Development of the Head and Neck

Question 1

Occipital sclerotomes form the upper half of the ____ and the rest fuse to form the occipital bone

Answer 1

atlas

Question 2

occipital myotomes will form the muscles of the ____

Answer 2

tongue

Question 3

The nerves of the occipital somites fuse, become entrapped in the occipital bone and innervate the muscles of the tongue as the ____ nerve

Answer 3

hypoglossal

Question 4

Sclerotomes in the cervical region form cervical vertebrae and the bottom half of the atlas. Myotomes in this region form the muscles of the neck. True or false?

Answer 4

true

Question 5

The nerves of the cervical somites innervate the neck muscles via _____ ____ nerves

Answer 5

cervical spinal

Question 6

Most typical features in development of head and neck are formed by _____ arches.

Answer 6

pharyngeal

Question 7

The following description is of what pharyngeal arch:
muscle: muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani, tensor palatini

bone: premaxilla, maxilla, zygomatic bone, part of temporal bone, mandible, malleus, incus
ligament: anterior ligament of malleus, sphenomandibular
nerve: V2 and V3 of trigeminal

Answer 7

1st (Mandibular) arch

Question 8

The following description is of what pharyngeal arch:
muscles: muscles of facial expression, sylohyoid, posterior belly of digastric, stapedius

bone: stapes, stylohyoid process of temporal bone, lesser horn of hyoid, upper part of body of hyoid

ligament: stylohyoid
nerve: facial

Answer 8

2nd (hyoid) arch

Question 9

The following description is of what pharyngeal arch:

muscle: stylopharyngeus
bone: greater horn of hyoid, lower part of body of hyoid
nerve: glossopharyngeal

Answer 9

3rd arch

Question 10

What muscles do the 4th and 6th pharyngeal arches form?

Answer 10

4th: cricothryoid, levator palatine, constrictors of pharynx
6th: intrinsic muscles of larynx

Question 11

What nerve do the 4th and 6th pharyngeal arches form?

Answer 11

vagus

4th: superior laryngeal branch
6th: recurrent laryngeal branch

Question 12

The ____ ____ lining of the pharyngeal pouches gives rise to a number of important organs

Answer 12

epithelial endodermal

Question 13

The first pharyngeal pouch, forms a diverticulum which comes in contact with epithelial lining of the first pharyngeal cleft, the ____ _____ meatus

Answer 13

external auditory

note: expands to form middle ear tympanic cavity and auditory tube

Question 14

The second pharyngeal pouch forms what?

Answer 14

palatine tonsils

Question 15

The dorsal wing of the third pharyngeal pouch differentiates into the ____ ____ gland. The ventral wing differentiates into the ____.

Answer 15

inferior parathyroid; thymus

Question 16

The dorsal wing of the fourth pharyngeal pouch becomes the ____ ____ gland. The ventral wing gives rise to the ______ body.

Answer 16

superior parathyroid; ultimobranchial

Question 17

What is the function of the ultimobranchial body?

Answer 17

is incorporated into the thyroid gland and secretes calcitonin

Question 18

This syndrome occurs because the third and fourth pharyngeal pouches fail to differentiate into thymus and parathyroid glands. In most cases there is a micro deletion in the q11.2 region of the chromosome 22 and neural crest defects.

Answer 18

DiGeorge syndrome

Question 19

What are the clinical signs of DiGeorge syndrome?

Answer 19

infants born without thymus and parathyroid gland and have defects in their cardiac outflow tracts; anomalies of mouth (small mouth and chin), prominent nose with rounded tip, unusually shaped ears

Question 20

There is a period of overlapping growth between pharyngeal arches 2,3,4 and pharyngeal clefts 2,3,4. During this time, what is formed? it usually disappears with further growth

Answer 20

cervical sinus

Question 21

The skeletal structures of the face are formed by mesenchyme that is derived from ____ ___. The other elements in the head, such as the parietal, occipital, temporal bones, and voluntary muscles are formed by mesenchyme that is derived from ____ ____.

Answer 21

neural crest; paraxial mesoderm

Question 22

Mesenchyme derived from the lateral plate mesoderm will form what?

Answer 22

cartilages of the larynx

Question 23

During the fourth week, the center of the face is formed by the _____, surrounded by first pair of pharyngeal arches.

Answer 23

stomodeum

Question 24

On both sides of frontonasal prominence, thickenings of surface ectoderm, the nasal _____ originate under the influence of the ventral portion of forebrain

Answer 24

placodes

Question 25

During the fifth week, the nasal placodes invaginate, forming nasal pits, which are surrounded by ridges of tissue that form what?

Answer 25

lateral and medial nasal prominences

Question 26

The _____ lip is formed by two medial nasal prominences and the two maxillary prominences

Answer 26

upper

Question 27

The maxillary prominences are separated from the lateral nasal prominences by the _______ groove

Answer 27

nasolacrimal

Question 28

Describe how the tongue appears and forms in week 4

Answer 28

appears in the form of two lateral lingual swellings and one medial lingual swelling (from first pharyngeal arch)

Question 29

A second medial swelling of the tongue, the _____, is formed by mesoderm of the 2nd, 3rd, and 4th arch.

Answer 29

copula

Question 30

The third median swelling, formed by the posterior part of the 4th arch marks development of the ____

Answer 30

epiglottis note: immediately behind this is the laryngeal orifice, flanked by arytenoid swellings

Question 31

Since the mucosa covering the body of the tongue originates form the first pharyngeal arch, sensory innervation is done by what nerve?

Answer 31

mandibular branch of trigeminal

Question 32

Tongue musculature is derived from myoblasts originating in occipital somites, thus tongue musculature is innervated by which nerve?

Answer 32

hypoglossal

Question 33

What is ankylogossia?

Answer 33

tongue-tie - frenulum extends to tip of tongue, anchoring it down

Question 34

The thyroid gland appears as an epithelial proliferation in the floor of the pharynx between the tubercular impar and the copula at a point later indicated by the _____ _____

Answer 34

foramen cecum

Question 35

The thyroid gland reaches its final position at week _____ and begins to function at the end of the ____ month

Answer 35

7; 3rd

Question 36

The fusion of the primary and secondary palate is marked by what foramen?

Answer 36

incisive

Question 37

During the ____ week, the nasal pits deepen considerably. At first, the oronasal membrane separates the nasal pits from the primitive oral cavity by way of the newly formed foramina, the ____ ____

Answer 37

6; primitive choanae note: the definitive choanae lie at the junction of the nasal cavity and the pharynx

Question 38

Paranasal air sinuses develop their maximum size during ____

Answer 38

puberty

Question 39

Lateral cleft lip happens more in males and is partial or complete lack of fusion of ____ prominences with the ____ ____ prominences on one or both sides

Answer 39

maxillary; medial nasal

Question 40

Cleft palate is the lack of fusion between what?

Answer 40

primary and secondary palates

Question 41

Median cleft lip is due to incomplete fusion of the two ____ ____ prominences, usually accompanied by a deep groove between the two halves of the nose.

Answer 41

medial nasal

Question 42

This occurs more freq in females, due to incomplete fusion of the palatine shelves

Answer 42

cleft palate

Question 43

What causes oblique facial clefts?

Answer 43

failure of the maxillary prominence to fuse with the lateral nasal prominence - leaves nasolacrimal duct exposed