ppwt 7 conception and pregnancy part 2

Question 1

what is the beginning of the pregnancy

Answer 1

implantation

Question 2

where does the fertilization of the ovum occurs

Answer 2

in the ovuduct

Question 3

what moves the zygote along the oviduct of the uterus

Answer 3

the ciliated cells

Question 4

true or false
the attachment of the conceptus (embryo) is an evolutionary step

Answer 4

true

Question 5

until 8 cell stage, cells are…

Answer 5

totipotent

Question 6

at 16 cell stage, cells differentiate into

Answer 6

inner cell mass and trophectoderm (blastocyst)

Question 7

blastocyst will enter in the uterus …. days after fertilization

Answer 7

7-8 days

Question 8

what is implantation

Answer 8

embryo attaches to the endometrium

Question 9

what implantation involves

Answer 9

involve apposition of the microvilli present on the trophectoderm (blastocyst) with pinocytes (fused microvilli) on the endometrial cells

Question 10

what hormone is present during implantation

Answer 10

progesterone

Question 11

changes in the uterine endometrium during the menstrual cycle

Answer 11

days 1-3: menstruation
day 3-14 : estrogen regulate proliferative phase
day 14-28: progesterone regulate secretory phase
- day 14 is ovulation

Question 12

the placenta consists of what

Answer 12

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

Question 13

what is exchanged in the placenta of primates

Answer 13

glucose amino acids, no proteins (fetus synthesizes proteins), no lipid (placenta synthesizes ipids)

Question 14

true or false
peptide hormones do not cross, but lipid soluble hormones do

Answer 14

true

Question 15

which toxins and substances can cross the placenta

Answer 15

alcohol, lead, mercury, antibiotic

Question 16

which pathogens can cross

Answer 16

HIV, herpes and syphilis

Question 17

which hormone is detected by the pregnancy testes

Answer 17

hCG - human chorionic ghonadotropin

Question 18

why hCG is important in the beginning of the pregnancy

Answer 18

hCG stimulates the corpus luteum that will assume primary responsibility for progesterone secretion

Question 19

after 2.5-3 months what assumes the progesterone responsability

Answer 19

the placenta

Question 20

what is the fetalplacental endocrine unit

Answer 20

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

Question 21

what is the maternal adaptation to pregnancy

Answer 21

• cardiovascular (heart rate increases)
• pulmonary (tidal volume increases)
• gastrointestinal (increased gastric emptying time)
• renal (flow increase 25-50%)
• weight

Question 22

what hormone stimulates duct formation and accumulation of fat in the breast

Answer 22

estrogen

Question 23

what are the enzymes that induce enzymes that are necessary for milk production

Answer 23

glucocorticoids, prolactin and placental lactogen

Question 24

why a pregnant women do not produce milk

Answer 24

becuse the concentrations of estrogens and progesterone prevent milk production

Question 25

what happens with the hormones after the baby is born

Answer 25

estrogen and progesterone decreases but prolactin stays high which make milk production

Question 26

why when a mother is lactating the child she cannot get pregnant

Answer 26

because high prolactin levels inhibit normal cycling of GnRH and thus prevent ovulation

Question 27

what happens during parturition

Answer 27

1. Fetal stress - increases fetal ACTH - which makes fetal cortisol
2. fetal cortisol will make enzyme that converts progesterone in estrogen
3. estrogen will increase secretion by the genital tract which will make more lubrification
4. estrogen will increase myometrical contraction - increase pressure - increase cervical stimulation - increase oxytocin and so there will be a maximum pressure
5. fetal cortisol will make prostaglandin F2 alpha that will make luteolysis (cessation of progesterone contraction)
6. prostaglandin will also make relaxin that will make pelvic ligament stretching

Question 28

what are the main hormones during parturition

Answer 28

1. fetal corisol that increases
2. progesterone that decreases
3. estrogen will induce labor by making lubrification + pressure/contraction that is also the cause of the decrease of progesterone
4. prostaglandin that induce labor by decreasing progesterone and made relaxin

Question 29

after the baby is born how many days the steroids return to normal level

Answer 29

1-3 days

Question 30

what happens to the pituitary size during pregancy

Answer 30

it increases by 1/3 of the size and does not decrease until lactation ends

Question 31

what are the function of hormones FSH/LH

Answer 31

ovulation

Question 32

prolactin do what to FSH/LH

Answer 32

decrease concentration and so prevents ovulation

Question 33

what is the neurohormonal control of milk ejection

Answer 33

1. sucling will stimulate neuronal signals
2. it will reach hypothalamus that will synthesize oxytocin that will be secreted by the posterior pituitary
3. it will go to mammals glands the alveolar cells have oxytocin receptor and it will make milk ejection
4. at the same time prolactin is produced by the anterior pituitary gland that will make milk prodution