Devo Brachial Arches I & Ii

Front 1

The Pharyngeal apparatus appears? Disappears?

Back 1

during week 4 of embryonic development and disappears by week 6.

Front 2

Each pharyngeal arch contains what?

Back 2

artery, cartilage, ligament, muscle, and nerve.

Front 3

Arches are covered by ______ and lined by ___________

Back 3

Arches are covered by ectoderm and lined by endoderm.

Front 4

_______ separate arches externally and_________separate arches internally.

Back 4

Grooves separate arches externally and pouches separate arches internally.

Front 5

If groove and pouch meet, what is formed?

Back 5

pharyngeal membrane is formed by ectoderm and endoderm between arches.

Front 6

What cells migrate to form series of archs? what direction do they migrate? what are these structures separated by?

Back 6

neural crest cells migrate laterally and ventrally into future neck region, becoming mesectoderm or head mesenchyme and form a series of arches; separated by clefts

Front 7

Muscles of Arch 1:

Back 7

muscles of mastication, mylohyoid, tensor tympanic, ant. belly digastric

Front 8

Muscles of Arch 2:

Back 8

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

Front 9

Muscles of Arch 3 :

Back 9

stylopharyngeus

Front 10

Muscles of Arch 4&6 :

Back 10

crycothyroid, pharynx constrictors, larynx muscles, oesophagus (st. muscle)

Front 11

Nerves of Arch 1:

Back 11

CN V trigeminal
caudal 2/3 maxillary and mandibular
cranial 1/3 sensory nerve of head and neck, mastication motor

Front 12

Nerves of Arch 2 :

Back 12

CN VII facial

Front 13

Nerves of Arch 3 :

Back 13

CN IX glossopharyngeal

Front 14

Nerves of Arch 4&6:

Back 14

CN X vagus

Front 15

Nerves of Arch 4:

Back 15

-superior laryngeal

Front 16

Nerves of Arch 6:

Back 16

recurrent laryngeal

Front 17

What do the Arch pouches develop into?

Back 17

o Arch 1 :elongates to form tubotympanic recess ; tympanic cavity, mastoid antrum, eustachian tube
o Arch 2: forms tonsillar sinus ;mostly oblierated by palatine tonsil
o Arch 3 ;forms inferior parathyroid and thymus
o Arch 4 : forms superior parathyroid, parafollicular cells of Thyroid

Front 18

What do the Arch grooves develop into?

Back 18

only first pair persist as external auditory meatus

Front 19

What do the Arch Membranes develop into?

Back 19

only first pair persist as tympanic membrane

Front 20

What do the Arch Cartilages develop into?

Back 20

Arch Cartilages:
Arch 1- Meckel's cartilage
 dorsal ends form malleus and incus
 midpart forms ligaments
 ant. malleus, sphenomandibular
 ventral part forms mandible template
 horseshoe shaped
o Arch 2- Reichert's cartilage
 dorsal ends form stapes and Temporal bone styloid process
 ventral part ossifies to form hyoid bone components
 lesser cornu and superior body
o Arch 3- forms greater cornu and inferior hyoid
o Arch 4&6- form laryngeal cartilages (except epiglottis, from hypobranchial eminence)

Front 21

Explain devo of the Arch Arteries

Back 21

Arch Arteries:
o placental vein -> liver -> heart -> truncus arteriosus->truncus arteriosus -> aortic sac -> each arch artery ->arch artery -> dorsal aorta ->
oArch 1 :mainly lost, form part of maxillary artery
oArch 2 :stapedial arteries
oArch 3 :common carotid arteries ,internal carotid arteries
oArch 4 :left forms part of aortic arch ;right forms part right subclavian artery
oArch 6 :left- part of left pulmonary artery ,right- part of right pulmonary artery

Front 22

What is the general pattern of Arch structures?

Back 22

o Arch 1 :Mandibular Arch: 2 prominences:
 smaller upper- maxillary; forms maxilla, zygomatic bone and squamous part of temporal
larger lower- mandibular; forms mandible
o Arch 2 :Hyoid Arch: forms most of hyoid bone
oArch 3 and 4 : form neck structures