10.1 Development of Midline Structures

Question 1

Where is the pituitary gland located?

Answer 1

Pituitary fossa

Question 2

What are the different functions of the two lobes?

Answer 2

Anterior (endocrine)

Posterior (neuroendocrine)

Question 3

What is the first stage of pituitary gland formation?

Answer 3

Out-growth of forebrain called the infundibulum

Question 4

What is the second stage of pituitary gland formation?

Answer 4

Rathke’s pouch formation. Invagination of the oropharynx which grows towards the infundibulum

Question 5

What does Rathke’s pouch become?

Answer 5

Anterior pituitary

Question 6

What does the infundibulum become?

Answer 6

Posterior pituitary and stalk

Question 7

Which parts of the tongue does the 1st pharyngeal arch contribute to?

Answer 7

2 lateral lingual swellings and tuberculum impar

Question 8

Which parts of the tongue does the 2nd and 3rd pharyngeal arches contribute to?

Answer 8

Cupola

Question 9

Which parts of the tongue does the 4th pharyngeal arch contribute to?

Answer 9

Epiglottal swelling

Question 10

What happens to the arch derivatives as the tongue starts to develop?

Answer 10

Lateral lingual swellings grow over tuberculum impar
3rd pharyngeal arch component of cupola grows over 2nd arch component
Extensive degeneration to free the tongue from the floor of the oral cavity

Question 11

Which nerves supply general sensory innervation to the anterior 2/3rds of the tongue?

Answer 11

Trigeminal and Glossopharyngeal

Question 12

Which nerves supply general sensory innervation to the posterior 1/3rds of the tongue?

Answer 12

Glossophayngeal and Vagus

Question 13

What nerve innervates the taste buds in the tongue?

Answer 13

Chorda tympani

Question 14

Which nerve innervates the muscles of the tongue?

Answer 14

Hypoglossal

Question 15

Where does the primordium of the thyroid gland appear?

Answer 15

Floor of the pharynx between tuberculum impar and cupola

Question 16

What connects the thyroid gland to the tongue as it descends through the neck?

Answer 16

Thyroglossal duct

Question 17

Where does the thyroid end up?

Answer 17

Pouch of 4th pharyngeal arch

Question 18

What is 1st arch syndrome?

Answer 18

Spectrum of defects in the development of 1st arch derivatives. Failure of colonisation of 1st arch with neural crest cells

Question 19

List the symptoms of CHARGE syndrome

Answer 19

C- coloboma 
H- heart defects
A- choanal atresia
R- retardation 
G- genital hypoplasia
E- ear defects