Ch. 10- Fetal Development&Genetics

Question 1

After 9 weeks, the embyro is known as what?

Answer 1

The fetus

Question 2

The heart begins beating around what week?

Answer 2

Week 3

Question 3

When is the sex of the embryo determined? Which chromosome of the parents are determining this?

Answer 3

At conception- Fertilization.
- The father’s Y chromosome determines sex of the baby

Question 4

Which hormone produced by the placenta is an antagonist to insulin, making it responsible for gestational diabetes?

Answer 4

Human placental lactogen (hPL) or Human chorionic somatomammotropin (hCS)

Question 5

Medical age of viability is typically?

Answer 5

21 weeks. Roughly 400g. Able to still be intubated and resuscitated

Question 6

What hormone is a smooth muscle relaxant that prevents contraction and disruption of blood flow after embryo implantation?

Answer 6

Progesterone

Question 7

The umbilical cord has how many blood vessels?

Answer 7

3

Question 8

Wharton Jelly composes the?

Answer 8

Umbilical cord

Question 9

What helps muscular development of the fetus?

Answer 9

Fetal movement within the uterus

Question 9

The umbilical vein carries __________ blood from _________ to _________.

Answer 9

oxygenated blood and nutrients from the placenta to the developing fetus.

Question 10

How early can ________ ______ genetic testing be done to determine the fetus’ risk for sickle cell anemia?

Answer 10

• Chorionic villus
• 10 weeks

Question 11

Sufficient amounts of amniotic fluid throughout pregnancy support what?

Answer 11

Fetal movement and musculoskeletal development

Question 12

Trisomy 13 is also known as ________ _________. What is the prognosis?

Answer 12

Patau’s syndrome. Life expectancy is a few days.

Question 13

How would you describe mosaicism?

Answer 13

Mosaicism refers to when the chromosomal abnormalities do not show up in every cell and only some cells or tissues carry the abnormality. It occurs after fertilization and during the mitotic cell division. The symptoms are usually less severe.

Question 14

How would you describe the trophoblast?

Answer 14

The trophoblast forms the placenta and chorion. The blastocyst forms the embryo and amnion. The zygote is formed from the union of the sperm and ovum. The morula is a mass of 16 cells that develop as cleavage cell division continues after fertilization.

Question 15

An example of a congenital autosomal recessive disorder is?

Answer 15

-Tay-Sachs disease is an example of an autosomal recessive disorder.
-Neurofibromatosis, achondroplasia, and Huntington disease are examples of autosomal dominant disorder.

Question 16

Clamping the umbilical cord will trigger what response in the fetal heart?

Answer 16

The ductus venosus will close.

Question 17

The foramen ovale will close when?

Answer 17

The foramen ovale closes within 1 to 2 hours after birth and permanently by 6 months.

Question 18

What changes will occur to the ductus arteriosus after birth?

Answer 18

The ductus arteriosus constricts partly in response to the higher arterial oxygen levels that occur after the first few breaths. Functional closure of the ductus arteriosus in a term infant usually occurs within the first 72 hours after birth.

Question 19

When is quad screening testing done?

Answer 19

16 weeks

Question 20

What does the mesoderm form?

Answer 20

The mesoderm forms the skeletal (bones), urinary (kidneys), circulatory (heart), and reproductive organs. The ectoderm forms the central nervous system (brain), special senses, skin, and glands. The endoderm forms the respiratory system (lungs), liver, pancreas, and digestive system.

Question 21

Which hormone is responsible for uterine contractility?

Answer 21

Progesterone maintains the endometrium, decreases uterine contractility, stimulates maternal metabolism and breast development, and provides nourishment for the early conceptus.

Question 22

The ectoderm will form what?

Answer 22

The ectoderm forms the structures of the special senses. Ie: eyes and ears

Question 23

Which trisomy is uncommon?

Answer 23

10

Question 24

Which hormone will ensure that embryonic implantation takes place?

Answer 24

hCG that is responsible for ensuring the endometrium is receptive to the implanting embryo.

Question 25

What structures are present at 13 weeks? (Hint: related to extremities)

Answer 25

Fingernails and toenails

Question 26

A mother has come to the clinic with her 13-year-old daughter to find out why she has not started her menses. After a thorough examination and history, genetic testing is prescribed to r/o?

Answer 26

Turner syndrome is a common abnormality of the sex chromosome in which a portion or all of the X chromosome is missing. Only about one third of the cases are diagnosed as newborns; the remaining two thirds are diagnosed in early adolescence when they experience primary amenorrhea. No cure exists for this syndrome. Hormone replacement therapy may be used to induce puberty.

Question 27

By 16 weeks, the fetus will:

Answer 27

- Have Fingernails and toenails - Have fine hair on the head (lanugo) - Make sucking movements

Question 28

Which genetic condition is considered an autism-spectrum disorder?

Answer 28

-Fragile X syndrome. - It is common form of intellectual disability and autism spectrum disorder. Conservative estimates report that fragile X syndrome affects approximately one in 3,600 males and one in 6,000 females (National Fragile X Foundation, 2020). Typically, a female becomes the carrier and will be mildly affected. The male who receives the X chromosome that has a fragile site will exhibit the full effects of the syndrome.

Question 29

Polyploidy is typically associated with?

Answer 29

Spontaneous abortion

Question 30

In what time frame will most shunts close after birth?

Answer 30

3-4 weeks

Question 31

What is the prognosis of trisomy 10?

Answer 31

Poor. Most spontaneously abort, or 30 days to 5 years if live birth.