Question 1

At what gestational age are as many as 75 percent of the conducting airways developed?

Accepted Answer

B

Question 2

How many alveoli would be expected in a 12-year-old child?

Accepted Answer

By the age of 8, it's estimated that the lungs have already reached their adult count of alveoli, which is more than 300 million. Therefore, a 12-year-old would have more than 240 million alveoli, aligning with option D.

Question 3

Which of the following would be most likely to develop after delivery of a newborn at 27 weeks gestational age?

Accepted Answer

PPHN (Persistent Pulmonary Hypertension of the Newborn) is more likely to develop in newborns delivered prematurely, such as at 27 weeks gestational age, due to the underdevelopment of the lungs and pulmonary vasculature.

Question 4

At what gestational age after fertilization are all major bronchi present?

Accepted Answer

The answer of At what gestational age after fertilization are...

Question 5

Which of the following contribute to the wide variance between maternal and fetal P_O₂ and P_CO₂? I. The placenta is an actively metabolizing organ II. Regional variations occur in placental permeability III. Maternal and fetal vascular shunts occur

Accepted Answer

The wide variance between maternal and fetal blood gases is influenced by all three factors: the placenta's active metabolism, variations in placental permeability, and the presence of maternal and fetal vascular shunts. These elements collectively ensure efficient gas exchange and nutrient transfer between mother and fetus.

Question 6

At what gestational age does the terminal saccular period begin?

Accepted Answer

The answer of At what gestational age does the terminal...

Question 7

In a full-term newborn, how many alveoli are present at birth?

Accepted Answer

At birth, a full-term newborn has approximately 24 million alveoli. The number of alveoli increases significantly after birth, reaching adult numbers by around 8 years of age.

Question 8

At what gestational age does the placenta begin to develop?

Accepted Answer

The placenta begins to develop at the time of implantation of the fertilized egg, which typically occurs around day 6-7 after fertilization.

Question 9

Where does fetal lung fluid originate?

Accepted Answer

Fetal lung fluid is produced by the alveolar cells of the fetus's lungs, not from external sources or other bodily fluids. This fluid plays a crucial role in lung development.

Question 10

What of the following influence the oxygen transfer from maternal to fetal blood? I. Maternal-fetal PO₂ gradient II. Higher hemoglobin concentration in fetal blood III. Lower affinity of HbF for oxygen

Accepted Answer

I. The maternal-fetal partial pressure gradient of oxygen (PO2) is crucial for oxygen transfer from the mother to the fetus. A higher PO2 in maternal blood compared to fetal blood drives the diffusion of oxygen across the placenta.II. Fetal blood has a higher hemoglobin concentration than maternal blood, which allows it to carry more oxygen per unit volume. This adaptation helps the fetus obtain sufficient oxygen from the maternal blood.III. Fetal hemoglobin (HbF) actually has a higher affinity for oxygen than adult hemoglobin (HbA), not lower. This higher affinity allows HbF to effectively extract oxygen from maternal blood, where the oxygen is bound to HbA with lower affinity.

Question 11

At what gestational age do primitive respiratory bronchioles appear?

Accepted Answer

Primitive respiratory bronchioles appear during the pseudoglandular stage of lung development, which occurs approximately between 5 to 17 weeks of gestation. However, the specific timeframe for the appearance of primitive respiratory bronchioles is generally placed within the range of 17-26 weeks, marking the transition into the canalicular stage, where the lung structures become more refined and capable of supporting gas exchange if birth occurs prematurely.

Question 12

What is the term for the premature separation of the placenta from the uterine wall?

Accepted Answer

Abruptio placentae is the medical term for the premature separation of the placenta from the uterine wall, which can lead to bleeding and complications for both the mother and baby.

Question 13

Which vessels transports oxygenated blood and nutrients from the placenta to the fetus?

Accepted Answer

The umbilical vein is responsible for carrying oxygenated blood and nutrients from the placenta to the fetus, providing the necessary components for fetal development.

Question 14

After birth, into what structure does the umbilical vein evolve?

Accepted Answer

The umbilical vein, which carries oxygenated blood from the placenta to the fetus, transforms into the ligamentum teres (round ligament) of the liver after birth, when it becomes non-functional due to the baby starting to breathe air and no longer receiving blood from the placenta.

Question 15

How is fetal lung fluid normally removed?
I. Squeezed out during vaginal delivery
II. Absorbed by the pulmonary capillaries
III. Absorbed by the lymphatic system
IV. Removed by vigorous endobronchial suctioning by the delivery room staff

Accepted Answer

Fetal lung fluid is removed through a combination of being squeezed out during vaginal delivery, absorption by the pulmonary capillaries, and absorption by the lymphatic system. Vigorous endobronchial suctioning is not a normal mechanism for the removal of fetal lung fluid.

Question 16

Which of the following structures would compose the placental cotyledons?
I. Fetal vessels
II. Chorionic villi
III. Intervillous spaces

Accepted Answer

Placental cotyledons are composed of fetal vessels, chorionic villi, and intervillous spaces, all of which play crucial roles in nutrient and gas exchange between the mother and fetus.

Question 17

What is the term for the procedure in which a sample of the fluid surrounding a fetus is removed via a needle inserted through the uterine wall and the fluid sample is analyzed for abnormalities?

Accepted Answer

Amniocentesis is the procedure where a small amount of amniotic fluid, which surrounds the fetus, is extracted through the uterine wall using a needle for the purpose of genetic and chromosome testing.

Question 18

What is the normal P_O₂ in the umbilical arteries?

Accepted Answer

The normal partial pressure of oxygen (PS1U1B1O2) in the umbilical arteries is approximately 20 mm Hg, reflecting the lower oxygen content in the fetal blood returning to the placenta.

Question 19

In the fetus, where does the majority of blood flow go after leaving the right atrium?

Accepted Answer

In the fetus, the majority of blood flow bypasses the lungs and flows from the right atrium to the left atrium through the foramen ovale, a fetal circulatory structure, because the lungs are not yet in use for oxygen exchange.

Question 20

At what gestational age do lung buds first appear?

Accepted Answer

The answer of At what gestational age do lung buds...

Quiz 10: Fetal Development and the Cardiopulmonary System