KA.2.2 Hormonal Control of reproduction Flashcards
What is a hormone
chemcical produced at one site and has an effect on another site
What is the site of hormone production
Endocrine glands and are secreted directly into bloodstream
What triggers the onset of puberty
hypothalamus secretes a releaser hormone whose target is pituitary gland
What happens the pituitary gland is stimulated
releases FSH, ISCH or LH these hormones trigger sperm & testosterone production and menstrual cycle
What does FSH do for men
arrives in bloodstream at testes and promotes sperm production in seminiferous tubules
What does ICSH do for men
arrives in bloodstream at testes and stimulates interstitial cells to produce testosterone
What can testosterone for sperm
Stimulates sperm production in seminiferous tubules , activates prostate gland and seminal vesicles
What is Negative feedback control
concentration of testosterone builds up in bloodstream, reaches level where inhibits secretion of FSH and ICSH, leads to decrease in testosterone, which then triggers the whole production again`
How long does menstrual cycle last
28 days
what is the first stage on menstrual cycle
Follicular phase (1st half)
What is the second stage on menstrual cycle
Luteal Phase (2nd half)
What does FSH do for women
Stimulates development and maturation of each follicle,
Stimulates production of oestrogen by follicle in follicular phase
what does LH do for women
Trigger ovulation
Brings development of corpus luteum from follicle
Stimulates corpus luteum to secrete progesterone
What happens when ovary wall secretes oestrogen
Stimulates proliferation (cell division) of endometrium preparing for implantation
Alters cervical mucus becomes thin and watery making it more penetrable by sperm
Peak levels pf oestrogen stimulates surge in secretion of LH triggering ovulation
In Luteal phase corpus luteum secretes progesterone, what does progesterone do
Promotes further development and vascularisation of endometrium into spongy layer rich in blood vessels, preparing for implantation
Inhibits secretion of FSH and LH
What happens when concentration of oestrogen builds up in Follicular phase
Stimulates proliferation and repair of endometrium
Triggers production of LH and FSH (day 14)
what happens when LH is released in follicular phase
causes ovulation causing follicle to rupture and release ovum may result in fertilisation
What happens when high levels of oestrogen and progesterone during Luteal phase
triggers an inhibitory effect on pituitary gland, so concentrations of FSH and LH drop, causing no new follicles develop
what happens when fertilisation occurs
Embryo secretes hormone called Human Chorionic Gonadotrophin which has same effect as LH
What does HCG do when fertilisation occurs
Maintains Corpus Luteum so it doesn’t degenerate and continues to secrete progesterone preventing menstruation
What happens after 6 weeks of pregnancy
placenta takes the job of corpus luteum by secreting progesterone
How are pregnancy tests based off
the presence of HCG in urine
What happens when fertilisation does not happen
Lack of LH leads to degeneration of corpus luteum, rapid drop of progesterone and oestrogen
what to endometrium by day 28 of no fertilisation
ovarian hormones are at such a low levels that endometrium can no longer be maintained leads to menstruation
what is menstruation
loss of inner layer of endometrium accompanied by small volume of blood
