UG Development 4

Question 1

What happens to the genital tubercle and labioscrotal folds in the male and female?

Answer 1

• Male - genital tubercle becomes the penis and labioscrotal folds become the scrotum
• Female - genital tubercle becomes the clitoris and labioscrotal folds become the labia majora

Question 2

What are the origins of the penile urethra?

Answer 2

• Ventral fusion of the phallic part of the UG sinus
  
  • invaginates in the ventral surface of genital tubercle
  • UG folds incorporated into ventral surface
• Epithelial invagination of the tip of the penis
  
  • forms the navicular fossa

Question 3

In the female what happens to the urogenital sinus and folds?

Answer 3

• Lower UG sinus becomes:
  
  • urethra
  • vestibule
  • greater vestibular glands
  • paraurethral glands
• Urogenital folds become the labia minora

Question 4

What happens in hypospadius?

Answer 4

• A condition in the newborn where the penile urethra is open to the ventral surface of the penis
• Occurs if the two primordia of the penile urethra do not join

Question 5

How do fistulas/cysts/sinuses form?

Answer 5

• Improper division of the cloaca results in fistulas:
  
  • Female - between rectum and:
    
    • perineum
    • vestibule
    • vagina
  • Male - between rectum and:
    
    • perineum
    • urethra
    • bladder
• Cysts, sinus, fistulas of the allantois if it fails to fully become the urachus

Question 6

How do Gartner cysts form?

Answer 6

• From the improper closure of the mesonephric ducts (Gartner ducts)
• Paramesonephric duct cysts are the equivalent in males