Spermatogenesis And Male Infertility Flashcards
What chromosome contains the sex determining region?
The Y chromosome
Development of testis occurs from what?
Bipotential gland
What does the foetal testes secrete?
Testosterone and mullerian inhibiting factors
What are the two primitive genital tracts?
Wolffian
Mullerian
What causes development of female genital tract?
Müllerian ducts -> repro tract
Wolffian ducts degenerate
What causes male repro tract to develop?
Wolffian ducts -> repro tract
Müllerian ducts degenerate
What is androgen insensitivity syndrome?
Testicular feminisation
Genetics of androgen insensitivity syndrome?
X linked recessive
46 XY
What happens in androgen insensitivity syndrome?
Androgen induction of wolffian duct doesn’t occur but mullerian inhibition does occur.
Testis develop but don’t descend.
Born phenotypically with female external genitalia - absence of ovaries and uterus
When does androgen insensitivity syndrome tend to present?
At puberty with primary amenorrhea and lack of public hair
How do the testes adapt to external temperature?
Nervous reflexes trigger dartos muscle contraction in scrotal sac to lower/ raise testes according to external temp
What is cryptorchidism?
Undescended testes
Management of cryptorchidism?
Orchidopexy before age of 14 to reduce risk of testicular germ cell cancer .
If an adult, consider orchidectomy
Function of the testis?
Spermatogenesis (seminiferous tubules)
Production of testosterone (leydig cells)
What do Sertoli cells do?
Form blood- testis barrier Provide nutrients for developing cells Phagocytosis Secrete seminiferous tubule fluid Secrete androgen binding globulin Secrete inhibit and activin hormones
Where is GnRH secreted from?
Hypothalamus, every 2-3 hours
What does GnRH do?
Stimulates anterior pituitary to produce LH and FSH
Where are LH and FSH secreted from?
Anterior pituitary
What does LH do?
Acts on Leydig cells, regulating testosterone secretion
What does FSH do?
Acts on Sertoli cells to enhance spermatogensis
Where is testosterone produced ?
In leydig cells
What is testosterone derived from?
Cholesterol
Where is inhibin and activin produced?
Sertoli cells
After ejaculation, what do spermatozoa do?
Chemo attraction to oocyte and bind to zone pellucida of oocyte
Acrosome reaction
Hyper activated motility
Penetration and fusion with oocyte membrane
Zonal reaction
Function of epididymis and vas deferens?
Exit route from testis to urethra
Concentrate and store sperm
Site for sperm maturation
Function of seminal vesicles?
Produce semen into ejaculatory duct
Secrete fibrinogen
Function of prostate gland?
Produces alkaline fluid - neutralises vaginal acidity
Produces clotting enzymes to clot semen within female
Function of bulbourethral gland?
Secretes mucous to act as a lubricant
Route of sperm?
Testes Epididymis Vas deferens Ejaculatory duct Urethra
Most common cause of male infertility?
Idiopathic
Obstructive causes of Male infertility?
CF
Vasectomy
Infection
Congenital causes of male infertility?
Cryptorchidism
Infective non obstructive cause of male infertility?
Mumps orchitis
Genetic non obstructive cause of male infertility?
Chromosomal- kleinfelters, micro deletions of Y chromosome, robertsonian translocation
Endocrine causes of non obstructive infertility?
Pituitary- Acromegaly, customs, hyperprotlactinaemia
Hypothalamic- Kallmans, anorexia, tumours
Thyroid- hyper/hypothyroidism
Diabetes
CAH
Androgen insensitivity
Steroid abuse
What is the normal testicular volume of an adult?
12-25ml
How do you measure testicular volume?
Orchidometer
What is involved in an endocrine profile for infertility?
LH FSH testosterone Prolactin TSH
Findings if obstructive cause of infertility?
Normal testicular volume
Normal secondary sexual characteristics
Vas deferens may be absent
Normal LH, FSH, testosterone
Findings if non-obstructive cause of infertility?
Low testicular volume
Reduce secondary sexual characteristics
Vas deferens present
High LH, FSH and low testosterone
