Chapter 4 - Prenatal Development and Birth Flashcards
Ovulation occurs after?
Estrogen release
When does the premenstrual period occur?
When estrogen and progesterone both drop dramatically
When is the best time to have sex for conception? Why is this?
On the days leading up to ovulation. Because these days have higher fertility levels.
What does BBT stand for?
basal body temperature
When does basal body temperature drop? When does it begin to rise again?
During the fertile window, and it drops even more on the day of ovulation. It begins to rise after ovulation.
How can someone test to see if ovulation is, in fact, occurring?
They can map out several cycles. If there isn’t a sustained rise in basal body temperature (10-12 days), ovulation may not be occurring.
Conception and Implantation process
Day 0 - fertilization, we now have a zygote
Day 1 - first cleavage
Day 2 - 2-cell stage then 4-cell stage
Days 3-4 - 8 cell compacted morula
Day 5 - Early blastocyst (inner cell mass will become embryo, outer cell mass will become placenta)
Day 6-7 - Late stage blastocyst (hatching), around the cell forms a thing called zona pellucida
Day 8-9 - implantation of the blastocyst
Cleavage
Cell division during early early development
Morula
8-cell mass in spherical form, 3-4 days post fertilization
Blastocyst
Cell mass with a cavity 4-5 days post fertilization. Contains inner mass (will become embryo) and outer mass (will become placenta)
Implantation
Beginning about 1 week post conception. The burrowing of the organism into the uterine lining where it is nourished
Germinal period
the first 2 weeks of development after conception
After a week of conception, the cell mass, now called a blastocyst, forms two distinct parts - a shell that will become the placenta and a nucleus that will become the embryo
First task: Implantation which is the process, beginning about 10 days after conception, in which the developing organism burrows into the placenta that lines the uterus, where it can be nourished and protected as it continues to develop
Embryonic Period
the 3rd to 8th week after conception
Formless mass of cells becomes a distinct being
This is when it becomes an embryo which is the name for a developing human organism from about the third through the either week of conception
Fetal Period
from the end of the embryonic period until birth (the 9th week - birth)
When is pregnancy established?
Once the embryo (conceptus) has implanted into the uterus
What does hCG stand for?
Human chorionic gonadotropin
What does human chorionic gonadotropin block?
Regression of the corpus luteum, therefore mensturation does not occur
What does a pregnancy test test for? Why?
Human chorionic gonadotropin, because only a developing embryo can produce this
What % of pregnancy ends in live birth?
80%
What % chance that the baby will survive infancy?
> 90%
What % of human embryos are genetically abnormal and have little to no chance of giving rise to a viable (able to live after birth) child?
> 50%
What do half of miscarriages have? What percentage of live birth has answer?
Chromosomal abnormalities. 0.5%
Ectopic Pregnancy? % that this occurs?
Location of implantation other than the uterus, 1%
What is the most common site for ectopic pregnancies?
Oviducts
What do ectopic pregnancies lead to?
Miscarriage, can rupture and be life threatening
What is Rhesus (Rh) incompatibility?
When the mother is not compatible with rhesus
What happens if the mother is Rhesus incompatible?
She develops antibodies against Rh and antibodies cross the placenta and attack the fetus
Why does a mother’s Rhesus incompatibility affect only her second, third and so on pregnancy?
Because in order for it to affect her, her baby’s (who posseses Rh) blood would have to mix with her. This happens when she gives birth, and she gets the shot right after, so the antibodies don’t have time to develop fast enough to attack the placenta.
What shot do Rhesus incompatible mothers receive after their first birth? What does this shot do?
Rh-specific immunoglobin, it binds to the Rh and ‘hides’ it from the maternal immune system
Why would a Rhesus incompatible mother have to receive her shot before she gives birth if she gets into an accident?
Because the baby’s and mother’s blood might have a chance to mix.
Where is Rhesus (Rh) located?
The surface of red blood cells
Primiparous
A pregnant women who has not given birth or only given birth once
Multiparous
A pregnant woman who has given birth more than once
Gestational Age
Fetal age given from the time of ovulation
Menstrual Age
Fetal age given from the onset of the last menstrual period, which is 14 days before conception
Which age is inaccurate? Menstrual or gestational? Why?
Menstrual, because the doctor asks you when your last period was, and tells you how long you’ve been pregnant, when you’re actually 2 less weeks pregnant than your doctor claims.
What % of babies are born on their due date?
5%
Pregnancy cannot be confirmed until ____
Implantation
How many more calories should a pregnant woman consume than usual?
300 calories
Where do the extra 300 calories consumed by a pregnant mother go to?
Most goes towards extra energy for fetal development and the rest goes to fat accumulation
Why does a fetus need a fresh supply of calories daily?
Because it cannot survive off maternal fat deposit
Around how much weight does a pregnant woman gain?
25-35 pounds
What does a mother ingesting folic acid do to her child?
The child might have Spina Bifida (neural tube defect where bones of the spine don’t form properly around part of the baby’s spinal cord)
What does a mother ingesting vitamin A and D do to her child?
The child might be retarded
During embryo development (3-8 weeks) how many layers does the developing organism begin differentiating into?
3
Neural tube
A fold of outer embryonic cells that appears about the 3 weeks after conception and later develops into the central nervous system
What week does the head start to take shape?
4th
What does a blood vessel become in the 4th week?
The heart
Neural plate
-A primitive neural tissue- occupies that outermost layer of the embryonic cell
Neural groove
The neural plate folds to form the neural groove
Anterior neural fold
When this closes, it forms the brain
Process of gross development?
A primitive neural tissue (neural plate) occupies the outermost layer of the embryonic cell. The neural plate folds to form the neural groove. The neural groove curls to form the neural tube. The anterior neural fold closes to form the brain.
Sex organs are identical, and only begin to take shape in the __rd month
3rd
Through the 7th week, males and females are ____
identical
By __th week external genitalia are formed
12th
Newly formed sex organs will begin to send ____ to the developing brain, directing small variations.
hormones
By end of 3rd month, fetus has all its bodily parts. How much does it weigh, and how long is it? At this stage, the placenta is fully ____
3 ounces and 3 inches
formed
Meconium?
Fills the digestive system of fetuses, kind of like sticky tar
What happens in the middle 3 months?
Digestive system develops
finger and toe nails, teeth buds, hair and eyelashes
Extreme brain growth – and begins to react to stimuli
What happens to the brain at 28 weeks?
brain wave patterns shift from a flat pattern to occasional bursts of activity (sleep-wake cycles)
At 28 weeks and 3 pounds, what are the chances of survival?
95%
Brain weight (g) 20 weeks gestation Birth 18 months 3 years Adult
100 400 800 1100 1300-1400
Genes and ____ interact throughout brain development
environment
Genes form neurons and make ____ among major brain regions
connections
Anatomy is programmed by our genes but there is some fine tuning done by _____ and ____. Enhancing connections while ____ others.
Experience, environment
Eliminating