Embryology Oucod Test 2

Front 1

Which of the 6 branchial arches is rudimentary

Back 1

5th

Front 2

What 2 prominences does the 1st branchial arch split into

Back 2

maxillary prominence and mandibular prominence

Front 3

how many total branchial grooves are there between the arches

Back 3

4

Front 4

What is the name of the structure that is ectodermally lined and separated from the foregut by the oropharyngeal membrane

Back 4

Stomodeum - also makes up ant 2/3 of oral cavity

Front 5

What are the four internal evaginations of endoderm that separate each branchial arch called

Back 5

Pharyngeal pouches

Front 6

What is the meeting of ectoderm of branchial groove with endoderm of a pharyngeal pouch called.

Back 6

Branchial Membrane

Front 7

What are the three structural components of a typical branchiall arch

Back 7

ectodermal outer covering(epidermis)
endodermal inner lining(mucosal)
mesenchyme core - branchiomeric mesenchyme

Front 8

what four things form from the mesenchymal core of a branchial arch

Back 8

blood vessel - endothelium of aortic arch
cartilaginous bar - forms from neural crest cells
muscular components - from cephalic paraxial mesoderm(somitomeres)
cranial nerve

Front 9

The external acoustic canal forms from what branchial groove

Back 9

1st - it forms from the ectodermal epithelium of the groove

Front 10

What happens to branchial grooves 2-4 as the 1st grow down

Back 10

they regress and form cervical sinus

Front 11

What does the thyroid descend from

Back 11

Thru foramen cecum

Front 12

What is the name of the cartillage in the mandibular prominence that forms the mandible and malleus and incus

Back 12

Meckels cartilage

dorsal part forms malleus and incus from endochondral ossification

ventral portion regresses to direct intramembranous formation of mandible

Front 13

What things does the maxillary prominence form

Back 13

maxilla, zygomatic bone and squamous portion of temporal bone by intramembranous bone formation

Front 14

What is the name of the cartilage found in branchial arch 2

Back 14

Reichert's cartilage

Front 15

What does Reichert's cartilage form

Back 15

stapes, styloid process, upper 1/2 of hyoid bone by endochondral ossificaiton

Front 16

What bone does branchial arch 3 form

Back 16

lower half of hyoid bone by endochondral ossification

Front 17

What do branchial arches 4 and 6 form

Back 17

cartilages of larynx except the epiglottis which comes from the tongue development

examples
cricoid, thyroid

Front 18

What nerve innervates the 1st, 2nd, 3rd, 4th and 6th branchial arches

Back 18

V - maxillary and mandibular branches
VII
IX
X - superior laryngeal branch
X - recurrent vagus branch

Front 19

What muscles does branchial arch 1 form

Back 19

muscles of masitcation, mylohyoid, anterior belly of the digastric, tensor tympani and tensor veli palitini

Front 20

What does the tensor tympani attach to

Back 20

the maleus it helps dampen sounds

Front 21

What muscles does the 2nd branchial arch form

Back 21

muscles of facial expression, stylohyoid, post belly of digastric and stapedius

Front 22

What muscle does branchial arch 3 form

Back 22

stylopharyngeus

Front 23

What muscles do branchial arch 4 form

Back 23

cricothyroid, levator veli palatini, constrictors of pharynx, palatoglossus

Front 24

What muscles do branchial arch 6 form

Back 24

intrinsic muscles of larynx

Front 25

What does the tubotympanic recess(derived from Pharyngeal pouch 1) give rise to

Back 25

middle ear cavity and pharyngotympanic canal(eustachian tube)

the first branchial membrane forms the tympanic membrane

Front 26

What does pharyngeal pouch 2 give rise to

Back 26

epithelium of palatine tonsil and tonsilar crypts

Front 27

What is unique about the 3rd pharyngeal pouch

Back 27

it evaginates to form a dorsal and ventral portion

dorsal - inferior thyroid glands
ventral - epithelial reticulus of thymus gland

Front 28

What do the dorsal and ventral portions of pharyngeal pouch 4 form

Back 28

dorsal - superior parathyroid glands
ventral - ultimobranchial body which is associated with neural crest cells that form c-cells("parafoliculate") of thyroid gland

Front 29

What is unique about the superior and inferior parathyroid glands up until the piont that they migrate

Back 29

the inferior are superior to the superior

Front 30

How is the thyroid formed

Back 30

it is an evagination of endoderm that develops from a diverticulum just caudal to the median tongue bud

Front 31

What does the thyroid descend thru

Back 31

thyroglossal duct

Front 32

What are some congenital malformations of the thyroid that can occur

Back 32

thyroglossal duct cyst, thyroglossal duct sinus or ectopic thyroid gland

Front 33

What are some common branchial malformations

Back 33

Branchial sinus, fistula or cyst

Front 34

What is first arch syndrome

Back 34

malformations of the ear, mandible, zygoma and palate due to insufficient migration of neural crest cells into the first arch

Front 35

What is DiGeorge Syndrom

Back 35

lack of parathyroid glands or thymus glands

It can lead to facial abnormalities such as low set ears and small mouth

Also can lead to defects in outflow tract of heart and great vessels

Front 36

If a child has a midline swelling beneath the arch of the hyoid bone what could it be

Back 36

Thyroglossal duct cyst

Front 37

What can DiGeorge patients die from

Back 37

they are immune compromised and can die of heart defects due to lack of heart partitioning during development

Front 38

What does Rathke's pouch end up forming

Back 38

ant lobe of pituitary(adenohypophisis)

Front 39

What are the five facial primordia

Back 39

frontonasal prominence, maxillary prominences(paired) and mandibular prominences(paired)

Front 40

Where does the nasolacrimal groove form

Back 40

between the lateral nasal prominence and the maxillary prominence

Front 41

What does the nasolacrimal groove give rise to

Back 41

nasal lacrimal duct

Front 42

What are nasal placodes

Back 42

they are the areas that become depressed and eventually form nasal pits(nostril holes)

Front 43

What do the lateral nasal prominences form

Back 43

sides of the nose(alae)

Front 44

What does the medial nasal prominence form

Back 44

nasal septum

Front 45

How is the intermaxillary segment formed

Back 45

fusion of the paired medial nasal prominences

forms the
philtrum of lip
fleshy nasal septum
premaxillary part of maxilla-holds 4 incisors
primary palate

Front 46

What nerve innervates the frontonasal prominence, the maxillary prominence and mandibular prominence

Back 46

V1, V2 and V3 respectively

Front 47

What is the structure that separates the nasal pit from the oral cavity

Back 47

oronasal membrane - it eventually ruptures and gives continuity between oral cavity and nasal cavity

Front 48

When the nasal pit invaginates what does it form

Back 48

nasal sac which then becomes the naris

Front 49

What are the paired shelves the lift from the maxillary prominences to form the secondary palate called

Back 49

lateral palatine processes

Front 50

What parts make up the secondary palate

Back 50

lateral palatine processes fuse with nasal septum

Front 51

What is the function of the palate

Back 51

separates oral and nasal cavities except in region of pharynx

Front 52

Anterior cleft malformations occure what in relation to the incisive forament

Back 52

anterior to it

anterior cleft malformations are malformations of the primary palate

Front 53

what is the name for an anterior cleft malformation

Back 53

cleft lip - results due to a incomplete fusion of maxillary prominence with the medial nasal prominence

Front 54

What is a posterior cleft malformation called

Back 54

cleft palate - forms due to incomplete fusion of lateral palatine processes and nasal septum

Front 55

What is an oblique facial cleft

Back 55

it occurs at position of nasolacrimal duct and is due to incomplete fusion of lateral and medial nasal prominences with the maxillary prominence