Male Infertility Flashcards
what determines the development of the testis from biopotential gonad
Sex determining region on the Y chromosome
testosterone and mullerian inhibiting factor cause the development of the male internal genital tract
what determines the female reproductive tracts
wolffian ducts degenerate
mullein ducts give rise to repro tract
how doest androgen insensitivity syndrome (testicular feminisation) occur
X linked recessive disorder
No androgens so male reproductive system does not develop
XY chromosomes so should be male
born phenogenically female with absence of uterus and ovaries with short vagina
commonly present at puberty with primary amenorrhoea and lack of pubic hair
where do testes develop in the foetus
abdominal cavity
when do testes descend into the scrotal sac
before birth
imports as there is a lower body temp outside to facilitate spermatogenesis
what is the name for undescended testes
Cryptorchidism
(usually would descend between 6-9 months of age_
what is orchidopexy and when should it be done
surgical descend of the testes
should be performed by 12 months because of strong association with infertility and risk of testicular germ cancer
what are the 3 main tubes in the penis
corpus cavernous corpus spongiosum (has urethra in it)
what cells are responsible for spermatogenesis
Sertoli cells
what is the blood-testes barrier
barrier formed by Sertoli cells
protects the sperm from antibody attack
provides suitable fluid composition which allow later stages of development of sperm
what are the functions of Sertoli cells
Form blood-testes barrier Provide nutrients Phagocytosis Secrete seminiferous fluid Secrete androgen binding globulin Secreted inhibit and activin hormones
what hormones control spermatogenesis
FSH and testosterone
what is gonadotrophin releasing hormone
decapeptide
released from hypothalamus in bursts
stimulates LH and FSH release from anterior pituitary
negative feedback control by testosterone
what does LH do
acts on leydig cells to regulate testosterone secretion
what does FSH do
acts on Sertoli cells to enhance spermatogenesis
regulated by negative feedback from inhibin
what hormone triggers LH and FSH release from the pituitary
GnRH - gonadotrophin-releasing hormone
what are the effects of testosterone
Before birth:
-masculinises repro tract and promotes testes descent
puberty:
- promotes puberty and male characteristics
adult:
-controls spermatogenesis, secondary sexual characteristics, libido, penile erection, aggressive behaviour
what are inhibit and activin
peptides secreted by Sertoli cells
feedback on FSH
(inhibit inhibits and avtivin stimulates)
after ejectulation, where does the sperm go
chemoattraction to oocyte
binds to zone pellucid
penetration and fusion with oocyte membrane
what is the function of the epididymis and vas deferent
exit route from testes to urethra
concentrates and stores sperm
site for sperm maturation
function of the seminal vesicles
produce semen into ejaculatory duct
supply fructose
secrete prostaglandins
secrete fibrinogen
function of the prostate gland
produces alkaline fluid
produces clotting enzymes to clot semen within female
function of bulbourethral glands
secrete mucus to act as lubricant
what is male infertility
infertility resulting from failure of sperm to normally fertilise the egg
usually associated with abnormalities in semen
causes of male infertility
Idiopathic
Obstructive
- cystic fibrosis
- vasectomy
- infection
non-obstructive
- congenital
- infection (mumps)
- iatrogenic (chemo/radio)
- genetic
- specific semen abnormality
- systemic disorder
- endocrine
what are some endocrine causes of male infertility
Pituitary tumours Hypthalmic causes Thyroid disorders Diabetes CAH Androgen insensitivity Steroid abuse (decreases testosterone)
how do you assess male infertility
see as couple
history (andrology history)
examination
investigations
how do you examine a male with infertility
General exam
- secondary sexual characteristics/presence of gynacomastia
genital exam:
- testicular volume
- presence of vas deferent and epididymis
- penis (urethral orifice)
- presence of any varicocele/other scrotal swelling
what is normal testicular volume pre-pubertal
1-3mls
what is normal testicular volume in adults
12-25mls
if below 5ml unlikely to be fertile
measure using an orchidometer
how do you analyse semen
look at: volume density (numbers of sperm) motility (what proportion are moving) progression (how well they move) morphology
what factors affect the result of semen analysis
Completeness of sample Period of abstinence Condition during transport Time between production and assessment Natural variations between samples Health of man 3 months before production
what further investigations can be done for male infertility
Repea semen analysis 6 weeks later
Endocrine profile
Chromosome analysis, cystic fibrosis screening
depending on results:
- biopsy
- scotal scan
what is obstructive infertility
normal volume
normal secondary sexual characteristics
vas deferent may be absent
what is non-obstructive infertility
low testicular volume
reduced secondary sexual characteristics
vas deferens present
high LH, DSH +/- low testosterone
how do you treat male infertility
treat any specific cause eg. reversal of vasectomy, carbegoline if hyperprolactinaemia
Intracytoplasmic sperm injection
Donor insemination
general advice for male infertility
frequent intercourse - 2-3x per week <4 units of alcohol per day stop smoking BMI<30 Avoid tight fitting underwear and prolonged hot baths/saunas Certain occupations Complementary therapies and non-prescription drugs benefits of antioxidants
when would you use surgical sperm aspiration
azoospermia
sperm aspirated surgically
sperm then injected into oocyte (ICSI)
