Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
33 Cards in this Set
- Front
- Back
|
what layers must a sperm penetrate to successfully fertilize an ovum |
corona radiata (granulosa) zona pellucida |
|
|
how long after fertilization does it take to transport a fertilized ovum to the uterus |
3 to 5 days |
|
|
what cells facilitate implantation |
trophoblast cells secrete proteolytic enzymes to digest, liquefy the endometrial cells |
|
|
what provides early nutrition for the embryo |
decimal cells: which are endometrial cells that have stored extra nutrients in response to progesterone. Placenta begins to provide nutrition around day 16 |
|
|
what is the blood flow pattern of placenta? |
fetal blood flows through 2 umbilical arteries into villi capillaries where they engage in nutrient exchange with maternal villus sinuses. the fetal blood then returns via umbilical veins. The maternal sinuses flow back through uterine veins |
|
|
how does dissolved oxygen pass into fetal blood |
simple diffusion |
|
|
how does fetus obtain sufficient oxygen when blood leaving placenta has a PO2 of ~30mmhg? |
1.fetal hemoglobin carries more oxygen at the lower partial pressures (20-50%) 2. the fetus has more hemoglobin (50%) 3. the bohr effect |
|
|
how does the double-bohr effect work in the fetus? |
hemoglobin carries more O2 at low pCO2.
fetal blood entering placenta has high pCO2 which rapidly diffuses through membrane, causing relative alkalosis of fetal blood, and relative acidosis of maternal blood.
the double is that maternal bhor shift decreases affinity for O2 and fetal bhor shift increases affinity for O2 |
|
|
how does glucose diffuse through placental membrane? |
facilitated diffusion via placental villi |
|
|
what hormone causes persistence of corpus luteum and prevents mensturation? where does it come from? |
HCG
The syncyital trophoblast cells
presence can be detected 8-9 days after ovulation |
|
|
when does HCG peak |
10-12 weeks |
|
|
what is the consequence of removal of the corpus luteum before 7 weeks of pregnancy |
spontaneous abortion |
|
|
what hormones are secreted by the placenta |
estrogens and progesterone |
|
|
what is the source of estrogen precursors |
mothers adrenal glands and fetal adrenal glands in the form of DHEA. This is sent to the placenta and converted by trophoblast to estradiol, estrone, estriol |
|
|
What are the effects of placental progesterone production? |
1. decidual cell development 2. decreased uterine contractility 3. contribution to development of conceptus and developing morula 4. helps prepare mothers breasts for lactation |
|
|
What recently discovered placental hormone is partially responsible for breast development, some growth hormone effects, and altered insulin sensitivity in the mother (which makes more glucose available to the fetus)? |
human chorionic somatomammotrophin |
|
|
what is the effect of pregnancy on the pituitary gland? |
anterior pituitary enlarges up to 50%
PRL, corticotrophin, thyrotropin increase FSH, LH almost completely suppressed |
|
|
what is the effect of pregnancy on corticosteroid production? |
moderate increase in glucocorticoids
twofold increase in aldosterone which can contribute to hypertension |
|
|
what is relaxin? |
secreted by ovaries and placenta to relax ligaments of symphisis pubis prior to birth |
|
|
what is the weight gain in the average pregnant woman |
25-35 lbs mostly occurring during the last 2 trimesters
~8 pounds baby ~4 pounds amnionic fluid ~2 pounds breasts ~3-13 lbs of fat |
|
|
what is the effect of pregnancy on BMR? |
increase by 15% |
|
|
what is the effect of pregnancy on cardiac output, respiration and maternal blood volume |
CO- increases by 30-40%
Respiration- increase in respiratory rate
Blood Volume- Aabout 1-2L of extra blood |
|
|
what is preeclampsia of pregnancy |
increase in arterial blood pressure to hypertensive levels in pregnant women toward the end of pregnancy
possibly caused by reduced blood flow through placenta, may have something to do with increased inflammatory cytokines |
|
|
what is eclampsia |
severe preeclampsia characterized by vascular spasm, kidney problems, liver malfunction, and general toxic response
often fatal without treatment |
|
|
what hormonal factors increase uterine contractility |
increased estrogen to progesterone ratio
increased oxytocin
increased uterine and cervical stretch |
|
|
what is a periodic, weak, slow, rhythmic uterine contraction that occurs throughout pregnancy |
braxton hicks contractions |
|
|
what kind of feedback regulate the birthing process |
positive feedback loops |
|
|
what positive feedback mechanisms are active in labor |
stretch of cervix causes uterus to contract which stretches cervix more
cervical stretching increases oxytocin, which increases uterine contractility, strengthens contractions, stretches cervix more
each positive feedback cycle must be stronger that the one preceding it to prevent retrograde decline |
|
|
what is the most common presentation of the fetus? |
head comes out first (95%) if feet or buttocks come first it is a breech birth |
|
|
what is the first stage of labor, how long does it last? |
progressive cervical dilation 8-24 hours |
|
|
what is the second stage of labor |
rupture of membranes and movement of fetus through the birth canal. can last from 1-30 min or more |
|
|
what becomes of the placenta after birth |
it is shed roughly 30-45 minutes later due to sheering effect. bleeding is limited to ~350ml |
|
|
what causes labor pains |
hypoxia of uterine muscle, cervical stretching, perineal stretching, tearing etc.. conducted through somatic nerves
uterine pain is transferred through visceral pathways |
