Histology of the Male Reproductive System 2

Question 1

What are the origins of the scrotum and what makes up the scrotum?

Answer 1

• Sack of superficial body wall
• Epidermis
• Special muscles
  
  • Dartos muscle/fascia - smooth muscle that corrugates skin of scrotum when testes are elevated
    
    • located in the very thin, superficial fascia layer
  • Cremaster muscle - striated muscle that elevates the testes for temperature regulation
    
    • derived from internal oblique muscle
    • innervated by genitofemoral nerve from lumbar plexus

Question 2

What is the testis derived from and what are the endocrine and exocrine functions of the testis?

Answer 2

• Derived from intermediate mesoderm of the gastrula
• Exocrine product - sperm
• Endocrine hormone - testosterone

Question 3

What are the major components of the testis?

Answer 3

• Tunica albuginea - dense connective tissue capsule
  
  • septae extend inward from the capsule
    
    • separates lubles, each containing 1-4 seminiferous tubules 30-70 cm long
• Interstitial space - very vascular
  
  • interstitial Leydig cells - testosterone production
  • fenestrated capillaries
  • connective tissues
  • lymphatic capillaries

Question 4

What are the seminiferous tubules and what are they derived from?

Answer 4

• sperm-producing structures that fill the substance of the testes
• derived from primary sex cords in the embryonic gonad
• highly coiled, about 200 microns in diameter and 1/3 mile in length in total
• specialized, stratified epithelium with Sertoli cells that surround germ cells in various stages of spermatogenesis

Question 5

Describe the tunica propria of the seminiferous tubules.

Answer 5

• External to basal lamina
• Consists of 3-5 layers of contractile myoid cells and collagen fibrils produced by the myoid cells

Question 6

Describe the histology of the prostate gland.

Answer 6

• Glandular epithelium is simple columnar, but can be cuboidal or pseudostratified
• Lumen of the gland soften contain prostatic concretions, a diagnostic identifier of the prostate gland in micrographs
  
  • appear as concentric lamellar structures that are often calcified
• Divided into several zones
  
  • central zone - surrounds ejaculatory ducts, 25% of the gland, and cells here are resistant to cancer
  • peripheral zone - surrounds central zone laterally and posteriorly, makes up 70% of the gland, and most prostate gancers develop here
  • periurethral and tranzitional zones - surround prostatic urethra, glands can grow and lead to benign prostatic hyperplasia and compress urethra

Question 7

What are the bulbourethral (Cowper’s) glands?

Answer 7

• Mucous gland dquivalents of the greater vestibular glands in the female
• Lubricate the urethra prior to ejaculation

Question 8

Describe the structure of the penis.

Answer 8

• Swelling of somatopleure
• Corpus cavernosa is the main erectile tissue
• Corpus spongiosum contains the urethra
• Erectile tissue consists of vascular spaces in both of the above that fill with blood from dilation of the helicine arteries in resposne to parasympathetic stimulation
• Urethra is within the corpus spongiosum on the ventral side