1 - Zill - Branchial Arches

Question 1

Origin of Pharynx

Location

Sensation

Answer 1

Endoderm

Region behind Oral and Nasal Cavities

Vague sensation

Question 2

Origin of Nasal and Oral Cavities

Sensation

Answer 2

Derived from Ectoderm

Precise sensation

Question 3

Structures Found in Branchial Arches (4)

Answer 3

Cartilages

Nerve

Muscles

Arteries

Question 4

Arches, Grooves, Pouches, Membranes

Answer 4

Arches - Lumps

Grooves (Clefts) - Ectodermal clefts between adjacent arches

Pouches - Endodermal out pocketing from rostral foregun between adjacent arches

Membranes - Site of contact of Groove (ectoderm) and Pouch (endoderm)

Question 5

Branchial Arch

External / Internal Lining

Core

Answer 5

External - Ectoderm

Internal - Endoderm

Core - Mesenchym

Question 6

First Arch

Answer 6

Face, Maxillary, Mandibular Process

Surround stomodeum (primitive mouth)

Question 7

Stomodeum

Formed by?

Forms?

Contacts ____ at _____.

Beyond that is ____, formed by _____.

Answer 7

Formed by Ectoderm

Forms oral and nasal cavity

Contacts Endoderm at Oropharyngeal Membrane

Beyond that is pharynx, formed by Endoderm

Question 8

Boundary between oral/nasal cavity and pharynx?

Answer 8

Oropharyngeal Membrane

Question 9

Palatoglossal Arch

Answer 9

Site of oropharyngeal membrane, boundary of oral cavity and pharynx

Question 10

Arch / Nerve: First ( V )

Skeletal

Ligament

Muscle

“Mandibular Arch”

Answer 10

Skeletal: Malleus, Incus

Ligaments: Ant. Ligament of Malleus, Sphenomandibular Ligament

Muscles: Muscles of Mastication, Tensor Tympani, Tensor Palati, Mylohyoid, Ant. Belly of Digastric

Question 11

Arch / Nerve: Second ( VII )

Skeletal

Ligament

Muscle

“Hyoid Arch”

Answer 11

Skeletal: Stapes, Styloid Process, Hyoid Bone - lesser horn, upper hald of body

Ligament: Stylohyoid Ligament

Muscle: Muscles of Facial Expression, Stapedius, Stylohyoid, Post. Belly of Digastric

Question 12

Arch / Nerve: Third ( IX )

Skeletal

Ligament

Muscle

Answer 12

Skeletal: Hyoid Bone - greater horn, lower half of body

Ligament: N/A

Muscle: Stylopharyngeus

Question 13

Arch / Nerve: Fourth ( X )

Skeletal

Ligament

Muscle

Answer 13

Skeletal: Cartilages of Larynx

Ligaments: N/A

Muscles: All Larynx, All Pharynx (except Stylopharyngeus), All Soft Palate (except Tensor Palati)

Question 14

Arch / Nerve: Sixth ( XI )

Skeletal

Ligament

Muscle

Answer 14

Skeletal: N/A

Ligament: N/A

Muscles: Sternocleidomastoid, Trapezius

Question 15

Origin of External Auditory Meatus

Answer 15

First Branchial Groove (Cleft)

Question 16

Origin of Tympanic Membrane

Answer 16

First Branchial Membrane

Question 17

Which arch does NOT form structures in humans?

Answer 17

5

Question 18

Branchial Arch Nerves:

First

Second

Third

Fourth

Sixth

Answer 18

First - Trigeminal - V

Second - Facial - VII

Third - Glossopharyngeal - IX

Fourth - Vagus - X

Caudal Sixth - Accessory - XI

Question 19

Branchial Pouch: First

Forms

Clinical

Answer 19

Forms: Auditory Tube, Tympanic Cavity

Clinical: First Branchial Cleft (Groove) Cyst - Tract linked to external auditory meatus

Question 20

Branchial Pouch: Second

Forms

Clinical

Answer 20

Forms: Lining (crypts) of Palatine Tonsils

Clinical: Second Branchial “Cleft” (groove) cyst - Tract linked to tonsillar fossa (palatine tonsils)

Question 21

Branchial Pouch: Third

Forms

Clinical

Unique?

Answer 21

Forms: Inferior Parathyroid Gland, Thymus

Clinical: Third Branchial “Cleft” (groove) Cyst - tract at throhyoid membran or piriform recess

Migrate caudal to pouch 4

Question 22

Branchial Pouch: Fourth

Forms

Clinical

Answer 22

Forms: Superior Parathyroid Gland, C-cells of Thyroid

Clinical: N/A

Question 23

Branchial Pouch: Sixth

Forms

Clinical

Answer 23

Forms: N/A

Clinical: N/A

Question 24

Location of cysts and fistuli in lateral neck?

Answer 24

Anterior to Sternocleidomastoid Muscle

Question 25

Origin of Outpocketings of Pharynx

Answer 25

Endoderm

Question 26

Meeting of First Groove (what is structure?) and First Pouch (what is structure?)

Answer 26

Meeting - Tympanic Membrane (First Membrane) Structures = Ext. Aud. Meatus (1st Groove), Auditory Tube & Tympanic Cavity (1st Pouch)

Question 27

Cervical Sinus

Answer 27

Type of branchial groove that develops in longer depression, **normally obliterated, but can persist**

Question 28

Branchial Sinus Branchial Fistula

Answer 28

Blind pouch from **Pharynx** **- - -** **Chanel,** connecting **Pharynx** and skin of **neck**, usually passes **Anterior to Sternocleidomastoid** between Int. and Ext. Carotid A.

Question 29

Development of Thyroid

Answer 29

1. Thryoid starts as Median **Endodermal** thickening on floor of **pharynx (Tongue)** 2. Elongates to form thyroid diverticulum, descens ant. to hyoid bone and larynx 3. Throglossal duct connects diverticulum to Foramen cecum

Question 30

Lingual Thyroid

Answer 30

Thyroid gland in tongue

Question 31

Thyroglossal Duct Remnants

Answer 31

Can form throid tissue (cysts) along path of migration (midline, ant. to hyoid, larynx)

Question 32

Pyramidal Lobe

Answer 32

50% of people, attached to hyoid by fibrous strand, no clinical problems