Pregnancy

Pregnancy & Embryonic Development

Question: What does prenatal development include?
Answer: Prenatal development includes fertilization, implantation in the uterus, cell divisions, embryo development, fetal development, maturation of fetal organ systems, and birth.

Question: What is gestation?
Answer: Gestation is the period of prenatal development.

Question: How long is human gestation?
Answer: Human gestation lasts about 40 weeks, or around 9 months.

Question: How is pregnancy divided?
Answer: Pregnancy is divided into 3 trimesters.

Question: How long is each trimester?
Answer: Each trimester lasts about 3 months.

Question: What happens during the first trimester?
Answer: The major germ layers are created, and the internal scaffolding of the embryo begins forming.

Question: What do germ layers give rise to?
Answer: Germ layers give rise to the major tissues of the body, including cardiovascular structures, skin, nervous tissue, and other tissues.

Question: What happens during the second trimester?
Answer: The major organs and organ systems continue developing, and the embryo starts to look more like a human body.

Question: What happens during the third trimester?
Answer: Significant body growth occurs, and the organs begin becoming functional.

Question: During which trimester is the embryo most vulnerable?
Answer: The first trimester is when the embryo is most vulnerable.

Question: About what percentage of conceptions survive the first trimester?
Answer: About 40% of conceptions survive during this period.

Question: When does the placenta develop?
Answer: The placenta develops during the first trimester.

Question: What physically connects the fetal body to the placenta?
Answer: The umbilical cord physically connects the fetal body to the placenta.

Question: Where is the placenta located?
Answer: The placenta is physically adjacent to the mother’s uterine wall.

Question: What is inside the umbilical cord?
Answer: The umbilical cord contains multiple blood vessels.

Question: How many umbilical veins are in the umbilical cord?
Answer: There is 1 umbilical vein.

Question: How many umbilical arteries are in the umbilical cord?
Answer: There are 2 umbilical arteries.

Question: What does the umbilical vein carry?
Answer: The umbilical vein carries oxygen-rich and nutrient-rich blood from the placenta into the fetal body.

Question: What do the umbilical arteries carry?
Answer: The umbilical arteries carry waste-filled and oxygen-poor blood out of the fetal body back to the placenta.

Question: Where do the umbilical blood vessels enter and exit the fetal body?
Answer: They enter and exit at the umbilicus, or belly button.

Question: What fetal organs have bypasses or shortcuts?
Answer: The fetal heart and liver have bypasses.

Question: What do the fetal heart bypasses allow blood to do?
Answer: They allow blood to largely bypass the fetal lungs.

Question: Why does fetal blood bypass the lungs?
Answer: The fetus is in a liquid environment and is not mechanically breathing, so gas exchange happens at the placenta instead of the lungs.

Question: Where does gas and nutrient exchange occur during fetal development?
Answer: Gas and nutrient exchange occurs at the interface between the uterine wall and the placenta.

Question: Why is it unnecessary to send a large amount of blood to the fetal lungs?
Answer: The fetal lungs are not being used for breathing before birth.

Question: What should happen to fetal bypasses after birth?
Answer: They should seal off after birth.

Question: What happens when fetal bypasses seal off after birth?
Answer: Blood is forced to enter the newborn’s lungs.

Question: What should I do with the question asking me to know the membranes around the fetal body?
Answer: Visual model/structure question noted and ignored.

Question: Which fetal membrane should you pay special attention to?
Answer: The amnion.

Question: What does the amnion do?
Answer: The amnion holds in the amniotic fluid surrounding the fetus.

Question: What does it mean when a pregnant woman’s “water breaks”?
Answer: It means the amnion has torn, allowing amniotic fluid to escape.

Question: What is the mucus plug?
Answer: The mucus plug forms at the base of the uterus.

Question: What is the function of the mucus plug?
Answer: It helps prevent bacteria from entering the uterus.

Question: What happens to the uterus as pregnancy progresses?
Answer: The uterus increases in size and length.

Question: What should I do with the question asking me to be familiar with physical changes in the uterus during pregnancy?
Answer: Visual model/slide-based question noted and ignored.

Question: What is the average weight of the uterus and its contents at full-term pregnancy?
Answer: At full term, the uterus and its contents weigh about 22 pounds on average.

Question: What happens to the mother’s digestive organs during pregnancy?
Answer: They remain active but are displaced upward because of the expanding uterus.

Question: What happens to the mother’s urinary bladder during pregnancy?
Answer: The expanding uterus pushes the bladder downward.

Question: Why do pregnant women often feel the urge to urinate frequently?
Answer: The expanded uterus presses down on the urinary bladder.

Question: What is the technical term for labor?
Answer: The technical term for labor is parturition.

Question: What does labor involve?
Answer: Labor involves strong, rhythmic contractions of the uterine wall.

Question: What is the goal of labor?
Answer: The goal of labor is expulsion of the fetus.

Question: How many stages of labor are there?
Answer: There are 3 stages of labor.

Question: What are the 3 stages of labor in order?
Answer: Dilation stage → expulsion stage → placental stage.

Question: What happens during the dilation stage?
Answer: The cervix dilates, and the amnion tears, which is commonly called water breaking.

Question: What happens during the expulsion stage?
Answer: The fetus emerges from the mother’s body.

Question: What happens during the placental stage?
Answer: The placenta emerges from the mother’s body.

Question: What is the placenta called after birth?
Answer: The placenta is called the afterbirth.

Question: What should I do with the question asking me to see pictures of the stages of labor?
Answer: Visual model/picture-based question noted and ignored.

Question: What is the first month after birth called?
Answer: The first month after birth is called the neonatal period.

Question: What happens to the lungs during the neonatal period?
Answer: The lungs fill with air.

Question: What happens to breathing during the neonatal period?
Answer: Breathing begins.

Question: What happens to the heart bypasses during the neonatal period?
Answer: The heart bypasses should slowly begin to seal shut.

Question: What should the newborn’s heart rate drop to?
Answer: The heart rate should drop to about 80–130 beats per minute.

Question: What happens to the digestive organs during the neonatal period?
Answer: The digestive organs start working.

Question: What happens to the kidneys during the neonatal period?
Answer: The kidneys become active and start filtering the blood.

Question: What happens to metabolism during the neonatal period?
Answer: Metabolism increases to help maintain adequate warmth for the newborn