Male Physiology Flashcards
(26 cards)
Where do the testis develop?
abdominal cavity of the foetus
What causes the testis to drop into the scrotal sac before birth?
androgen dependant
By what age should the testes have decended naturally?
6 months
Why do the testes need to descend?
lower temp outside the body allows spermatogenesis to occur
nervous reflexes cause muscle contractions to lower or raise the testes according to external temperature
What is Cryptorchidism?
failure of the testes to descend by the time the individual reaches adulthood
What are the implications of cryptorchidism?
reduces the sperm count
if it is unilateral they can still be fertile
What is the treatment of cryptorchidism?
orchidplexy by 12 months to reduce infertility risk
should be performed by 12 years to reduce testicular cancer risk (x6)
What is the role of the sertoli cells?
spermatogenesis from the seminiferous tubules
form a blood-testes barrier - protects sperm against antibody attack
secretes androgen binding globulin - binds testosterone so conc stays high
secretes inhibit and activin hormones - regulate FSH secretion and controle spermatogenesis
What is the role of the leydig cells?
produce testosterone
What covers the head of the sperm?
acrosome - contains enzymes for penetrating the ovum
What is contained in the head, midpeice and tail of the sperm?
head - nucleus
midpiece - mitochondria to power the tail
tail - microtubules
What are the characteristics of GnRH?
released every 2-3 hours
starts being released aged 8-12
under negative feedback from testosterone
What is the role of LH?
acts on Leydig cells and regulates testosterone
release stimulated by GnRH
release inhibited by testosterone
What is the role of FSH?
acts on sertoli cells and enhances spermatogenesis
release stimulated by GnRH
release inhibited by testosterone
What are the effects of testosterone on the body before brith?
masculinises the reproductive tract and promotes the descent of the testes
What are the effects of testosterone on the body during puberty?
promotes puberty and male characteristics - growth and maturation of the male reproductive system
What are the effects of testosterone on the bod in adult life?
controls spermatogenesis, secondary sexual characteristics, libido, penile erection and aggressive behaviour
Where is testosterone produced?
leydig cells
What is the role of inhibin?
inhibit FSH
What is the role of activin?
stimulates FSH
After ejaculation, how is spermatoza liquified?
prostate gland
What is the function of the epididymis and vas deferens?
exit route from the testis -> urethra
concentrate and store sperm
site for sperm maturation
What is the function of the seminal vesicles?
produce semen into the ejaculatory duct, supply fructose, secrete prostaglandins (cause contractility), secrete fibrogen (clot precursor)
What is the function of the prostate gland?
produces an alkaline fluid to neutralise the acidic vagina
produces clotting enzymes to clot the semen inside the vagina
