Pregnancy and parturition Flashcards
what is the purpose of the menstrual cycle?
promote growth of the lining of the womb so the lining of the womb proliferates and becomes receptive at the right time of ovulation, release of the egg to accept the egg whether or not it’s worth accepting or rejecting
what is the menstrual cycle ?
feedback system between hormone released from brain and lining of the womb so there is appropriate release of the egg. Through gonadotrophin luteinizing hormone-follicle stimulating hormone and surge in oestrogen-drives proliferation of lining for the womb.
once the egg is released what does the ovary become
corpus luteum
what hormone does the corpus luteum produce
progesterone
what happens after ovary becomes corpus luteum?
egg is released and fertilised over next few days it forms into a blastocyst-arrive in time for implantation so lining of the womb is prepared
After the blastocyst is formed where does it implant?
side of uterus and outer cell layer called syncytiotrophoblasts
what are syncytiotrophoblasts?
specialised layer of epithelial cells
function of syncytiotrophoblasts
This produces hormone called human chorionic gonadotrophin-copy of follicle stimulating hormone and luteinising hormone -tells ovary to keep producing progesterone and oestrogen for first 12 weeks
how can the womb collapse?
signal does not arrive -corpus luteum will cease, progesterone falls
what does progesterone do?
suppress mitral contractions through pregnancy
2 functions of progesterone
-essential for maintenance of pregnancy in all mammals.
-promotes formation of mucus plug in cervical canal-block the lower chamber ensuring it stays insulated from infection
what does oestrogen do?
responsible for growth of uterus, proliferation of uterine cells and increase in size and increase size of breasts
2 functions of oestrogen
making ductal structures-releasing milks once babies born
-preparing uterus, and cervix for labour by induction of pro-labour genes.
what hormone does the placenta directly make?
progesterone can be made directly in here by taking cholesterol and manufacture progesterone
how does the placenta make oestrogen?
for oestrogen it needs to take a substance which is coming from foetal adrenal cortex -produces precursor called dehydrated epi androstenedione sulphate(DHEA). It is then converted across placenta into maternal liver where it is de sulphated into DHEA which the placenta uses to make estrogen
foetal hypothalamic pituitary adrenal axis
brain is growing, adrenal is growing
what hormone does the foetal hypothalamic pituitary adrenal axis produce? (happens in feedback loop)
produce stress hormone-cortisol and drives change in body and gives important feedback and growth of baby.
stimulation of foetal pituitary releases what?
corticotrophin-which feeds back to adrenal to produce more cortisol- this is the feedback loop.
what are the 3 differences between maternal circulation and foetal circulation lead to ?
ability to exchange gases
-ability to exchange nutrients
-ability to enter into an endocrine dialogue between mother and baby- 2 organisms are connected.
what is the function of umbilical cord?
baby gets oxygen and all of its nutrients.
when would there not be gas exchange leading the baby to not breathe?
lungs when in amniotic fluid -when filled with fluid there is no gas exchange
Amniotic sac
important for creating a sterile environment
Onset of labour
is water breaking -the rupture of amniotic sac
what can cause pre term births
if amniotic sac breaks to soon
Corian
a membrane that surrounds a developing fetus in conjunction with the amnion