Male Reproductive System

Question 1

Describe the perineal membrane in male.

Answer 1

• Superficial to pelvic diaphragm
• Covers urogenital triangle
• Opening for urethra

Question 2

Describe the deep perineal pouch in males.

Answer 2

• Space above the perineal membrane
• Contains skeletal muscle that form sphincters around urethra, glands, and neurovascular structures that supply the penis

Question 3

Describe testes.

Answer 3

• Divided into approximately 250 lobules by connective tissue septa
• Each lobule contains 3-10 seminiferous tubules
• Each tubules forms a highly convoluted loop within lobule
• Tubules end as straight tubule (tubulus erectus) at mediastinum
• Connected to rete testis (anastomosing channel system)
• Tunica vaginalis: during descent, extension of abdominal peritoneum
• Tunica albuginea: dense connective tissue capsule

Question 4

Sperms only becomes motile in the ___________.

Answer 4

Epididymis

Question 5

Describe the process of testicular descent.

Answer 5

• Gonadal development occurs along posterior abdominal wall
• Testes descend toward the inguinal canal by 7 months gestation
• Through inguinal canal into scrotum just before birth
• Drags blood vessels, nerves, duct system (vas deferens) and layers of abdominal wall into scrotum

Question 6

Describe the epididymis.

Answer 6

• About 5m long, highly coiled tube
• Consist of caput (head), corpus (body), and caudal (tail) segments
• Surrounded by smooth muscle cells
• Storage and maturation of sperm (acquire ability to move)

Question 7

Describe the vas deferens.

Answer 7

• Muscular duct (smooth muscle wall) which transports spermazoa to ejaculatory duct
• Part of spermatic cord
• Ejaculation mediated by sympathetic nervous system

Question 8

Describe the seminal vesicle.

Answer 8

• Posterior surface of bladder
• Ducts of seminal vesicles join vas deferens to form ejaculatory duct, which empties into prostatic urethra
• Contribute to volume of semen
• Secretes alkaline, viscous fluid (55-61% of seminal fluid) – neutralization of acidic female reproductive tract environment
• Contributes to sperm motility and viability

Question 9

Describe the prostate

Answer 9

• Inferior to the bladder
• Anterior to the rectum
• Superior to the perineal membrane
• Surrounds the urethra
• Function
  
  • Secretion (30-35% of semen): watery liquid containing zinc, citric acid, prostaglandins and proteolytic enzymes
  • One component: prostate-specific antigen – liquefies semen – help movement of sperm
  • Muscle help moves seminal fluid into urethra
  • Acts as valve: ensure the right fluid flows at the right time – urination or ejaculation

Question 10

Describe disorders of the prostate.

Answer 10

• Benign Prostatic Hypertrophy
  
  • Occurs in most elderly men
  • Hypertrophy of central prostate
  • Compresses urethra and can eventually block it entirely
  • DRE reveals “bulky” prostate
• Prostate cancer
  
  • Common malignancy in men
  • Affects entire thickness of prostate
  • Diagnosed by DRE (feels “rock hard” and blood tests”
  • Can be treated by radiotherapy, chemotherapy, or removal.

Question 11

Describe the bulbourethral glands.

Answer 11

• Paired, pea-shaped
• In deep perineal pouch
• Duct opens into spongy urethra
• Mucous type secretion into spongy urethra
• Forms pre-ejaculate

Question 12

Mention the peritoneal pouch on males.

Answer 12

Question 13

Describe the external genitalia of males.

Answer 13

• Erectile tissue covered by skin
• Body of penis is pendulous and entirely surrounded by skin
• Scrotum = homologue of labia majora – skin fused in midline (raphe)
  
  • Testes descend into the pouch
• Skin over glans penis = prepuce is open anteriorly and attached to glans at the frenulum

Question 14

Describe the penis.

Answer 14

• Perineal membrane and pubic arch = attachment for roots of penis
• Erectile tissues: two corpora cavernosa and a single corpus spongiosum
• Corpus spongiosum expands distally to form glans penis
• Urethra pierces perineal membrane, enters corpus spongiosum, and opens at glans penis

Question 15

Explain how erection occurs.

Answer 15

• Erection is mediated by parasympathetic nervous system, which relaxes arteries in penis allowing blood to fill erectile tissues
• Ischiocavernosus and Bulbospongiosus muscle move blood from root into body of penis and constrict venous drainage

Question 16

Recall the development of male external genitalia

Answer 16