Final

Question 1

From outer to inner (superficial to deep) what germ layers make up the pharyngeal arches?

Answer 1

ectoderm, mesoderm, endoderm

Question 2

How many pharyngeal arches, pouches, grooves (clefts) and (important) membranes are there?

Answer 2

5 arches (1,2,3,4,6)
4 pouches
4 grooves
1 membrane (b/w 1&2)

Question 3

What are the nerves of the pharyngeal arches in order?

Answer 3

1-5 (trigeminal- mandibular branch V3) 
2-7 (facial)
3-9 (glossopharyngeal)
4-10 (vagus- superior laryngeal branch)
6-10 (vagus- inferior (recurrent) laryngeal branch)

Question 4

Where do the cartilages from the pharyngeal arches come from?

Answer 4

1,2,3- neural crest

4&6- lateral plate mesoderm

Question 5

What are the skeletal derivatives of the pharyngeal arches?

Answer 5

1- malleus and incus, maxilla, and mandible
2- stapes, styloid process, and upper body of hyoid
3- greater horn and lower body of the hyoid
4- thyroid cartilage
6- cricoid cartilage

Question 6

What are the muscle derivatives of the pharyngeal cartilages?

Answer 6

1- muscles of mastication, mylohyoid, digastric, tensor palatini, tensor tympani
2- muscles of facial expression, scalp, ear, platysma, digastric, stylohyoid, stapedius
3- stylopharyngeus
4- cricothyroid
6- other muscles of pharynx, larynx, soft palate, and striated muscles of the esophagus

Question 7

Which pouch do tonsil stones form?

Answer 7

pouch 2

Question 8

Which pouch forms the tubotympanic recess?

Answer 8

pouch 1

Question 9

Which pouch forms the thymus and INFERIOR parathyroids?

Answer 9

pouch 3

Question 10

Which pouch forms the SUPERIOR parathyroids?

Answer 10

pouch 4

Question 11

A lump/growth is spotted in the back of a patients throat and appears to sit just behind/superior to the tongue. What could this be?

Answer 11

undescended lingual thyroid gland

Question 12

In an infant, what pouch descends to form the thymus and inferior parathyroids?

Answer 12

pouch 3

Question 13

What pouch is responsible for the development of the calcitonin producing cells of the thyroid?

Answer 13

pouch 4

Question 14

What pouch 4 derivative does not develop in DiGeorge syndrome?

Answer 14

C cells of thyroid (parafollicular cells)

Question 15

What pharyngeal arch component does the auditory meatus come from?

Answer 15

1st groove

Question 16

What arch ultimately forms the side of the neck?

Answer 16

arch 2

Question 17

A swollen, cyst-like area is found on a teenager just anterior to the SCM muscle. What could this be and why did it form?

Answer 17

a pharyngeal cyst due to the cervical sinus failing to obliterate

Question 18

A pharyngeal fistula is found on a patient. This means there is an abnormal tract passing between the external and internal carotid arteries. What failed to close?

Answer 18

the 2nd groove and 2nd pouch

Question 19

A child presents with an underdeveloped zygomatic bone, ear deformities, macrostomia, and micrognathia. What is the disorder and what causes it?

Answer 19

Treacher Collin syndrome due to the failure of neural crest cells to reach the first arch

Question 20

An infant presents with mandibular hypoplasia, glossoptosis, and cleft palate. What disease is this likely caused by?

Answer 20

Pierre Robin syndrome

Question 21

DiGeorge disease causes what to be absent or underdeveloped at birth?

Answer 21

thymus

Question 22

What is the mnemonic to remember DiGeorge?

Answer 22

CATCH 22 (22q11.2 deletion)
Cardiac anomalies
Abnormal facies
Thymic hypoplasia
Cleft palate
Hypocalcemia (parathyroid issues)