Lecture 25 -- review questions Flashcards
during the first weeks of pregnancy, what organ is the primary source of pregnancy-related hormones?
and after that few weeks, what organ takes control of the hormone production?
corpus luteum –> first weeks
placenta –> later weeks
what does hCG stand for?
human chorionic gonadotropin
what is the function of the human chorionic gonadotropin?
prevents involution of corpus luteum
stimulates its growth and secretory activity
when do hCG levels peak: early, mid, or in late (~week 40) pregnancy?
early (~week 10)
what is one of the functions of the placental lactogen?
makes glucose more available to the fetus
fatty acids more available to the mom
when do placental lactogen levels peak: early, mid, or in late (~week 40) pregnancy?
around late pregnancy
~week 30
right before birth
what are the 3 functions of progesterone in pregnancy?
1) inhibit premature uterine contractions and menstruation
2) stimulate endometrial stromal cell differentiation into decidual cells that control embryo implantation
3) stimulate mammary alveoli development
what hormone prevents premature uterine contractions and menstruation (=destruction of the functional layer of the endometrium) during pregnancy?
progesterone
what does progesterone do to the endometrium?
stimulate endometrial stromal cells to differentiate into decidual cells –> control embryo implantation
when do progesterone levels peak: early, mid, or in late (~week 40) pregnancy?
late pregnancy
around birth
when do estradiol (estrogen) levels peak: early, mid, or in late (~week 40) pregnancy?
late pregnancy
around birth
when do cortisol levels peak: early, mid, or in late (~week 40) pregnancy?
late pregnancy
around birth
what is one of the functions of cortisol in pregnancy?
to mobilize amino acids for fetal protein synthesis
are progesterone and estradiol being synthesized during the first weeks of pregnancy or only at the end?
during first weeks and at the end
start –> synthesized by corpus luteum
end –> synthesized by placenta
what does relaxin do?
(from ovaries and placenta)
relaxes the pelvis and widens the cervix
what organs synthesize relaxin?
ovaries and placenta
during pregnancy, what happens to the tidal volume? why? (tip: 2 reasons)
increase:
1) greater need for oxygen
2) progesterone increases the sensitivity of the medullary respiratory center to CO2
what results from the influence of progesterone on the maternal respiratory system?
increases the sensitivity of the medullary respiratory center to CO2
what does dyspnea mean?
(difficult breathing)
why is dyspnea typical of the 3rd trimester of pregnancy?
diaphragm is pushed superiorly by the increasing size of the uterus
why do pregnant women suffer from heartburn?
and hemorrhoids, varicose veins, or edema?
enlarging uterus presses upward on stomach –> causes gastric reflux
uterus puts pressure on the large pelvic blood vessels –> interferes w/ venous return from the legs and pelvic regions
what are varicose veins?
twisted, enlarged, damaged veins
blood doesn’t flow well back to the heart
what happens with the total body water of the pregnant: increase or decrease?
how about blood volume and cardiac output?
and urine volume?
total body water –> increase
blood volume –> increase
cardiac output –> increase
urine volume –> increase
why are frequent urination and urgency common in pregnancy?
kidneys produce more urine
enlarged uterus puts pressure on bladder
what causes constipation in pregnancy?
decreased intestinal mobility
more nutrients absorbed
what are 2 typical changes that happen in the skin during pregnancy?
changes in pigmentation:
- more melanocyte activity –> darker skin in some areas
stretch marks
what is the linea nigra? which cells are implicated in the emergence of the linea nigra?
linea nigra == dark line from umbilical to pubic region –> line on belly
increased melanocyte activity
what is labor?
a series of continuous, progressive contractions of the uterus
–> help the cervix to dilate and to thin
–> allow the fetus to move thru the birth canal
what is parturition?
process of giving birth
what are Braxton Hicks contractions?
“false labor”
weak, irregular contractions
what hormone is responsible for Braxton Hicks contractions?
estrogens from placenta
at the end of pregnancy, estrogen levels are pretty high
what is one of the effects of these high estrogen levels in the uterus? (tip: increase the receptors for one hormone, which one? why to increase those receptors?)
increases oxytocin receptors on uterus
–> oxytocin stimulates the uterus to contract
what stimulus for secretion of oxytocin by the pituitary gland of the pregnant mother just before labor?
cervical stretching –> fetus’s head pushes against the cervix
is oxytocin only produced by the mom?
no; both from fetus and mother’s posterior pituitary gland
what is the role of oxytocin during labor? (tip: 2 things)
stimulate uterus to contract
stimulate placenta to release prostaglandins (which stimulate more vigorous contractions)
what is the role of prostaglandins during labor?
stimulates more vigorous uterus contractions
causes positive feedback loop –> more prostaglandins == oxytocin is released == more prostaglandins released
what 2 factors are responsible for the “true” labor contractions? (tip: one is a hormone, and the other an eocisanoid derived from arachidonic acid)
oxytocin
- stimulates uterus to contract
- stimulates placenta to release prostaglandins
prostaglandins
- stimulates more vigorous contractions of uterus
- positive feedback loop to release more oxytocin == more prostaglandins
what is the positive feedback loop of uterine contraction?
cervical stretching
== more oxytocin secretion
== stimulates uterus to contract
== releases prostaglandins
== stimulates uterus to vigorously contract
== stimulates more oxytocin secretion (== more contractions == more prostaglandins == more vigorous uterine contractions)
what are the 3 stages of labor?
1) dilation stage
2) expulsion stage
3) placental stage
what happens in each stage of labor?
1) dilation stage
- cervix opens (dilates) and becomes thinner (effaces)
- from onset of true labor contractions until cervix is fully dilated
2) expulsion stage
- full cervical dilation until birth of infant
3) placental stage
- placenta and other fetal membranes are expelled by uterine contractions
can the cervix dilate up to 10 cm?
yes, when fully dilated
10 cm is diameter of baby’s head
what is the “breaking of the waters”?
fetal membranes rupture and the amniotic fluid is discharged
what is crowning?
when the top of baby’s head is visible at the vaginal opening
how are the placental and other fetal membranes expulsed from the mom after delivery?
uterine contractions
what is the stage of puerperium?
6 weeks after childbirth –> mother’s reproductive organs return to their original non pregnant condition
what is lochia?
vaginal discharge that comes from shrinkage of uterus (involution) and self-digestion (autolysis) of uterine cells by their own lysosomal enzymes
how does the uterus shrink during the following weeks after labor?
self-digestion (autolysis) of uterine cells by their own lysosomal enzymes –> produces lochia (vaginal discharge)
what is the name of the muscle located under the breast?
pectoralis major muscle
is breast size determined by the amount of adipose tissue or the number of mammary glands each breast contains?
amount of adipose tissue
what is the function of the suspensory ligaments?
attach breast to the dermis and to the fascia of pectoralis major
what is the function of the lactiferous ducts?
drain each lobe, dilates to form a lactiferous sinus opening onto the nipple
where are the lactiferous sinuses located?
opening into the nipple
what is the difference b/n a lobule and a lobe in the mammary gland?
lobule == group of alveoli clusters
lobe == group of lobules
what do lobules contain?
clusters of alveoli
what are alveoli (regarding the mammary gland?) and an alveolus?
alveoli == hollow cavities lined with milk-secreting cuboidal cells (lactocytes) and surrounded by myoepithelial cells
alveolus = single alveoli
what cells are in the alveoli of the mammary gland? (tip: 2)
lactocytes == milk-secreting cuboidal cells
myoepithelial cells == surround the lactocytes in the alveoli
what cells found in the mammary gland’s alveoli are responsible for milk production and secretion?
lactocytes == milk-secreting cuboidal cells that line the alveoli
where do the alveoli drain the milk: directly into the lactiferous duct or the lactiferous sinuses?
lactiferous duct, then into lactiferous sinuses
concerning mammary gland development, at which stage of life do terminal end buds form?
and the alveolar buds?
and the alveoli?
terminal end buds –> puberty
alveolar buds –> pregnancy
alveoli –> formed during pregnancy but fully matured during lactation
what is the hormone that promotes the creation of TEB at puberty?
estrogens
where are TEB located?
ends of lactiferous ducts
what do terminal end buds do?
highly proliferative structures that are responsible for development of almost the entire ductal system
what happens to the lactiferous duct after puberty under the influence of estrogens and progesterone?
elongates and branches
which hormones stimulate the formation of the alveolar buds at the end of the lactiferous ducts?
1) prolactin
2) progesterone
3) placental lactogens
what is alveologenesis?
formation of alveolar buds
what is lactogenic differentiation?
growth and differentiation of alveolar buds into alveoli at the end of pregnancy
can a non-pregnant woman produce breast milk? (tip: does she contain alvoeli?)
no –> she does not contain alveoli
she must become pregnant to form alveolar buds –> fully matured, milk-producing alveoli
can a pregnant woman produce breast milk during the first trimester of pregnancy?
no;
alveolar buds don’t fully mature into milk-producing alveoli until end of pregnancy
what does ductal elongation mean?
lactiferous ducts lengthen and side branch
what is lactation?
infant suckle –> hormones –> mammary glands produce milk
what stimulates prolactin and oxytocin secretion during the lactation period?
baby suckling –> stimulates neural receptors in the nipple
what gland secretes prolactin and oxytocin?
AP PO
anterior == prolactin
posterior == oxytocin
prolactin –> anterior pituitary gland
oxytocin –> posterior pituitary gland
how do oxytocin and prolactin work together during lactation?
prolactin –> milk synthesis by mammary alveolar cells
oxytocin –> contraction of the myoepithelial cells produces milk ejection
if a more neither feeds the baby with breast milk for several weeks nor extracts breast milk with a breast pump, would she be able to produce milk again?
no –> continued breast-feeding is required for continued milk production
what is colostrum?
pre-milk fluid
a fat-poor fluid that contains more protein, vitamin A, and minerals than does true milk
colostrum vs. milk – what’s the difference in composition?
colostrum
- fat-poor
- more protein
- more vitamin A
- more minerals
considering this graph, why do prolactin and oxytocin levels increase and decrease (= are unstable) during lactation (last part of the graph)?
(tip: check what is the stimulus for their release from the pituitary gland)
stimulus for their release is dependent on suckling of baby
suckle == prolactin and oxytocin levels increase
no suckle == prolactin and oxytocin levels decrease
