15.2- fetal development and birth Flashcards
fetal development is weeks __
9+
what occurs in the first trimester (months 1-3)
- first 2 months= embryonic period
- 3rd month= placenta developed genitals fully visible, growth
what occurs in the second trimester (months 4-6)
- 4th month= heart beat,
- 5th month=Covered with fine hairs,
- 6th month= translucent, wrinkly, pink skin, increased weight gain
what are the fine hairs called and when do they cover the baby
lanugo (shed before birth)
5th month
what happens in the third trimester
extensive weight gain, rapidvbrain development, digestive and respiratory systems mature
what are teratogens
substances that cause defects during development
examples of teratogens
smoke, alcohol, drugs, excess nutrients, radiation,etc
parturition= ___
labour
during labour what hormone does the placenta release and what does it do
relaxing which loosens ligaments in pevis, relaxing the cervix
during labour ____ decreases therefore ____ are no longer inhibited
progesterone secretion
uterine contractions are no longer inhibited
when is oxytocin released
during labour
where’s oxytocin released from
hypothalamus, but secreted from posterior pituitary
what does oxytocin do
stimulates the uterus to contract and stimulates release of breast milk
prostaglandis=
more contractions
3 stages of birth
1- dilation
2- expulsion
3- placental
what 3 things happen during the dilation stage of birth
- uterine contractions cause cervix to dilate
- amniotic sac ruptures
- stronger, more frequent contractions
what happens during the expulsion stage of birth
contractions push baby through cervix
what is the placental stage of birth
after baby is born the placenta and umbilical cord are released (afterbirth)
lactation=
formation and secretion of breast milk
what 2 hormones are involved in lactation
- prolactin
- oxytocin
during pregnancy prolactin is inhibited by __+__
estrogen and progesterone (decrease after birth so prolactin isn’t inhibted anymore
where is prolactin secreted from
anterior pituitary
oxytocin is released due to (pathway)
suckling- hypothalamus- posterior pituitary- oxytocin
after lobules contract what happens
milk moves towards nipple through ductcs
