NU 404 Unit 3 Fetal Development, Genetics, and Pregnancy
Exam Test Questions with All Correct Answers.
Fetal Development - Ans-During pregnancy is measured by the number of weeks after
fertilization.
Pregnancy is divided into three trimesters.
How long is human pregnancy? - Ans-An average human pregnancy lasts for 40 weeks
from the date of the last menstrual period.
Calculated as 10 lunar months or 9 months by the modern calendar.
3 Trimesters of Pregnancy - Ans-1st Trimester - (Months 0-3) (Weeks 0-13) Rapidly
dividing at a quick pace. Undergoing cell division.
2nd Trimester (Months 3-6) (Weeks 14-27) Fetal development is in full gear developing
the brain, cardiovascular system, etc.
3rd Trimester (Months 6-9) (Weeks 28-42) Baby gaining weight, organ systems have
developed.
3 Stages of Fetal Development - Ans-Preembryonic Stage - fertilization through the 2nd
week (sperm and egg meet = zygote) (massive cell division) (1st trimester)
Embryonic Stage - end of the 2nd week through the 8th week (still in first trimester)
Fetal Stage - end of the 8th week until birth (longest stage)
Preembryonic Stage - Ans-The pre embryonic stage begins with fertilization (takes place
in the distal part of the fallopian tube), also called conception. This stage begins when egg
and sperm unite and is also when we can find out if we are having a girl or boy.
The gametes (ovum or sperm cells) must each have a set of 23 chromosomes.
,Come together to form the zygote (implants and burrows into endometrium), (combined to
form a total of 46 chromosomes). Any variation with chromosomes causes defects.
Sex determination and genetic information is determined at fertilization and depends on
whether the ovum is fertilized by a Y-bearing sperm (boy) or an X-bearing sperm (girl).
An XX zygote will become a female, and an XY zygote will become a male. Genetic
testing can be performed to see X or XY.
Preembryonic Stage: Twins - Ans-Identical Twins (also called monozygotic twins) occur
when one fertilized egg splits and develops into two. Identical twins have the same genes
so they generally look alike and are the same sex.
Fraternal Twins (also called dizygotic twins) develop when two separate eggs are
fertilized by two different sperm. Similar to other siblings, fraternal twins share about 50%
of their genes, so they can be different sexes and look different.
Implantation - Ans-Occurs during the Pre Embryonic Stage. Normally, implantation occurs
in the upper uterus (fundus), where a rich blood supply is available.
Embryonic Stage - Ans-The stage of when zygote has multiplied and divided into an
embryo.
The embryonic stage of development begins at day 15 after conception and continues
through week 8.
Basic structures of all major body organs and the main external features are completed
during this time period including internal organs.
The chorion outermost membrane of embryo.
During this stage, the amnion originates and is a thin protective membrane over the
embryo that contains amniotic fluid.
2 week to 8 week mark when face, major organs, body structures start to develop.
Chorion - Ans-Outermost membrane that forms and protects the baby, also protects
amniotic fluid.
, Amnion - Ans-Innermost membranous sac surrounding the developing fetus. Inside of this
is amniotic fluid. When you hear the term "water breaks" that is the amniotic fluid.
Dichorionic-Diamniotic DI-DI - Ans-Each baby has their own sac, one placenta, own blood
supply, their own cord. BEST SITUATION. Twins can be high risk but this is the ideal
situation. Two amnions, two chorions.
Monochorionic-Diamniotic MO-DI - Ans-Twins that share a placenta and therefore a blood
supply but have their own amniotic sac.
Separate amnions within the same outer membrane and one single, shared placenta.
Two bags and one chorion. Placenta grows off of the chorion, but there are two sacs.
Monochorionic-Monoamniotic MO-MO - Ans-One chorion, one amnion, and one placenta.
Identical twins. Risk is due to taking blood supply from sibling. Chances of a fetal accident
with umbilical cords is HIGH risk. MOMO or monomono. Very rare.
Fetal Stage - Ans-The fetal stage is the time from the end of the 8th week until birth.
It is the longest period of prenatal development.
During this stage, the embryo is mature enough to be called a fetus.
Although all major systems are present in their basic form, dramatic growth and
refinement of all organ systems take place during the fetal period.
Amniotic Fluid - Ans-amniotic fluid surrounds the embryo and increases in volume as the
pregnancy progresses, reaching approximately a liter at term.
Amniotic fluid is derived from two sources; fluid transported from the maternal blood
across the amnion (innermost membrane that encloses the embryo) and fetal urine.
Volume changes constantly as fetus swallows and voids.
Exam Test Questions with All Correct Answers.
Fetal Development - Ans-During pregnancy is measured by the number of weeks after
fertilization.
Pregnancy is divided into three trimesters.
How long is human pregnancy? - Ans-An average human pregnancy lasts for 40 weeks
from the date of the last menstrual period.
Calculated as 10 lunar months or 9 months by the modern calendar.
3 Trimesters of Pregnancy - Ans-1st Trimester - (Months 0-3) (Weeks 0-13) Rapidly
dividing at a quick pace. Undergoing cell division.
2nd Trimester (Months 3-6) (Weeks 14-27) Fetal development is in full gear developing
the brain, cardiovascular system, etc.
3rd Trimester (Months 6-9) (Weeks 28-42) Baby gaining weight, organ systems have
developed.
3 Stages of Fetal Development - Ans-Preembryonic Stage - fertilization through the 2nd
week (sperm and egg meet = zygote) (massive cell division) (1st trimester)
Embryonic Stage - end of the 2nd week through the 8th week (still in first trimester)
Fetal Stage - end of the 8th week until birth (longest stage)
Preembryonic Stage - Ans-The pre embryonic stage begins with fertilization (takes place
in the distal part of the fallopian tube), also called conception. This stage begins when egg
and sperm unite and is also when we can find out if we are having a girl or boy.
The gametes (ovum or sperm cells) must each have a set of 23 chromosomes.
,Come together to form the zygote (implants and burrows into endometrium), (combined to
form a total of 46 chromosomes). Any variation with chromosomes causes defects.
Sex determination and genetic information is determined at fertilization and depends on
whether the ovum is fertilized by a Y-bearing sperm (boy) or an X-bearing sperm (girl).
An XX zygote will become a female, and an XY zygote will become a male. Genetic
testing can be performed to see X or XY.
Preembryonic Stage: Twins - Ans-Identical Twins (also called monozygotic twins) occur
when one fertilized egg splits and develops into two. Identical twins have the same genes
so they generally look alike and are the same sex.
Fraternal Twins (also called dizygotic twins) develop when two separate eggs are
fertilized by two different sperm. Similar to other siblings, fraternal twins share about 50%
of their genes, so they can be different sexes and look different.
Implantation - Ans-Occurs during the Pre Embryonic Stage. Normally, implantation occurs
in the upper uterus (fundus), where a rich blood supply is available.
Embryonic Stage - Ans-The stage of when zygote has multiplied and divided into an
embryo.
The embryonic stage of development begins at day 15 after conception and continues
through week 8.
Basic structures of all major body organs and the main external features are completed
during this time period including internal organs.
The chorion outermost membrane of embryo.
During this stage, the amnion originates and is a thin protective membrane over the
embryo that contains amniotic fluid.
2 week to 8 week mark when face, major organs, body structures start to develop.
Chorion - Ans-Outermost membrane that forms and protects the baby, also protects
amniotic fluid.
, Amnion - Ans-Innermost membranous sac surrounding the developing fetus. Inside of this
is amniotic fluid. When you hear the term "water breaks" that is the amniotic fluid.
Dichorionic-Diamniotic DI-DI - Ans-Each baby has their own sac, one placenta, own blood
supply, their own cord. BEST SITUATION. Twins can be high risk but this is the ideal
situation. Two amnions, two chorions.
Monochorionic-Diamniotic MO-DI - Ans-Twins that share a placenta and therefore a blood
supply but have their own amniotic sac.
Separate amnions within the same outer membrane and one single, shared placenta.
Two bags and one chorion. Placenta grows off of the chorion, but there are two sacs.
Monochorionic-Monoamniotic MO-MO - Ans-One chorion, one amnion, and one placenta.
Identical twins. Risk is due to taking blood supply from sibling. Chances of a fetal accident
with umbilical cords is HIGH risk. MOMO or monomono. Very rare.
Fetal Stage - Ans-The fetal stage is the time from the end of the 8th week until birth.
It is the longest period of prenatal development.
During this stage, the embryo is mature enough to be called a fetus.
Although all major systems are present in their basic form, dramatic growth and
refinement of all organ systems take place during the fetal period.
Amniotic Fluid - Ans-amniotic fluid surrounds the embryo and increases in volume as the
pregnancy progresses, reaching approximately a liter at term.
Amniotic fluid is derived from two sources; fluid transported from the maternal blood
across the amnion (innermost membrane that encloses the embryo) and fetal urine.
Volume changes constantly as fetus swallows and voids.
