pregnancy and menstrual cycle Flashcards
what maternal adaptations take place during pregnancy?
CVS
-increase CO, BP, uterine blood flow, RBC and plasma mass
Resp
-increase alveolar ventilation
GI
-Acid reflux and delayed emptying
Skin
- linea nigra - dark central line on abdomen
- stretch marks
- darkened areolar
biochemical
- increased lipid and protein production
- weight gain
- insulin resistance
what are the phases of menstruation?
follicular, ovulation and luteal phase
what happens during the follicular phase of menstruation?
- FSH stimulates the maturation of primary to secondary follilcles and causes them to produce low levels of oestrogen (LH stimulates theca cells to produce precusors needed for oestrogen to be made)
- Low levels of oestrogen causes negative feedback on the hypothalamus and APG causing lowered levels of FSH and LH
- as granular cells carry on making oestrogen and levels increase it has a positive feedback affect on the APG and hypothalamus
- this causes a surge in LH
what causing ovulation? what is released? from where?
LH surge
secondary oocyte
secondary follicle
What happens during the luteal phase of menstruation?
- after ovulation the secondary follicle turns into a corpus luteum and begins to secrete progesterone, oestrogen and inhibin
- progesterone inhibits GnRH release and maintains the endometrium
- inhibin inhibits FSH. preventing the maturation of anymore follicles or LH surges.
- during the luteal phase LH levels drop too low to maintain the corpus luteum if pregnancy doesn’t occurs the corpusluteum degenerates in 2 weeks
- degeneration of the corpus luteum causes the endometrium to slough and increases blood levels of LH and FSH so the cycle can start again
describe the changing levels of the hormones involved in the first half of menstruation?
- initial increase in FSH and LH
- Increase in oestrogen which causes the decrease of FSH and LH
- as oestrogen continues to increase it causes +ve feedback on LH on FSH causing a surge
describe the changing levels of the hormones involved in the second half of menstruation?
- an increase in inhibin and progesterone is seen in the first 7 days
- followed by a decline in inhibin, progesterone and oestrogen
- slow increases of FSH, LH and GnRH is seen in the last 7 days
what are the hormones involved in pregnancy?
- Human chorionic hormone
- oestrogen
- progesterone
- prolactin
- Relaxin
- oxytocin
- Prostaglandins
What is the purpose of Human chorionic hormone in pregnancy? where is it produced?
produced by cytothrophoblasts and synctiotrophoblasts
- supports corpus luteum until placenta is established
- interacts with endometrial receptors
- stimulates oestrogen production
what is the purpose of oestrogen during pregnancy? where is it produced?
produced by the ovaries throughout pregnancy
- regulates the levels of progesterone
- prepares uterus for baby
- prepares breasts for lactation
what is the purpose progesterone during pregnancy? where is it produced?
produced by the corpus luteum at first and then the placenta once established
- prevents uterine contractions
- builds up the uterine lining to prevent miscarriage
what is the purpose of prolactin during pregnancy? where is it produced?
produced by the APG when levels of oestrogen and progesterone are low at the end of pregnancy
- production of milk in the breast tissue
- prevention of ovulation (poor and unreliable)
what is the purpose of relaxin during pregnancy? where is it produced?
produced by the ovaries and placenta. the levels are high during early pregnancy
- limits uterine activity
- softens the cervix and causes cervical ripening in preparation for child birth
what is the purpose of oxytocin in pregnancy? where is it produced?
produced by the PPG
- induces uterine contractions
- promotes reproductive maternal behavior
what is the purpose of prostaglandins in pregnancy? where are they produced?
produced by uterine tissues
-initiation of labour
