Ova
always contributes an X chromosome
Ovum
can survive up to 24 hrs after ovulation
Sperm
carries X or Y chromosome and can survive in the cervix for up to 5 days after ejaculation
Zygote
cell formed by the union of the sperm and the ovum, which is transported to the uterus through the fallopian tube;
IMPLANTS IN THE UPPER SECTION OF THE POSTERIOR UTERINE WALL
Fertilization of the zygote
usually occurs in the outer third of the fallopian tube
Blastomere
has 8 cells
Morula
solid ball of cells that begins on day 3 and lasts 2-4 days in the uterus
Blastocyst
inner layer of cells which develops into the embryo and embryonic membrane (chorion)
OCCURS ON THE 9TH DAY AFTER FERTILIZATION AND INITIATES THE PRODUCTION OF RED BLOOD CELLS UNTIL WEEK 6
Chorion
embryonic membrane; outer layer of embryonic cells that develops from the trophoblast (envelops the amnion, embryo, and yolk sac) has villi
Endometrium
prepared lining of the uterine wall in which the zygote burrows
Decidua
Endometrium becomes this after implantation
Decidua Basalis
area UNDER the blastocyst that gives rise to the maternal part of the placenta
Amnion
inner layer of the sac that protects the embryo and forms the boundaries of the amniotic cavity
Amniotic sac
Chorion and Amnion together form this filled with water
Amniotic fluid
clear with mild odor and bits of vernix; VOLUME AT 37 WEEKS = 1000 mL
Fetus may swallow up to
400 mL of amniotic fluid per day
Functions of the Amniotic Fluid are
Maintain even temperature
prevent sac from adhering to fetal skin
Allow symmetrical growth
Allows buoyancy and fetal movement
Acts as a cushion
Germ layers of zygote in blastocyst stage are
ectoderm, mesoderm and endoderm
Week 3 of embryo
single tubular
heart begins pumping
and neural tube forms; Mesoderm and primitive spinal cord and brain appear
Week 8 of embryo
distinct human appearance and purposeful movement occurs and SEX ORGANS form (genitalia is visible on ultrasound at week 10)
Week 17-20
Genitalia are visible on ultrasound and mother can feel movement
Week 20
fetus lungs are functionally mature and AGE OF VIABILITY
Gestational age of 25 weeks
we should try to heroically save and treat baby if born
Week 28 of Fetus
eyes open
Full term fetus
Weeks 38-40
Placenta
temporary organ for fetal respiration (oxygen), nutrition, and excretion - ALSO FUNCTIONS AS AN ENDOCRINE GLAND
TWO umbilical arteries
fetal deoxygenated blood and waste products leave the fetus and enter the placenta
ONE Umbilical Vein
Takes IN OXYGEN and nutrients returning to the fetus
Fetal hormones produced by the placenta
progesterone, estrogen, hCG and hPL
Progesterone
Maintains uterine lining
reduces uterine contractions (to prevent abortion)
prepares the glands of the breast for lactation
stimulates testes to produce testosterone
Estrogen
stimulates uterine growth
increases blood flow to the uterine vessels
stimulates breast DUCTS
skin pigments
stuffy nose
increased salivation
hCG
sends the signal to the corpus luteum that conception has occurred detectable in maternal blood as soon as 7-9 days after fertilization
Wharton's jelly
covers the cord vessels
hPL
causes decreased insulin sensitivity and utilization of glucose by the mother
Circulation of the blood through the placenta
is well established after the 4th week
Ductus Venous
diverts blood AWAY from the liver and returns it from the placenta
Foramen Ovale
diverts blood from the right atrium to the left atrium (opening between the atriums); this closes functionally w/in 2 hours after birth
Closes permanently by age 3 months
Ductus Arteriosus
diverts blood from the pulmonary Artery into the Aorta
Early Decelerations (in labor)
are the fetus's response to altered fetal cerebral blood flow and fetal head compression
Variable Decelerations (in labor)
are associated with umbilical cord compression
Late decelerations (in labor)
are associated with uteroplacental insufficiency
Latent first phase of labor
from the beginning of true labor until
4 cm
of cervical dilation
Active phase of labor
characterized by cervical dilation of
4 to 7 cm
Transition phase of labor
dilation from
7-10 cm
Second stage of labor
cervix is completely dilated until the birth of the baby
Third stage of labor
Expulsion of the placenta
Lochia Rubra
consists of blood and decidual debris and lasts for 3 days after birth
Lochia Serosa
pinkish tinged blood and mucus that lasts from days 3- 10 after birth
Lochia Alba
white mucus that lasts from days 10-21 after birth; should have no odor