens

Cremasteric nerve

Ilioinguinal nerve

Question 15

What is the cremasteric reflex

Answer 15

Reflex where if the inner thigh is stroked, the ipsilateral testicle will rise up towards the pelvis

Question 16

What other three structures are found within the spermatic cord

Answer 16

Vas (ductus) deferens

Lymphatic drainage

Processus vaginalis/ patent processus vaginalis

Question 17

What structures produce a substance that forms seminal fluid/sperm - include percentage

Answer 17

Epididymis and testes - 10%

Seminal vessels - 65%

Prostate gland - 25%

Bulbourethral glands - <1%

Question 18

Describe the flow of seminal fluid from vas deferens to the urethra

Answer 18

Seminal fluid passes through vas deferens and combines with tubes and fluid from seminal vessels to form the ejaculatory duct

The duct then enters the central zone of the prostate where it flows into the urethra

Seminal fluid from the prostate is secreted into the duct here

Fluid then continues along the urethra to be ejected

Question 19

What is found in fluid produced by the seminal vessels

Answer 19

Fructose-based alkaline fluid

Question 20

What is found in fluid produced by the prostate

Answer 20

Milky secretion which is slightly acidic and contains proteolytic enzymes

Question 21

What is the function of fluid produced by the bulbourethral glands

Answer 21

Decrease friction

Question 22

How is the penis attached to the body

Answer 22

Corpus cavernosum attachs to pubic bones/pubic arch

Two suspensory ligaments support the penis at its base

Question 23

What surrounds the corpus spongiosum and corpus cavernosum. What is its function

Answer 23

The tunica albuginea

It maintains the cylindrical shape during an erection - collagen fibres are arranged at right angles to each other

Question 24

What is the blood supply to the penis

Answer 24

Pudendal arteries supply perineal arteries which then supply:

• Dorsal arteries
• Cavernous artery
• Bulbourethral artery
• Circumflex artery

Question 25

What are the sections of the urethra

Answer 25

Prostatic urethra

Membranous urethra

Spongy urethra

Question 26

How does an erection occur

Answer 26

Vasodilation of penile arterioles and compression of veins results in blood being pooled in the corpus cavernosum -> erection