GA2 Exam 3

Most distinctive feature in development of head and neck is what?

Pharyngeal arches

What is the old term for the pharyngeal arches?

branchial arches (resemble gills [branchial] of fish)

What do the arches initially consists of? What are they separated by on the outside?

Mesenchymal tissue; deep clefts known as pharyngeal clefts

A number of outpockets called what appear along the lateral walls of pharynx at the same time the arches and clefts develop?

pharyngeal pouches

When do pharyngeal pouches appear?

Simultaneously with development of arches of clefts

pharyngeal pouches appear where?

inside

Each pharyngeal arch consists of a core of what?

mesenchymal tissue

The core of mesenchymal tissue in the pharyngeal arch is covered by what on the outside? By what on the inside?

Surface ectoderm on outside; epithelium of endodermal origin on inside

The core of each pharyngeal arch recieves what that contribute to skeletal components of face?

Neural crest cells

Does the original mesoderm of the arches give rise to the musculature of the face and neck?

true

Each pharyngeal arch is characterized by what?

Its own muscular, nerve, and arterial components

The center of the face is formed by what?

Stomodeum

Stomodeum is also what?

future mouth

How many mesenchymal prominences arise by 4.5 weeks?

5

What mesenchymal prominences appeared by 4.5 weeks?

Mandibular, maxillary and frontonasal

What gives rise to musculature of the face and neck?

mesoderm of arches

First pharyngeal arch gives rise to what prominences?

maxillary and mandibular

First pharyngeal arch gives rise to what muscles?

mastication muscles, mylohyoid, ant. belly digastric

First pharyngeal arch gives rise to what nerve?

mandibular division of trigeminal nerve

V3

Second pharyngeal arch gives rise to what muscles?

Facial expression muscles, post. belly digastric, stylohyoid, stapedius

Second pharyngeal arch gives rise to what nerve?

Facial n

Third pharyngeal arch gives rise to what muscle?

Stylopharyngeus m.

Third pharyngeal arch gives rise to what nerve?

glossopharyngeal n.

Third pharyngeal arch gives rise to what cartilage?

Epiglottis - derived from fourth and third

Fourth and Sixth pharyngeal arch gives rise to what cartilage?

cartilage of larynx EXCEPT epiglottis

Fourth and Sixth pharyngeal arch gives rise to what muscles?

pharyngeal and laryngeal m.

Fourth and Sixth pharyngeal arch gives rise to what nerve?

vagus

What arises from fifth arch?

Nothing arises; it is rudimentary

First pharyngeal pouch (inside) forms what?

Stalk like diverticulum called tubotympanic recess

Distal part of diverticulum widens into saclike structure called what?

Primitive tympanic or middle ear cavity

Proximal part of diverticulum remains narrow forming?

auditory (Eustachian) tube

The lining of the tympanic cavity helps in formation of what?

Tympanic membrane/eardrum

Seconf pharyngeal pouch proliferates and forms what? Remaining pouch is found in ADULTS as what?

Palatine tonsils; tonsillar fossa

Dorsal region of third pharyngeal pouch differentiates into what? Ventral region forms what?

inferior parathyroid gland; thymus

Third and fourth pouch are characterized by what feature?

dorsal and ventral wings

Dorsal region of fourth pharyngeal pouch forms what?

Superior parathyroid gland

Ventral region of fourth pouch gives rise to what?

Ultimaobranchial body

Ultimaobranchial body is later Incorporated into what?

Thyroid gland

Cells of the Ultimaobranchial body give rise to what?

Parafollicular cells/c cells

What do parafollicular cells secrete? What is the hormone that it secretes involved in?

Calcitonin; involved in regulation of calcium level

Thyroid produces what hormones?

Thyroxin and calcitonin

What is a 5 week embyro characterized by? How many of them?

Pharyngeal clefts; 4 of them

Previously what was the thought of the first cleft?

Contributed the EAM of the external ear

EAM actually forms by what?

Surface ectoderm invagination to form first pharyngeal arch

What causes the first pharyngeal cleft to dissapear?

Overgrowth of the second arch as it forms external ear

Active proliferation causes what?

overgrowth of the second arch as it forms external ear

Active proliferation of the second arch further leads to what?

Overlap of third and fourth arches

Which pharyngeal clefts lose contact with the outside?

2nd, 3rd, and 4th

What happens to the cervical sinus?

It dissapears with development

When does tongue form? What form does it have?

4 weeks; tuberculum impar

What does the tuberculum impar consist of? Where do they originate from?

Two lateral lingual swellings and one medial; from first pharyngeal arch

What is a second swelling of tongue called? Where does it originate from

Copula/hypobronchial eminence; 2nd, 3rd and 4th arch

What forms the epiglottis?

A third median swelling formed by posterior 4th arch

Lateral lingual swellings form which part of tongue?

anterior 2/3 of tongue/body of tongue

Sensory innervation to anterior 2/3/body of tongue?

Mandibular division of trigeminal (V3, GSA)

What seperates anterior 2/3 and posterior 1/3?

Terminal sulcus

what is located in the middle of the terminal sulcus?

foramen cecum

Posterior 1/3 root of tongue develops from what?

2nd, 3rd(mostly), and 4th pharyngeal arch

Posterior 1/3/root sensory innervation?

Glossophrayngeal

Most of the tongue muscles derive from where? What innervates musculature?

Myoblasts originating in occipital somites

Hypoglossal (GSE)

SPECIAL Sensory(taste) to anterior 2/3 of tongue is supplied by what?

Chorda tympani of facial n.

Fissuring of tongue and hypertrophy of lingual papilla are seen where?

In down syndrome

Another name for tongue tie?

ankyloglossia

The thyroid gland appears as what? Where?

epithelial proliferation

floor of pharynx between tuberculum impar and copula (foramen cecum)

The thyroid gland in front of where?

pharyngeal gut as bilobed diverticulum

What connects thyroid to tongue in narrow canal during migration?

thyroglossal canal

What is the final position of the thyroid gland? When?

The trachea; the seventh week

Thyroid begins to function when?

end of third month

What is the first, second and third salivary gland to appear?

Parotid

Submandibular

Sublingual

Five facial primordia are what?

single frontonasal prominence

paired maxillary prominences

paired mandibular prominence

Facial primordia form around what?

Large stomodeum

Where are nasal (olfactory) placodes located?

Both sides of frontonasal prominences

What do nasal placodes eventually become? How

Nasal pits by invaginating

Ridges created during invagination of nasal placodes form what? Surround what?

nasal prominences; nasal pit

Prominences of outer edge of nasal pits create what? What about on inner edge?

lateral nasal prominence; medial nasal prominence

What happens to cleft between medial nasal and maxillary prominences?

its lost; two prominences fuse

Upper lip is formed by what?

two medial nasal and two maxillary prominences

Lower lip and jaw are formed by what?

mandibular prominences

Which two prominences merge with each other to form cheeks and maxillae? Which one enlarges to form it?

Maxillary and lateral nasal prominences; maxillary enlarges

Nose is formed by how many facial prominences?

5

Which prominence gives rise to bridge of nose?

frontonasal

Which prominence gives rise to crest and tip of nose?

the merged medial nasal

Cleft lip/palate result in what?

Abnormal appearance, difficulty speaking and eating

Anterior relations of lobes thyroid gland

Sternohyoid, sternothyroid, superior omohyoid, anterior SCM

medial relations lobes of thyroid gland

Larynx, trachea, esophogus, cricothyroid muscle, external and recurrent laryngeal nerves

Anterior relations of isthmus of thyroid gland?

Sternohyoid, sternothyroid, anterior jugular veins, fascia, skin

Posterior relations of isthmus of thyroid gland?

2, 3, 4th trachea rings

Arterial supply of thyroid gland?

Superior thyroid artery (ECA)

Inferior thyroid artery (thyrocervical t)

thyroidea ima (inconsistent origin)

Venous supply of of thyroid gland?

superior, middle, inferior thyroid vein

Nerve supply of thyroid gland?

SP fibers - vasomotor

Horomonal regulation structures of thyroid gland?

hypothalamus and pituitary gland

What disease presents with loss of weight, high BP and above normal temp?

Hyperthyroidism

What disease presents with gain of weight, low BP and lower than normal temp?

hypothyroidism

What disease presents with tachycardia, increased respiratory rate?

Hyperthyroidism

What disease presents with bradycardia, decreased respiratory rate?

hypothyroidism

What disease presents with perspiration, nervousness, exophthalamos?

hyperthyroidism

What disease presents with lethargy, low body temperature and enlargement of thyroid gland?

Hypothyroidism

exophthalamos is seen only in what disease?

Grave’s disease

What is grave’s disease?

autoimmune disease causing body to attack thyroid; causes increase in TSI