embryology

Question 1

where do pharyngeal (or branchial) arches develop?

Answer 1

in all vertebrates

Question 2

what order do the pharyngeal (or brachial) arches develop?

Answer 2

from head to neck

begin to develop between week 4 and 5
Arch 1- day 22
arch 2+ 3- day 24
Arch 4+ 6- day 29

Question 3

when do the pharyngeal (or brachial) arhes develop?

Answer 3

begin to develop between week 4 and 5

Arch 1- day 22
arch 2+ 3- day 24
Arch 4+ 6- day 29

Question 4

what are the three components of the pharyngeal apparatus?

Answer 4

• core pharyngeal arch (mesenchymal tissue)
• external pharyngeal cleft (ectoderm)
• internal pharyngeal pouch (endoderm)

Question 5

what separates the pharyngeal arches?

Answer 5

clefts and pouches

Question 6

what do each pharyngeal arch consist of?

Answer 6

• core of mesenchyme derived from paraxial and lateral plate mesoderm
• neural crest cells
• cranial nerve compartment
• artery (aortic arch arteries)

Question 7

what does the musculature in ENT derive from?

Answer 7

-core of mesenchyme derived from paraxial and lateral plate mesoderm

Question 8

what does smooth muscle and connective tissue in ENT derive from?

Answer 8

neural crest cells

Question 9

what processes are part of the 1st arch?

Answer 9

• maxillary process

- mandibular process

Question 10

what does the maxillary process (cranial portion) or the 1st arch go on to form?

Answer 10

• maxilla

- zygomatic

Question 11

what does the mandibular process (caudal portion) or the 1st arch go on to form?

Answer 11

• Meckel’s cartilage
• incus and malleus (ear ossicles)
• mandible
• squamous portion of temporal bone

Question 12

what is the cartilage within the 2nd cartilage called?

Answer 12

Reichert’s cartilage

Question 13

what does the 2nd arch go on to form?

Answer 13

• stapes
• styloid process of temporal bone
• stylohyoid ligament
• lesser horn of hyoid
• upper part of hyoid

Question 14

what does the 3rd arch go on to form?

Answer 14

• greater horn of hyoid bone

- lower part of hyoid bone

Question 15

what do the 4th and 6th arches go on to form?

Answer 15

-laryngeal cartilages

Question 16

what nerve supplies any structure made from the 1st arch?

Answer 16

Trigeminal nerve CN V

Question 17

what nerve supplies any structure made from the 2nd arch?

Answer 17

Facial nerve (CNVII)

Question 18

what nerve supplies any structure made from the 3rd arch?

Answer 18

Glossopharyngeal nerve (CNIX)

Question 19

what nerve supplies any structure made from the 4th and 6th arch?

Answer 19

Vagus nerve (CN X)

Question 20

where do all the muscles by CNV (trigeminal nerve) come from?

Answer 20

1st arch

Question 21

which is the only motor component of trigeminal nerve?

Answer 21

V3 mandibular nerve

Question 22

where do all the muscles supplied by CNVII (facial nerve) come from?

Answer 22

2nd arch

Question 23

what are the muscles supplied by Trigeminal nerve CNV3?

Answer 23

• muscles of mastications
• tensor veli palatini
• tensor tympani
• mylohyoid
• anterior belly of digastric

Question 24

what muscles are supplied by facial nerve CNVII?

Answer 24

• muscles of facial expression
• posterior belly of digastric
• stylohyoid
• stapedius
• auricular muscles

Question 25

where do all muscles supplied by CNIX (glossopharyngeal nerve) come from?

Answer 25

3rd arch

Question 26

what are the muscles supplied by CNIX (glossopharyngeal)?

Answer 26

stylopharyngeus

Question 27

where are muscles supplied by CNX derived from? (vagus nerve)

Answer 27

4th and 6th arches 4th: - levator veli palatini - salpingopharyngeus - palatoglossus - palatopharyngeus - 3 pharyngeal constrictors - cricothyroid 6th -intrinsic muscles of the larynx