Ch. 10- Fetal Development&Genetics Flashcards
After 9 weeks, the embyro is known as what?
The fetus
The heart begins beating around what week?
Week 3
When is the sex of the embryo determined? Which chromosome of the parents are determining this?
At conception- Fertilization.
- The father’s Y chromosome determines sex of the baby
Which hormone produced by the placenta is an antagonist to insulin, making it responsible for gestational diabetes?
Human placental lactogen (hPL) or Human chorionic somatomammotropin (hCS)
Medical age of viability is typically?
21 weeks. Roughly 400g. Able to still be intubated and resuscitated
What hormone is a smooth muscle relaxant that prevents contraction and disruption of blood flow after embryo implantation?
Progesterone
The umbilical cord has how many blood vessels?
3
Wharton Jelly composes the?
Umbilical cord
What helps muscular development of the fetus?
Fetal movement within the uterus
The umbilical vein carries __________ blood from _________ to _________.
oxygenated blood and nutrients from the placenta to the developing fetus.
How early can ________ ______ genetic testing be done to determine the fetus’ risk for sickle cell anemia?
- Chorionic villus
- 10 weeks
Sufficient amounts of amniotic fluid throughout pregnancy support what?
Fetal movement and musculoskeletal development
Trisomy 13 is also known as ________ _________. What is the prognosis?
Patau’s syndrome. Life expectancy is a few days.
How would you describe mosaicism?
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.
How would you describe the trophoblast?
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.
An example of a congenital autosomal recessive disorder is?
-Tay-Sachs disease is an example of an autosomal recessive disorder.
-Neurofibromatosis, achondroplasia, and Huntington disease are examples of autosomal dominant disorder.
Clamping the umbilical cord will trigger what response in the fetal heart?
The ductus venosus will close.
The foramen ovale will close when?
The foramen ovale closes within 1 to 2 hours after birth and permanently by 6 months.
What changes will occur to the ductus arteriosus after birth?
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.
When is quad screening testing done?
16 weeks
What does the mesoderm form?
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.
Which hormone is responsible for uterine contractility?
Progesterone maintains the endometrium, decreases uterine contractility, stimulates maternal metabolism and breast development, and provides nourishment for the early conceptus.
The ectoderm will form what?
The ectoderm forms the structures of the special senses. Ie: eyes and ears
Which trisomy is uncommon?
10
Which hormone will ensure that embryonic implantation takes place?
hCG that is responsible for ensuring the endometrium is receptive to the implanting embryo.
What structures are present at 13 weeks? (Hint: related to extremities)
Fingernails and toenails
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?
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.
By 16 weeks, the fetus will:
- Have Fingernails and toenails
- Have fine hair on the head (lanugo)
- Make sucking movements
Which genetic condition is considered an autism-spectrum disorder?
-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.
Polyploidy is typically associated with?
Spontaneous abortion
In what time frame will most shunts close after birth?
3-4 weeks
What is the prognosis of trisomy 10?
Poor. Most spontaneously abort, or 30 days to 5 years if live birth.
