Development Of Pharyngeal Arches

Question 1

What does the pharyngeal apparatus consist of?

Answer 1

J

Question 2

J

Answer 2

J

Question 3

J

Answer 3

J

Question 4

____ cells migrate from the forebrain, midbrain, and hindbrain.

Hindbrain populates the _____ and is divided into segments called _____.

Pharyngeal arch 1 streams from ____.
PA 2 streams from _____.
PA 3/4 streams from ____.
Pa 3 and 5 produce few ____.

Answer 4

NCC

Pharyngeal arches

Rhombomeres

R1-2
R4
R6-6
NCC

Question 5

Each arch consists of a core of ____ covered externally by ____ and internally by ______.

Answer 5

Mesenchyme

Ectoderm

Endoderm

Question 6

Mesenchyme is derived from ____ that migrate into arches during the _____ week.

Arches support the lateral walls of the ____.

NCC migration into the arches and differentiation into mesenchyme becomes the ______ and ______.

Answer 6

NCC; 4th

Primordial pharynx

Maxillary and mandibular prominences

Question 7

____ arch separates into the maxillary and mandibular prominences.

During ____ week the PA2 overgrown PA3/4 to form the ____.

By end of 7th week the ____ disappears.

Answer 7

1st

Cervical sinus (ectodermal depression)

Cervical sinus

Question 8

N

Answer 8

N

Question 9

J

Answer 9

J

Question 10

J

Answer 10

J

Question 11

Meckel’s cartilage is the cartilage of _____.

Answer 11

PA 1

Question 12

Riechert’s cartilage is the cartilage of ____.

Riechert’s plus the dorsal anlage form the ____ and ____.

Cartilage between the styloid and hyoid regress and the ____ forms the styloidhyoid L.

Ventral end of Riechert’s ossifies and forms the _____.

Answer 12

PA 2

Stapes and styloid process of temporal bone

Perichondrium

Lesser cornu/horn of hyoid bone

Question 13

Third arch

Answer 13

J

Question 14

4th and 6th arch cartilages

Answer 14

J

Question 15

Muscular components of the PA are derived from ____ and _____.

What muscles do PA1- PA6 form? (Not PA5)

What CN go with each arch?

Answer 15

Paraxial mesoderm and prechordal plate

PA1: muscles of mastication (CN V)

PA2: stapedius and muscles of facial expression (CN VII)

PA3: stylopharyngeus m (CN IX)

PA4: cricothryroid, levator veli palatini, and constrictors of pharynx (CN X)

PA6: intrinsic muscles of the larynx (CN X)

Question 16

Special visceral efferent supply ____ derived from the arches.

Special visceral afferent supply the ____ and ____ of the head and neck.

Answer 16

Muscles

Dermis and mucous membranes

Question 17

Trigeminal N

Answer 17

J

Question 18

Facial N

CN IX

Answer 18

J

Question 19

Vagus

Answer 19

J

Question 20

Primordial pharynx is derived form the ____. It widens cranially and joins the ____ but narrows as it joints the esophagus.

____ of the pharynx lines the internal aspects of the arches and the pharyngeal pouches.

Answer 20

Foregut; stomodeum

Endoderm

Question 21

J

Answer 21

J

Question 22

The ____ appear in the floors of the pharyngeal grooves. They form where epithelial of the grooves and pouches meet. They quickly are infiltrated and separated by ____.

The 1st pharyngeal membrane plus the intervening mesenchyme forms the _____.

Answer 22

Pharyngeal membranes

Mesenchyme

Tympanic membrane

Question 23

The _____ of the pouches forms organs in head/neck.

The 1st pharyngeal pouch expands into the ____.

Answer 23

Endoderm

Tubotympanic recess

Question 24

Y

Answer 24

Y

Question 25

The 2nd pharyngeal pouch is obliterated as the ____ develops; but part of cavity remains as the ___, a depression between the palatoglossal and palatopharyngeal arches.

Answer 25

Palatine tonsil Tonsillar sinus

Question 26

J

Answer 26

J

Question 27

The 3rd pharyngeal pouch separates into two regions? By ____ week, the dorsal bulbar part differentiates into the _____. Epithelium of elongated ventral parts proliferate and obliterate the cavities. The two parts come together forming the ____.

Answer 27

Solid, dorsal, bulbar part Hollow, elongated, ventral part Inferior parathyroid gland Thymus

Question 28

The 4th pharyngeal pouch expands into two parts? By 6th week, the epithelium of the dorsal bulbar parts differentiate into the _____ and lies on the dorsal surface of the thyroid gland.

Answer 28

Dorsal, bulbar part Elongated, ventral part Superior parathyroid gland

Question 29

____ separates the pharyngeal arches and are separated externally. They arise during the ____ weeks. The first pair become the ____. Grooves 2-4 lie in the ____; all are obliterated by ____ week as the neck develops. Birth defects of ____ groove are common.

Answer 29

Pharyngeal grooves 4-5th External acoustic meatus Cervical sinus; 7th week; 2nd groove

Question 30

Cervical (brachial) cysts are remnants of the ____ or ____. Cysts lie free in neck, inferior to the angle of the mandible.

Answer 30

Cervical sinus; 2nd groove

Question 31

The thyroid gland is the first endocrine gland to develop from ____. It forms a median endothermal thickening in the floor of the ____. It descends in the neck with tongue growth and passes ventral to developing hyoid bone and laryngeal cartilages. It connects to the tongue by a narrow tube called the ____.

Answer 31

Thyroid primordium Primordial pharynx Thyroglossal duct

Question 32

During the ____ week, a solid mass of endodermal cells is broken up into epithelial cords by vascular ____. ____ has degenerated and disappeared. Proximal opening of the duct persists as ____ on the dorsal tongue. ____ extends superiorly from the isthmus.

Answer 32

7th Mesenchyme Thyroglossal duct Foramen cecum Pyramidal lobe

Question 33

During the ____ week, the cords have divided into cellular groups and a lumen. The cells are arranged in a single layer around the ____.

Answer 33

10th Thyroid follicles

Question 34

During the ____ week, the colloid appears and synthesis of TH occurs. During ____ week the levels of TSH and thyroxine increase. During _____ fetal TSH and thyroxine reach adult levels.

Answer 34

11th 20th 35th

Question 35

Elongated ventral part of each 4th pouch develops into an _____ and fuses with the thyroid gland. Cells disseminate within the thyroid and form _____ that will produce calcitonin. These cells form from ____.

Answer 35

Ultimopharyngeal body Parafollicular cells NCC

Question 36

____ is abnormal development of the components of the 1st arch. Causes malformation of eyes, ear, mandible, and palate. This results from insufficient migration of ____ into first arch during ____.

Answer 36

First pharyngeal arch syndrome NCC; 4th week

Question 37

Treacher-Collins syndrome

Answer 37

J

Question 38

____ is associated with hypoplasia of the mandible, cleft palate, and defects of eyes and ears. Initiating defect is a small mandible called ____; results in posterior displacement of the tongue

Answer 38

Pierre robin sequence Micrognathia