Unit 9: fetal development

Question 1

fertilization

Answer 1

The union of one egg and one sperm to create an embryo.
Happens in the Fallopian tubes.
Only possible within 24 hours of ovulation.

Question 2

Embryo

Answer 2

The fertilized egg. This term is used for the first few months of development. After that the embryo is referred to as the fetus.

Question 3

Implantation

Answer 3

When the embryo makes its home in the lining of the uterus. Happens about a week after fertilization.

Question 4

Why is the egg so much bigger than the sperm?

Answer 4

So that it can go through cell division many times, making hundreds of cells. The egg cell skips the G1 and G2 phases of the cell cycle because it is already so big.
honors: also because it got all the goods during meiosis

Question 5

Gastrulation

Answer 5

The formation of the gut (donut hole)

The first major development of the embryo.

Question 6

Which organs develop first? Why?

Answer 6

The placenta and umbilical cord, to nourish the fetus.
The heart, to pump nutrients around the body.
The liver, to manage any toxins.

Question 7

What is undeveloped in premature babies? Why?

premature babies are born after 6-8 months instead of 9 months

Answer 7

lungs: the fetus shouldn’t need to breathe yet, so they are undeveloped.
fat: the fetus should be warm inside mom, so it has not put on a layer of insulating fat under the skin yet.
Premies will be kept in an incubator to keep them warm and will be given pure oxygen to breathe.

Question 8

identical twins

Answer 8

One egg and one sperm made one embryo. During cell division, the embryo split into two bunches of cells and each developed into a baby.
Same DNA, so same bodies.

Question 9

fraternal twins

Answer 9

two eggs are ovulated (usually one from each ovary), both are fertilized, both implant. Results in non-identical twins.

Question 10

miscarriage

Answer 10

When the embryo or fetus is expelled from the mother’s body. Usually due to a problem with the fetus.

Question 11

placenta

Answer 11

The organ which allows the fetus’s blood to exchange nutrients and wastes with the mother’s blood
The placenta is directly attached to the uterus.
A tiny piece is taken to do CVS.

Question 12

amniotic sac

Answer 12

The bubble the baby is floating in.
Contains fluid to cushion the fetus.
The fetus practices breathing, swallowing and excreting this fluid.

Question 13

amniocentesis

Answer 13

A medical procedure used to get fetal skin cells. Some of the amniotic fluid is extracted using a needle.

Question 14

CVS

chorion villi sampling

Answer 14

A medical procedure used to get cells from the placenta (which contain the fetus’s DNA). The sample is taken using a tool which goes up the vagina, through the cervix, and into the uterus.

Question 15

conjoined twins

Answer 15

identical twins (always!) which did not fully separate.
Must be born surgically, by a C section.

Question 16

umbilical chord

Answer 16

the cord that connects the fetus to the placenta

Question 17

the after birth

Answer 17

The placenta
It is expelled a few minutes after the baby is born.
Usually it is thrown away by humans. Animal mothers eat the placenta, umbilical chord, and amniotic sac to regain nutrients and energy after giving birth.

Question 18

the birth canal

Answer 18

the vagina

Question 19

Is it ok to have sex while pregnant?

Answer 19

Yes. The baby is contained in the amniotic sac, so the sperm could not touch it. A woman does not ovulate while pregnant, so there is no egg cell for the sperm to fertilize. The movement will not hurt the baby.

Question 20

Which of the five senses develops first for a fetus?

Answer 20

Hearing develops first. The fetus can’t see, smell, taste, or touch, but it can hear voices and begins to learn language.

Question 21

Why do babies (and humans of all ages) calm down when they hear loud shushing and/or the sound of flowing water?

Answer 21

It is the sound of the blood moving though the mother’s body. It reminds us of safety and warmth.

Question 22

Why do babies (and humans of all ages) calm down with slow rhythms and get excited with fast rhythms?

Answer 22

The rhythms are similar to the sound of the mother’s heart beat. A slow heart beat is calm, while a racing heart is excited.

Question 23

lactation

Answer 23

The production of milk by the breasts.
Happens a few days after birth.
Breast milk is healthier for babies than formula.

Question 24

C section

Answer 24

A surgery in which doctors cut through the abdomen and uterus and remove the baby. sections can cause scarring of the uterus which might prevent the mother from having more babies. Natural birth healthier for babies.

Question 25

Ultrasound

Answer 25

The use of sound waves to gain an image of the fetus. By bouncing the sound waves off of the fetus, doctors can determine the sex of the baby (they look for a penis)
Ultrasound is also used in CVS and amniocentesis to ensure that the doctor’s tools do not harm the fetus.