tongue, thyroid and face

Question 1

what are pharyngeal arches

Answer 1

protrusions of mesenchyme at head end separated by pharyngeal clefts

become visible at -5 weeks

Question 2

what is a rhombomere

Answer 2

a divided segment of the developing neural tube within the hindbrain region in the area that eventually becomes the rhombencephalon

Question 3

what is the role of neural crest cells in developing pharyngeal arches

Answer 3

neural crest migration from the diencephalon, mesencephalon and rhombomeres of the hindbrain

• Transcription factors determine expression patterns into the pharyngeal arches
under control of endodermal signals
• Crest cells give rise to neurons supplying pharyngeal arches and
guide axons toward the CNS
• Arch mesoderm structures are derived from neural crest, lateral plate and paraxial mesoderm

Question 4

what is the first arch nerve

Answer 4

trigeminal, three divisions

Question 5

what is the 2nd arch nerve

Answer 5

facial

Question 6

what is the third arch nerve

Answer 6

glossopharyngeal

Question 7

what is the 4th and 6th arch nerve

Answer 7

vagus
4- superior laryngeal
6- recurrent laryngeal

Question 8

what does the cartilage of the 1st arch become

Answer 8

mandible and middle ear, malleus and incus (neural crest)

Question 9

what does the cartilage of the 2nd arch become

Answer 9

lesser horn of hyoid, styloid ligament and styloid, stapes

neural crest

Question 10

what does the cartilage of the 3rd arch become

Answer 10

greater horn of hyoid

neural crest

Question 11

what does the cartilage of the 4th and 6th arch become

Answer 11

thyroid and cricoid

lateral plate mesoderm

Question 12

what is the terminal sulcus made from

Answer 12

junction between 1st and 3rd arch mesenchyme

Question 13

what part of the tongue is made from the 1st arch

Answer 13

body

Question 14

what is the sensation supply of the anterior 2/3rds of the tongue

Answer 14

trigeminal (first arch)

Question 15

what is the sensation supply of the posterior third of the tongue

Answer 15

glossopharyngeal (3rd arch)

Question 16

what is the innervation of the epiglottis

Answer 16

4th arch- vagus, superior laryngeal

Question 17

what is the taste supply of the tongue

Answer 17

facial, glossopharyngeal, vagus

Question 18

what is the solitary nucleus

Answer 18

a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column of grey matter embeddedd in the medulla oblongata.

functions: taste, sensory from the ear, carotid and aortic body,

general visceral afferent pathway via vagus and glossopharyngeal nerves

Question 19

where does the thyroid originate

Answer 19

foramen caecum, caudal to the tuberculum impar

Question 20

where does the thyroid migrate to by week 7

Answer 20

anterior to hyoid and thyroid cartilages

Question 21

what is the thyroglossal duct

Answer 21

connects thyroid with tongue

Question 22

what can cause thyroid dysgenesis

Answer 22

mutations in transcription factors PAX8 and TITF1

Question 23

what do follicular cells in the thyroid secrete

Answer 23

triiodothyronine and thyroxine

Question 24

what do parafollicular cells produce

Answer 24

calcitonin

derived from the fourth pouch

Question 25

what is a thyroglossal cyst

Answer 25

remnant of thyroglossal duct
moves upwards on tongue protrusion
usually associated with the hyoid bone

Question 26

what is the stomodeum

Answer 26

a depression between the brain and pericardium in an embryo and is the precursor of the mouth and pituritary gland

Question 27

what structures are formed by the intermaxillary segment

Answer 27

philtrum, incisors, primary palate

Question 28

what does the palatine shelf form from

Answer 28

maxillary process

Question 29

what factors increase the likelihood of cleft lip/palate

Answer 29

Environmental
• Maternal age
• Medications antiepileptic agents or corticosteroids,
• Smoking
• Alcohol consumption during pregnancy
• Maternal illness was suggested to elevate the chance of CL/P
• Maternal diabetes
• Lack of dietary folic acid
Genetic
• Aberrant gene variants are inherited from mother or father
• Inheritance is variable, often not strictly Mendelian probably because of environmental factors

may be syndromic- treacher collins/ van de woude

Question 30

what are the effects of CL/CP

Answer 30

difficulty feeding, hearing and ear problems, speech problems, dental abnormalities, social and psychological