Spermatogenesis and Male Infertility Flashcards
What determines the development of the internal reproductive tract in the embryo?
SRY on Y chromosome result in the development of testes, and the degeneration of the mullerian ducts
What will the foetal testes secrete?
Testosterone
AMH
What are the 2 primitive genital tracts?
Wolffian
Mullerian
What duct is present in males?
Wolffian
What duct is present in females?
Mullerian
When can you distinguish sex on a USS?
Week 16
What is androgen insensitivity syndrome (testicular feminisation)?
Congenital insensitivity to androgens
Testis develop but do not descend
Androgen induction of wolffian duct does not occur, but mullerian inhibition occurs
What internal sex organs will those with testicular feminisation have?
Externally female genitalia
Absence of uterus and ovaries
Short vagina
How will those with androgen sensitivity present?
Puberty with primary amenorrhoea and a lack of pubic hair
What is the function of the testis?
Spermatogenesis (seminiferous tubules)
Production of testosterone (leydig cells)
What covers the testis?
Double layer of tunical vaginalis
White fibrous tunica albingia
Why is the descent of the testis important?
Lower temp outside body to facilitate spermatogenesis
Nervous reflex triggers dartos muscle contraction in scrotal sac to lower/ raise testes according to the external temp
How common is cryptorchidism?
1:25
When should an orchiopexy be performed in cryptorchidism?
By 12 months due to strong assoc with azoospermia
12 years to minimize risk of testicular germ cell ca
If undescended as adult - consider orchidectomy
What are the venous drainage of the testes?
Left testicular joins left renal
Right drains directly to IVC
What gonadotropin drives sertoli cell function?
FSH
What gonadotropin drives testosterone production?
LH - leydig cells
What is present in the head of a sperm?
Acrosome - enzymes required for penetration of ovum
Nucleus
What is present in the midpiece of the sperm?
Mitochondria
What is present in the tail of the sperm?
Microtubules
What is the function of the sertoli cells?
Blood-testes barrier Nutrientes Phagocytosis Secrete seminiferous tubule fluid Secrete ABG Secretes inhibin and activin
Describe the GnRH release in men?
Every 2-3 hours
Begins age 8-12
What is testosterone?
Steroid hormone derived from cholesterol
Secreted into blood and seminiferous tubules for sperm production
Effect of testosterone before birth?
Masculinises reproductive tract and promotes descent of testes and generation of external genitalia