ppwt 7 conception and pregnancy part 2 Flashcards
what is the beginning of the pregnancy
implantation
where does the fertilization of the ovum occurs
in the ovuduct
what moves the zygote along the oviduct of the uterus
the ciliated cells
true or false
the attachment of the conceptus (embryo) is an evolutionary step
true
until 8 cell stage, cells are…
totipotent
at 16 cell stage, cells differentiate into
inner cell mass and trophectoderm (blastocyst)
blastocyst will enter in the uterus …. days after fertilization
7-8 days
what is implantation
embryo attaches to the endometrium
what implantation involves
involve apposition of the microvilli present on the trophectoderm (blastocyst) with pinocytes (fused microvilli) on the endometrial cells
what hormone is present during implantation
progesterone
changes in the uterine endometrium during the menstrual cycle
days 1-3: menstruation
day 3-14 : estrogen regulate proliferative phase
day 14-28: progesterone regulate secretory phase
- day 14 is ovulation
the placenta consists of what
consist of a round patch of chorionic tissue that forms the fetal-maternal interface. Vessels from the exchange zone merge to form the umbilical vessels that supply the fetus with blood
what is exchanged in the placenta of primates
glucose amino acids, no proteins (fetus synthesizes proteins), no lipid (placenta synthesizes ipids)
true or false
peptide hormones do not cross, but lipid soluble hormones do
true
which toxins and substances can cross the placenta
alcohol, lead, mercury, antibiotic
which pathogens can cross
HIV, herpes and syphilis
which hormone is detected by the pregnancy testes
hCG - human chorionic ghonadotropin
why hCG is important in the beginning of the pregnancy
hCG stimulates the corpus luteum that will assume primary responsibility for progesterone secretion
after 2.5-3 months what assumes the progesterone responsability
the placenta
what is the fetalplacental endocrine unit
cholesterol will make pregnenolone that will enter the placenta and make progesterone and progesterone which is important in the maintenance of pregnancy and then progesterone go back to the maternal compartment to make DHEA that will enter the placenta and be converted into various types of estrogens.
DHEA can also go to the liver for the final metabolism and excretion
what is the maternal adaptation to pregnancy
- cardiovascular (heart rate increases)
- pulmonary (tidal volume increases)
- gastrointestinal (increased gastric emptying time)
- renal (flow increase 25-50%)
- weight
what hormone stimulates duct formation and accumulation of fat in the breast
estrogen
what are the enzymes that induce enzymes that are necessary for milk production
glucocorticoids, prolactin and placental lactogen
why a pregnant women do not produce milk
becuse the concentrations of estrogens and progesterone prevent milk production
what happens with the hormones after the baby is born
estrogen and progesterone decreases but prolactin stays high which make milk production
why when a mother is lactating the child she cannot get pregnant
because high prolactin levels inhibit normal cycling of GnRH and thus prevent ovulation
what happens during parturition
- Fetal stress - increases fetal ACTH - which makes fetal cortisol
- fetal cortisol will make enzyme that converts progesterone in estrogen
- estrogen will increase secretion by the genital tract which will make more lubrification
- estrogen will increase myometrical contraction - increase pressure - increase cervical stimulation - increase oxytocin and so there will be a maximum pressure
- fetal cortisol will make prostaglandin F2 alpha that will make luteolysis (cessation of progesterone contraction)
- prostaglandin will also make relaxin that will make pelvic ligament stretching
what are the main hormones during parturition
- fetal corisol that increases
- progesterone that decreases
- estrogen will induce labor by making lubrification + pressure/contraction that is also the cause of the decrease of progesterone
- prostaglandin that induce labor by decreasing progesterone and made relaxin
after the baby is born how many days the steroids return to normal level
1-3 days
what happens to the pituitary size during pregancy
it increases by 1/3 of the size and does not decrease until lactation ends
what are the function of hormones FSH/LH
ovulation
prolactin do what to FSH/LH
decrease concentration and so prevents ovulation
what is the neurohormonal control of milk ejection
- sucling will stimulate neuronal signals
- it will reach hypothalamus that will synthesize oxytocin that will be secreted by the posterior pituitary
- it will go to mammals glands the alveolar cells have oxytocin receptor and it will make milk ejection
- at the same time prolactin is produced by the anterior pituitary gland that will make milk prodution
