Deck 12: Development of the Respiratory System and Body Cavities

Question 1

In tissue recombination experiments in culture it has been shown that branching morphogenesis of the lung involves epithelial-mesenchymal interactions.What is the source of the lung epithelium?

A) Ectoderm
B) Somatic mesoderm
C) Splanchnic mesoderm
D) Somitic mesoderm
E) Endoderm

Answer 1

E

Question 2

A mouse exhibiting congenital diaphragmatic hernia was produced by ENU mutagenesis.What gene was mutated in this mouse?

A) Fgf8
B) HoxB1
C) Shh
D) Fog2
E) Vegfr

Answer 2

D

Question 3

A baby with a severe diaphragmatic hernia with herniation of visceral into the pleural cavity also has other anomalies of the respiratory system.What anomaly is likely to be present?

A) Pulmonary agenesis
B) Pulmonary hypoplasia
C) Pulmonary hyperplasia
D) Tracheoesophageal fistula
E) Hyaline membrane disease

Answer 3

B

Question 4

A premature baby,born at 30 weeks,is suffering from respiratory distress.What stage of lung development would the lungs have reached at the time of delivery?

A) Alveolar
B) Saccular
C) Pseudoglandular
D) Canalicular
E) Embryonic

Question 5

Branching of the Drosophila tracheal system involves three genes,Branchless,Breathless,and Sprouty,and orthologs of these genes play similar roles in vertebrate lung development.What would be the expected outcome if Sprouty is inactivated during Drosophila development?

A) The tracheal system fails to form.
B) Extra branching of the tracheal system occurs.
C) Less branching of the tracheal system occurs.
D) The tracheal system is converted into a nervous system.
E) The tracheal system is converted into muscle.

Question 6

Pulmonary hypoplasia is often associated with which prenatal condition?

A) Polyhydramnios
B) Oligohydramnios
C) Cleft lip
D) Cleft palate
E) Spina bifida aperta

Question 7

Transgenic and gene targeting approaches have played important roles in understanding lung development and branching morphogenesis.Using this approach,Fgf signaling was blocked in the developing respiratory tree.What was the outcome of this experiment?

A) Lungs were not induced.
B) Tracheoesophageal fistula occurred.
C) Esophageal atresia occurred.
D) Lungs failed to undergo branching morphogenesis.
E) Cystic fibrosis occurred postnatally.

Question 8

A premature baby is not producing sufficient surfactant.What is known to stimulate surfactant synthesis prior to birth?

A) Testosterone
B) Estrogen
C) Progesterone
D) Thyroxine
E) FSH and LH

Question 9

An embryologist is studying the development of the phrenic nerve in human embryos.He reads that these nerves course through tissues involved in coelom partitioning.What is this tissue?

A) Pleuropericardial fold
B) Pleuroperitoneal membrane
C) Septum transversum
D) Ventral and lateral body wall
E) Esophageal mesoderm

Question 10

A medical student is confused when learning that the muscle of the diaphragm is innervated by the phrenic nerves,based on the level of origin of these nerves from the CNS.What is the explanation of how this innervation occurs during embryogenesis?

A) The phrenic nerves arise in the cervical region in association with the septum transversum and cervical myotomes, and as the myotomes migrate more caudally, they carry their innervation with them.
B) The muscle of the diaphragm arise late in development and cannot grow back to the thoracic spinal cord because the spinal nerves have already formed at this level, so they grow more cranially to the cervical region.
C) The thoracic nerves initially supplying the diaphragm die during development and are replaced by new nerves that grow from the cervical region.
D) The muscle of the diaphragm arises from the thoracic myotomes but secretes a chemoattractant that specifically attracts cervical spinal nerves.
E) The muscle of the diaphragm arises from the thoracic myotomes but secretes a chemorepellent that specifically repels thoracic spinal nerves.