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141 Cards in this Set

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  • Back
what three steps of reproduction occur within the female reproductive tract?
internal insemination, internal fertilization and internal gestation
What is the placenta composed of?
chorion (extraembryonic membranes of the fetus) and decidua (endometrial tissue form mom)
what three endocrine systems are interacting during pregnancy?
maternal, fetal and placental
what is the purpose of vaginal tenting?
to draw cervix away from vagina to create a local reservoir for sperm.
what is capacitation? where does it occur?
transient event that must occur before sperm can fertilize the egg. Occurs in oviduct.
where do uncapacitated sperm bind? what is the purpose of this?
bind epithelium of oviduct; it increases the lifespan of the sperm.
what are the 4 ways in which capacitation modifies spermatozoa?
1) alters membrane fluidity by removal of cholesterol from membrane.
2) removes proteins and/or carbs that may block binding sites for egg
3) changes membrane potential that may assist Ca to enter sperm and facilitate acroosmal rxn
4) protein phosphorylation.
What three layers must sperm pass thru?
cumulus, zona pellucida and fusion of sperm and plasma membrane of egg.
what is the cumulus composed of? how does the sperm get thru this?
hyaluronic acid. Sperm has membrane bound hyalurnidase to eat thru that layer.
what is the zona pellucida composed of? what does sperm bind to in this layer? what does that cause?
glycoprotein: ZP1, ZP2, ZP3
sperm binds to ZP3 which triggers an acrosome reaction and enzymes are released that digest the zona pellucida.
why does sperm bind ZP2?
to be held in place while the zona is digested.
T/F
the egg is metabolically active before and after sperm egg fusion.
FALSE

the egg is metabolically quiesent until sperm egg fusion.
how is polyspermy prevented?
the egg is metabolically quiesent until sperm egg fusion, so the same egg cannot be activated by multiple sperm
when is the egg finally haploid?
when the sperm egg fusion occurs because that triggers the completion of meiosis.
what triggers the egg "wakes up" events?
Ca release
what layer hardens preventing polyspermy?
zona pellucida
increased Ca stimulates the recruitment of _______ within the egg that will synthesize _____ needed for early embryonic development.
stored maternal mRNA; proteins
what layer of cells separates and forms the chorionic villi that indigitates with the endometrium? what two hormones are important for this process?
the trophoblasts; prostaglandins and histamine
what does the blastocyst secrete? why?
secretes immunosuppressive agents to avoid rejection by the maternal immune system.
during implantation, what sustains the corpus luteum even though LH is rapidly declining? what does it act as? what does it promote?
human chorionic gonadotropin (hCG). Acts as an immunosuppresive agent. Promotes trophoblast growth and placental development.
during week one, what encapsulates the embryo?
zona pellucida
what is present at day 3 of fertilzation and development?
16 cell morula.
what is formed at days 4-5?
blastocyst cavity.
what are the two cell types of the blastocyst?
eccentric inner cell mass and outer, epithelial-like layer of trophoblasts.
what is the embryonic pole?
trophoblasts cells that are adjacent to inner cell mass.
what are the three stages of implantation?
apposition, adhesion and invasion
what is required before implantation occurs?
hatching- degeneration of the zona pellucida
where does apposition occur? why does it occur there?
at a site where the zona pellucida is ruptred or lysed so it is possible for the cell membranes of the trophoblast to make direct contact with cell membranes of the endometrium.
what is the correct orientation in apposition?
the inner cell mass points towards the endometrium.
on the intracellular site, what do the receptor ligands interact with?
cytoskeletal elements
on the extracellular side, what type of receptors are located? (adhesion)
receptors for matrix proteins (collagen, laminin and fibronectin).
what happens during the invasion phase of implantation?
trophoblasts differentiate into two layers: syncytiotrophoblasts and cytotrophoblast.
what is the syncytiotrophoblast?
the outerlayer of the trophoblast. It is multinucleated without cellular boundaries. It has long protrusions that extend between uterine epithelial cells(decidual lining).
what is eventually penetrated by syncytiotrophoblast?
the basement membrane of uterine epithelial cells.
what happens to the decidual cells in the region of the invading syncytiotrophoblast? what is released?
the decidual cells degenerate; lipids and glycogen are released to provide nutrients to the embryo.
what is the cytotrophoblast layer?
the inner layer of the trophoblast. It initially provides a layer of continuously dividing cells.
what begins secreting hCG at implantation?
syncytiotrophoblasts
when does endocrine function begin?
at implantation
what is the first detectable sign of pregnancy?
plasma level of hCG
at ten weeks, what do the syncytiotrophoblasts start producing? why?
they start making progesterone independent of the corpus luteum because they have become steriodogenic
syncytiotrophoblasts take on the function of what three activities?
gas transfer, facilitated transport, and pinocytosis / transcytosis.
what is decidualization?
enlargment and engorgement of stromal cells as they fill with lipid and glycogen
what is the function of the decidua?
to form an epithelial sheet with adhesive junctions to inhibit migration of implanting embryo.
what does the decidua secrete? what is the function of the secreted substances?
factors that moderate activity of syncytiotrophoblastic-derived hydrolytic enzymes. This regulates invasion of the embryo and placenta so it never reaches the myometrium.
what are the four layers of the chorionic membrane?
syncytiotrophoblasts, cytotrophoblasts, mesenchyme and fetal blood vessels.
where is maternal blood trapped?
in the intervillous space, between th decidua capsularis (mom side) and the villi (fetal).
what types of arteries, in the mature placenta, empty directly into the intervillous space? what drains these arteries?
spiral arteries; maternal veins
what does the original uterine endometrium become?
decidua pareetalis
early nutrition for the placenta is from what? what is early absorption from?
nutrition: trophoblastic digestion
absorption: nutrients form the endometrium
what supplies nutrition for the placental later on in the pregnancy?
diffusion through placental membrane.
near the end of pregnancy, what is the mean PO2 of maternal blood in placental sinus? what is the mean PO2 of fetus after oxygenation?
~50 mmHg; 30 mmHG
T/F
Fetal Hb has higher O2 affinity than adult Hb.
True
what kind of shift is caused by the fetus's demand for O2?
double bohr shift
what are the 5 endocrine functions of the placenta?
1) maintain pregnant state of uterus
2) stimulate lobuloalveolar growth and function of breast
3) adapt maternal metabolism and physiology to support a growing fetus
4) regulate portions of fetal development
5) regulate timing and progression of partuition.
what types of hormones are secreted by syncytial trophoblasts?
gonadotropin like homrones (LH and FSH); hCG and hCS
how many days does it take for hCG to appear in serum?
at most 9 days
What are the two subunits that hCG consists of? what is the difference between the two?
alpha and beta. Alpha is identical for FSH, LH and TSH and the B subunit has only an 80% homology to B subunit of LH
how is hCG secreted in regards to the SCT layer?
The CT layer stimlates the LHRH which then stimulate sthe SCT to secrete hCG via paracrine action.
what is responsible for morning sickness in some people?
rapid rise in hCG
T/F
no hCG enters fetal circulation.
FALSE
a very small amount enters 1%-10%
what does hCG stimulate in male fetuses?
leydig cells to produce the testosterone critical for sexual differentiation.
what is detected at 5 weeks and continues to rise throughout pregnancy in proportion to the weight of the placenta?
human chorionic somatomammotropin.
what is hCS? what does it cause?
a protein hormone with similar functions as prolactin and GH; causes decrease insulin sensitivity and decreased glucose utilization in the mother; directs larger flow of glucose to the fetus. also stimulates the development of mammary glands.
what does relaxin do?
relaxes pubis and helps dilate cervix
what enzyme do SCT cells lack?
17 alpha hydroxylase
what kind of receptors do SCT cells have?
LDL receptors
what is required to maintain q quiescent myometrium and pregnant uterus?
progesterone
T/F
progesterone production by the placenta is completely independent of the fetus and is regulated.
FALSE

it is not regulated
how does progesterone quiet uterine contractions?
by inhibiting prostaglandins
what affect does progesterone have on the mother?
increases capacity of alveolar pouches to hold milk
what role does progesterone play in regards to the respiratory center of the fetus?
stimulates respiratory center to get rid of excess CO2 produced by fetus.
what produces estrogen during pregnancy?
SCT cells
where do androgens come from?
fetal adrenal cortex
T/F
The fetal zone expresses little or no 3B-HSD
true
what is released from the fetal zone of the adrenal gland during gestation?
androgen DHEA-S
what is the production of DHEA in the fetus is dependent on?
release of ACTH from fetal pituitary
what converts DHEA to estriol?
placenta
what can be used to assess fetal well being?
estriol
what affect does estrogen have on placental blood flow, LDL receptors and partuition?
increase placental blood flow, increase LDL receptor in SCT layer and induce factors involved in partuition.
What is estrogen's role in the uterus?
stimulates growth of uterine muscle, softens pelvis along with relaxin and causes enlargement of external genitalia
T/F
estrogen inhibits Progesterone synthesis.
FALSE
augments
what conversion does estrogen stimulate in the placenta?
cortisol to cortisone.
initially where does DHEA come from?
adrenals of the mother
why do prolactin levels in the mother rise?
due to increases in estrogen
why does LH and FSH decrease with the maternal endocrine?
due to negative feedback from high estrogen and progesterone
what happens to the mother's thyroid gland during pregnancy?
increases in size and level of T4 and T3 can double.
what affect does estrogen have on thyroxine binding globulin?
it increases it so it increased hormone binding.
The first trimester changes of thyroid gland are in parallel with what?
changes in hCG
what happens late in pregnancy in regards to cortisol production? why is that important?
there is a serge in cortisol production which is important for the initiation of lactation.
how many days from ovulation is pregnancy? from last menstrual period?
ovulation: 266 days; menstrual: 280 days
how much does cardiac output increase during 1st trimester? when does it increase again?
35-40%; slowly until term
where is the majority of CO distribution targeted?
40% increase in renal flow; 15% in uterine flow.
why is than an increase in CO flow to the skin and breasts?
skin= heat dissipation; breast- mammary glands
what three organs experience no change in flow (cardiac) during pregnancy?
brain, gut or skeleton
How does pregnancy affect MAP? why?
MAP decreases during mid-pregnancy with an increase in 3rd trimester. Due to a decrease in peripheral vascular resistance and the vasodilating effects of progesterone and estrogen
what position gives the highest CO of the mother?
lateral recumbent
what will happen to venous return if the mother is supine?
the fundus of the uterus rests on the inferior vena cava near L5 impeding venous return.
what is the increase in blood volume during pregnancy due to? which trimesters are specifically affected?
due to an increase in plasma volume and erythrocytes; 2nd and 3rd trimester.
what affect does pregnancy have on the diaphragm?
the diaphragm rises ~4 cm due to relaxing effects of P
T/F
Pregnancy alters the Mother's vital capacity.
FALSE

there is a net decrease in residual volume with no appreciable change in vital capacity.
what affect does pregnancy have on alveolar ventilation? what does this create for the mother?
pulmonary resistance falls facilitating airflow. a decrease in maternal PCO2 (from 40-32)
why is additional protein necessary during pregnancy? how much is necessary?
protein is for the fetus, placenta, uterus, breasts and BV. need an additional 30 grams.
why do you need an additional amount of iron during pregnancy? how much? how much do you need to absorb per day?
to support maternal Hb mass, the placenta and the fetus. Need a net gain of ~800 mg. per day: 7.0 mg/day
why is folate necessary during pregnancy?
required to make additional RBC; lowered plasma folate can cause neural tube defects in fetus.
in regards to maternal weight gain, how much can be attributed to intra-uterine things such as the fetus, placenta and amniotic fluid? what is the rest due to?
5 kg; maternal gain such as the uterus, blood, breast and adipose/interstitial fluid.
what is partuition?
process of uterine contraction leading to childbirth
what are the 3 stages of labor?
1)Dilation and thinning of cervix due to uterine contractions forcing fetus against cervix (several hours)
2)Delivery of fetus (~ 1 hour)
3)Delivery of placenta (> 10 min)
which stage of labor is the fastest?
delivery of the placenta
what three things does increased cortisol from the fetus lead to?
1) maturation of lungs
2) increase in liver glycogen stores
3) increase in intestinal transport and digestion
what stimulates the contraction of uterine smooth muscle cells?
prostaglandin from uterus, placenta and fetal membranes.
what potentiates contractions induced by oxytocin? how?
PG by forming gap jxns between smooth muscle cells.
what affect does PG have on the cervix?
softening, dilation and thinning of the cervix
what stimulates PG production? how?
oxytocin by binding to the receptor on decidual cells
T/F
Maternal oxy is thought to initiate labor but maintains labor
False
Maternal oxy is NOT thought to initiate labor but maintains labor
when does fetal oxytocin rise? what is it involved in?
at the beginning of labor. Involved in initiation of parturition.
what hormone is relaxin related to? what produces it?
insulin; corpus luteum, placenta and decidua.
what is the job of relaxin? when does production increase?
keeps uterus quiet during pregnancy, relaxes pelvic area prior to labor. Production increases during labor to help dilate cervix.
what affect does estrogen have on the oxytocin receptors? where?
increases the number of oxytocin receptors in myometrium and decidual layers.
by how much does the receptor number rise during early labor?
200 fold
what are the four steps involved with the theory for the onset of strong contractions during labor?
1) baby's head stretches cervix
2) cervical stretch excites fundic contraction
3) fundic contraction pushes baby down and stretches cervix some more
4) cycle repeats over and over again
what is mammogenesis?
proliferation of alveolar and duct cells
what is lactogenesis?
milk production by alveolar cells
what is galactorrhea?
excessive or continued secretion of milk even after suckling has stopped
what is lactation?
lactogenesis and milk let down
what does lactogenesis rely on?
prolactin
what allows the milk to let down?
oxytocin
what is the mammary gland made up of?
supporting tissue and glandular tissue
what does glandular tissue consists of?
the alveoli and ducts
where does the lactiferous duct carry secretions during lactation?
outside
during prenatal development of mammary glands, what are the mammaries sensitive to?
estrogen
what is present, in regards to mammary glands, at birth?
rudimentary duct system
what is present or developing, in regards to mammary glands, from birth until puberty?
some growth of secretory tissue and development of supporting adipose tissue
what happens to the mammary glands during puberty? why?
sudden growth due to an increase in estrogen. The ducts grow, lobules and epithelial buds form at ductus terminus and there is an increase in CT and adipose tissue.
what happens to the mammary glands during the menstrual cycle (folliculuar and luteal)?
follicular: duct maintenance
luteal: lobular/alveolar maintenance
during pregnancy, what is high? what does that cause?
high estrogen, progesterone and hCS which causes max growth of lobular/alveolar and duct system
what is prolactin essential for?
P and E to have mammotropic effects
what does Prolactin stimulate? what prevents it?
lactogenic apparatus; prevented by excess P and E
why is milk synthesis initiated after parturition?
due to decreased P and E
what maintains high levels of prolactin after birth?
sucking
what can prevent subsequent ovulations (and therefor pregnancies) while lactating?
high prolacting which can inhibit GnRH keeping LH low.
what is milk?
milk is an emulsification of fats in an aqueous solution containing sugar, proteins and inos