Female Sex Hormones Flashcards
What happens in females in the absence of SRY protein?
Gonadal cortex becomes ovary
What happens to females in the absence of testosterone?
Wolffian duct to degenerate
What happens to females in the absence of anti-Mullerian hormone?
Mullerian duct becomes the fallopian tube, uterus + upper part of the vagina
How long is the cycle?
28 days
What are the 2 phases of the cycle?
Follicular cycle
Luteal cycle
Describe the hormonal control of the early to mid follicular phase
1
Low levels of oestrogen exert negative feedback to GnRH, FSH + LH
Oestrogen promotes more oestrogen secretion by the follicle
AMH prevents more follicles from developing
Describe the hormonal control the late follicular phase + ovulation
2
Rising levels of oestrogen + progesterone
= LH surge
FSH suppressed by inhibin
Describe the hormonal control of early to mid-luteal phase
3
Combined oestrogen + progesterone shut off FSH + LH
Describe the hormonal control of the late luteal phase
4
Oestrogen + progesterone fall when corpus luteum dies
Gonadotropins start follicular development of new cycle
What is high during ovulation?
LH
FSH
Oestrogen
What are the ovarian steroid hormones?
Oestrogens
Progestogens
Androgens
How does oestrogen work?
Mediated by oestrogen receptor
Oestrogen receptor complex binds to specific hormone response element
Activates the transcription of target genes
What is the function of oestrogen?
Development + regulation of female reproductive system + secondary sex characteristics
Maturation of germ cells
Provision of hormonal timing
Development of tissue for implantation
Establishment of milieu
Provision of hormonal influences
Anabolic effects on bone + cartilage
What is fertilisation driven by?
Progesterone
What happens during fertilisation?
Sperm
Fertilisation
Blastocyte attaches itself to uterine wall
Blastocyst is implanted in endometrium
What happens after fertilisation?
Placenta secretes hCG
What does hCG do?
Prevents corpus luteum from developing = progesterone + oestrogen secretion continued
Maintains integrity of uterine wall
How does placental hormones maintain pregnancy?
hCG supports corpus luteum
Corpus luteum + placenta produce progesterone
Oestrogen synthesised by feto-placental function
Placental lactogen provides fuel for the baby
How does placental lactogen work?
Placental growth hormone
Breaks down fats from mother for baby
What secretes milk?
Alveoli cells
They are clustered in lobules
What is E2 for in mammary gland development?
Ductal growth
What is progesterone for in mammary gland development?
Alveolar proliferation
What helps lactation?
Prolactin + oxytocin
What is the production of oxytocin stimulated by?
Oestrogens
Inhibited by progesterone
What is seen in menopause?
Irregular periods
Ovaries fail to respond to FSH
Number of follicles decrease
Increase in FSH + LH to combat low oestrogen
What are the symptoms of menopause?
Hot flushes
Night sweats
Decrease libido
Irregular periods
Mood swings
Vaginal dryness
How does COC work?
Inhibits follicular development + prevents ovulation
How does POP work?
Prevent implantation
Decrease amount + viscosity of mucus
What is the mechanism for oral contraceptives?
Oestrogen + progesterone prevent eges from being released from ovaries
Progesterone causes thinning of endometrium = prevents implantation
Progesterone thickens mucus = prevents sperm reaching egg
What do infertility drugs do?
Stimulate secretion of FSH + LH
= stimulates maturation of follicles, ovulation + development of corpus luteum
What are the labour-related drugs?
Oxytocin
Selective beta adrenergic receptor antagonists
What does oxytocin do?
Labour
Enhances contractile activity
What does selective beta adrenergic receptor antagonists do?
Prevent smooth muscle contractions
When are selective beta adrenergic receptor antagonists used?
Preterm labour if gestation is >20 weeks
