chapter 24 Flashcards
gestation
38 week period of development (40 if counting from mother’s last menstrual period)
zygote
single cell resulting from union of mother/father cells
morula
cluster of identical cells from zygote
occurs in uterine tube generally
blastocyst
partially hollowed structure formed from morula before reaching uterus
group of cells within (inner cell mass) becomes embryo while the rest (trophoblasts) differentiate into tissue to support developing fetus
embryo vs fetus
embryo: growing offspring from conception to 3 months
fetus: growing offspring from 3 months to birth
decidua
maternal portion of the placenta
well-vascularized internal portion of endometrium
chorion
embryonic potion of placenta
forms chorionic villi
what are chorionic villi
projections that break down endometrial tissue creating venous sinuses with maternal blood
can be taken for genetic testing
how many arteries/veins are contained within the umbilical cord?
2 arteries and 1 vein
(arteries house LOW O2 blood and vein houses HIGH O2 blood)
ductus venosus
allows blood coming in from umbilical vein to bypass liver
foramen ovale
allows for high O2 blood to shunt from right atrium to left atrium (bypassing lungs)
ductus arteriosus
allows for high O2 blood to shunt from pulmonary artery to aorta (bypassing lungs)
what portions of the umbilical structures persist after birth?
proximal portions of umbilical arteries persist as arteries to urinary bladder
what is human chorionic gonadotropin?
hormone secreted by blastocyst after implantation
acts like LH stimulating growth and activity of corpus luteum (meaning high amounts of progesterone and estrogen for about 11-12 weeks)
when are miscarriages most likely?
when corpus luteum degenerates and it’s actions are taken over by the placenta
what does progesterone do during pregnancy?
- promotes endometrial secretions which nourishes embryo
- maintains endometrium
- decreases uterine muscle’s ability to contract
- prepares breasts for milk excretion
what does estrogen do during pregnancy?
promotes enlargement of uterus and breasts
what are the 3 hormones produced by the placenta?
placental growth hormone
human chorionic somatomammotropin
relaxin
what does relaxin do?
hormone that softens cervix and relaxes sacral joints/pubic symphysis to prepare for birth
abortion vs fetal death
abortion is loss before 20 weeks (spontaneous or induced)
fetal death is after 20 weeks
what are the 5 features tested for in the APGAR score
- heart rate
- respiratory effort
- muscle tone
- stimulation response
- skin coloration
tested at 1 minute and 5 minutes after birth
what are the 3 hormones that prepare breasts for lactation?
estrogen
progesterone
prolactin
papilla
nipple
location of lactiferous duct convergence
3 major milestones of embryonic development
nervous system - week 3
heart/blood vessels - week 2
heartbeat - week 4
when do males have primitive testes and started to secrete testosterone?
month 2
when does the most rapid growth occur?
2nd trimester
what is a normal birth weight?
2.7-4.5 kg or 6-10 lb
factors triggering labor
- stretching of uterine muscle stimulates prostaglandin production
- pressure on cervix stimulates oxytocin release
- changes in placenta that occur naturally
- cortisol from fetal adrenal cortex inhibits mother’s progesterone production (causes relative increase in estrogen stimulating uterine contractions)
what does oxytocin do
released from posterior pituitary
stimulates uterine contractions and uterine muscle becomes increasingly sensitive to it throughout pregnancy
works in positive feedback loop
explain the positive feedback loop of oxytocin
cervical stretching activates stretch receptors in uterine wall
these receptors send signals to posterior pituitary to release oxytocin
oxytocin stimulates further contractions of uterine muscle opening cervix further
continues until child is born and stimulus removed
pictocin
synthetic form of oxytocin that can be used to hasten labor
partuition
process by which fetus is expelled from the uterus
ends when bleeding is controlled
describe the first stage of labor
- onset of regular uterine contractions and cervix dilation
- cervix becomes thinner with each contraction and further dilation
- rupture of amniotic sac can occur at any time
describe the second stage of labor
- cervix completely dilated
- ends with baby’s birth
episiotomy may be performed to prevent tears
describe the third stage of labor
- begins after child is born
- ends with expulsion of afterbirth and bleeding control
what is contained in the afterbirth
placenta, amniotic sac, umbilical cord
placenta previa
placenta attaches at/near cervix
dilation near end of pregnancy can cause separation and fatal drop in O2 supply
abruptio placentae
placenta separates prematurely from uterine wall
common in multigravidas
may require termination to save mother’s life
placenta accreta
endometrium does not develop properly and placenta attaches to myometrium
can cause fatal post-natal bleeding
hyatidiform mole
arises from union of abnormal gametes or fertilization of ovum with 2 sperm cells
causes benign grape-like cyst growth that can turn into malignant choriocarcinoma
gestational diabetes
diabetes first diagnosed during pregnancy
hormone hPL appears to play role (induces insulin resistance in mother to spare glucose for fetus)
puerperal infections
infections related to birth
prevalence has dropped with antibiotics and more sterile techniques
ductal carcinoma in situ (DCIS)
precancerous condition originating in milk ducts
cannot be felt, have to be diagnosed with mammography
