Control of pregnancy and birth Flashcards
what does hCG stand for?
Human chorionic Gonadotrophin
what is hCG produced by?
trophoblast
what is the trophoblast?
cells that form the otter layer of a blastocyst (inner cell mass)
what does hCG do?
supports the CL to keep producing oestrogen and progesterone, preventing menstruation
when does hCG production peak?
10 weeks
what happens at the 10 week point to hCG production?
peaks and then the placenta takes over
Where are oestrogen and progesterone produced from during pregnancy?
-1st 3 months from the CL (driven by hCG) and then after from the placenta-linked to foetus
What does oestrogen do during pregnancy?
stimulates uterine growth, prepares the uterus for labour and promotes breast duct development
what controls oestrogen during pregnancy?
placental CRH (corticotropin=ACTH… adrenocorticotrophic hormone)
What does progesterone do during pregnancy?
relaxes the uterus, promotes a cervical plug and stimulates milk gland development in breast
what is progesterone synthesised from and where?
Synthesised in the placenta from cholesterol
4 main things oestrogen does during pregnancy.
-promotes connections (gap junctions) between the myometrial cells
-makes the myometrium more sensitive to ooxytocin
increases prostaglandin production
-promotes mamary duct development
Oestrogen, by making the myometrium more sensitive to oxytocin and promoting gap junction formation in myometrium what does this do?
increases the uterine contractility
what does an increase in prostaglandin production due to oestrogen do?
softens the cervix
why does HPL stand for?
Human placental location (aka human chorionic somatotropin)
what does HPL do?
Anti-insulin action in mother boosts available nutritional substrate…
its a placental derived peptide hormone, supports foetal well being
describe what the uterine is like in each trimester during pregnancy.
1+2 trimester= quiet uterus (progesterone effect)
3 trimester= generally increasing uterine excitability, mild contractions
what is relaxin, what produces it and what does it do?
Hormone produced by the CL and the placenta. Causes the softening of the cervix and pelvis ligaments
what does the increase in uterine contractions cause?
- foetus to press on the cervix
- dilation of cervix
- +ve feedback involving oxytocin
- foetus forced out through birth control
what does oxytocin do?
-promotes uterine contractions in the final stages via positive feedback through various pathways
what is the positive feedback cycle during labour that causes birth eventually
uterine contractions
foetus pushes on cervix
increase in oxytocin from maternal pituitary via nervous reflex… positive feedback causes more uterine contractions..
how do progesterone contraception pills work?
high levels of progesterone cause negative feedback so hypothalamus produces less GnRH and A.pit less FSH and LH … stop ovulation
Wild card… Male puberty… explain.
Hypothalamus produces GnRH, A.pit produces FSH and LH… in testes sertoli cells perform spermatogenesis and leydig cells produce testosterone
