Lecture 1- Introduction to the reproductive system Flashcards
define reproduction
–The action or process of copying something
–The production of offspring by a sexual or asexual process
Two basic modes of repro:
- Asexual
- Sexual reproduction
human repro through
sexual reproduction
- Halving of chromosomes number by meiosis and the restoration via fertilisation
- Two haploid gametes (one male one female)
- Creates genetic diversity
Hormones regulate both male and female reproductive ability
- Puberty
- Menstrual cycle
- Menopause
Hormones are key to regulation of reproductive lifespan
- GnRH
- LH
- FSH
- inhibin
- Follistatin
Gonadotropin-releasing hormone (GnRH)
is the key tropic hormone for regulating gondadotrope cell function and hence reproduction
Luteinising hormone (LH)
gonadotrophic hormone produce and released by cells in the anterior pituitary, crucial in regulating the function of the testes in men and ovaries in women
Follicle stimulating hormones (FSH)
stimulates follicle growth and oestrogen secretion (spermatogenesis in males)
Inhibin and activin
are closely related peptides produced by the ovary, testes, pituitary gland and placenta that influence gonadotrope function
Follistatin
is structurally unrelated to either inhibin or activin. It is a highly glycosylated pituitary peptide that inhibits gonadotrope function but at one-third the potency of inhibin
hypothalamus pituitary gonadal axis
in males FSh
- FSH stimulates Sertoli cells
- Spermatogenesis
- Inhibin released. Negative feedback on anterior pituitary (FSH only) and possibly hypothalamus
in men LH
-
LH stimulates Leydig cells
- Testosterone released.
- Negative feedback on hypothalamus and anterior pituitary
in females FSH
- FSH stimulates granulosa cells
- Follicular development
- Releases inhibin. Specifically inhibits FSH only
- Granulosa cells convert androgens to oestrogen