Exam 17: Development of the Pharyngeal Apparatus and Face

The secondary palate forms by fusion of which processes?

The oropharyngeal membrane ruptures to create the continuity between the developing gut and oral cavity during which week of gestation?

The thyroid gland starts to produce circulating hormones during which weeks of gestation?

The third aortic arches lie between which pharyngeal grooves/clefts?

The third pharyngeal pouches lie between which pharyngeal arches?

A new mom takes her baby son on an airplane trip.On descent,the child begins to cry vociferously,and does not quiet down until a few minutes after landing.At the next well-baby visit,the pediatrician explains that the eustachian tube in infants is very short and horizontally oriented,resulting in difficulty in clearing pressure from the middle ear.The eustachian tube forms from a persisting portion of a pharyngeal pouch that remains connected to the pharynx.Which pharyngeal pouch forms the eustachian tube?

A child is diagnosed with DiGeorge syndrome due to a 22q11.2.1 deletion encompassing approximately 30 to 40 genes.Researchers have genetically inactivated these genes in mice to identify which are essential for pharyngeal arch development.Which two genes in the deleted area are now thought to be the key players in DiGeorge syndrome?

Fate mapping studies of neural crest cell migration have been carried out in chicks,quails,and mice.These studies have shown that the neural crest cells that populate the second pharyngeal arch arise from which level(s) of the brain?

Which signaling molecule patterns the cranial-caudal axis of the hindbrain?

A baby boy presents with Treacher Collins syndrome.A medical geneticist evaluates the boy and meets with both parents.She notices that the mother has mild Treacher Collins-like features.Which pharyngeal arch derivatives are most dramatically affected in this syndrome?

Craniosynostosis,the premature closure of the sutures,is usually due to increased signaling of which pathway?

A premature infant is examined by a neonatologist at University hospital.Based on its facial features and a maternal history,the child is diagnosed with fetal alcohol syndrome.Fetal alcohol syndrome most dramatically affects derivatives of which pharyngeal arches?

Which of the craniosynostosis syndromes is unusual in that it is X-linked,with females,but not males,being symptomatic?

Mutations in the growth factor SONIC HEDGEHOG would be expected to result in which birth defect?

Fontanelles allow deformation of the skull during birth.How many fontanelles are present at birth?

The superior parathyroid gland arises from which structure?

A researcher discovers a gene that when knocked out causes the most common form of cleft lip seen in humans.Examination of the expression of this gene in embryos shows that it is expressed in the facial prominences that flank the area of cleft lip formation.What are these flanking prominences?

The first pharyngeal arch forms on which day of gestation?

Researchers have shown that the Hox genes are important for patterning the pharyngeal arches.Which of the Hox genes is essential for the specification of the second pharyngeal arch and when genetically inactivated in mice,result in the homeotic transformation of the second pharyngeal arch into one with first pharyngeal arch identity?

A teenage boy who is taking Accutane® for severe acne meets a new girl at school and begins dating her.She too has acne,although mild,and asks her boyfriend to share his medicine with her.After a few weeks of dating they begin to have unprotected intercourse.Which embryonic cell population will be most endangered by Accutane® exposure if the girl becomes pregnant?