Pharyngeal Arches Flashcards by Jaren Thueson

List the 5 initially identical structures of a pharyngeal arch

nerve, cartilage and artery
Pharyngeal pouch
Pharyngeal cleft
mesenchymal core
Pharyngeal membrane

How well did you know this?

Not at all

Perfectly

A Pharyngeal membrane is what?

bilaminar

How well did you know this?

Not at all

Perfectly

The entire apparatus consists of what 4 things?

paired pharyngeal arches, pharyngeal pouches, pharyngeal clefts (or grooves), and pharyngeal membranes

How well did you know this?

Not at all

Perfectly

Each pharyngeal arch consists of a core of what two things?

somatic mesoderm and neural crest mesenchyme

How well did you know this?

Not at all

Perfectly

Somatic mesoderm contributes to which two things?

the arch artery (i.e. aortic arches 1-6) as well as skeletal muscle tissue in each arch

How well did you know this?

Not at all

Perfectly

Neural crest mesenchyme typically develops into what?

bone, nervous, cartilage, and/or connective tissue in each arch.

How well did you know this?

Not at all

Perfectly

The inside of the pharyngeal apparatus is lined by what?

endoderm that forms in-foldings or pouches between the arches

How well did you know this?

Not at all

Perfectly

Since there are 5 arches, how many pouches are there?

How well did you know this?

Not at all

Perfectly

The outside of the pharyngeal apparatus is covered by what?

ectoderm that forms outer pharyngeal clefts

How well did you know this?

Not at all

Perfectly

The first pharyngeal arch divides into what two things?

a maxillary process and a mandibular process

How well did you know this?

Not at all

Perfectly

The maxillary cartilage (palatopterygoquadrate) and mandibular cartilage (meckel’s), originate from what?

neural crest cells

How well did you know this?

Not at all

Perfectly

The maxillary cartilage forms what?

the incus of the middle ear and a small bone located in the orbital wall called the alisphenoid

How well did you know this?

Not at all

Perfectly

The mandibular cartilage forms what?

the malleus of the middle ear

How well did you know this?

Not at all

Perfectly

The first pharyngeal arch is associated with which aortic arch?

First

How well did you know this?

Not at all

Perfectly

The aortic arches are also know as what?

pharyngeal arch arteries

How well did you know this?

Not at all

Perfectly

The Somatic mesoderm of the first pharyngeal arch gives rise to what?

the terminal branch of the maxillary artery

How well did you know this?

Not at all

Perfectly

The somatic mesoderm of the first pharyngeal arch gives rise to what muscles?

the muscles of mastication

How well did you know this?

Not at all

Perfectly

First pharyngeal membrane develops into the:

tympanic membrane

How well did you know this?

Not at all

Perfectly

Neural crest mesenchyme from the first pharyngeal arch forms:

The Maxilla
Mandible
Zygomatic and squamous portion of the temporal bone

How well did you know this?

Not at all

Perfectly

The maxillary and mandibular processes of the first arch are innervated respectively, by the maxillary and mandibular branches of what?

trigeminal nerve #5

How well did you know this?

Not at all

Perfectly

The trigeminal nerve #5 originates from what?

neural plate/neural crest cells

How well did you know this?

Not at all

Perfectly

The second arch cartilage is called what?

Reichert’s

How well did you know this?

Not at all

Perfectly

The second arch cartilage gives rise to what 5 things?

The stapes of the middle ear 
The styloid process of the temporal bone
The fibrous styloid hyoid ligament 
The lesser horns of the hyoid bone 
The upper rim of the body of the hyoid bone

How well did you know this?

Not at all

Perfectly

The second pharyngeal arch gives rise to what artery?

stapedial artery

How well did you know this?

Not at all

Perfectly

Second pharyngeal arch somatic mesoderm give rise to

muscles of facial expression

The second arch is innervated by what?

facial nerve #7

Where does facial never #7 originate?

the neural plate/neural crest cells

During the fourth and fifth weeks, the rapidly expanding second pharyngeal arch overgrows what?

clefts 2,3 and 4

The second pharyngeal arch fuses caudally with the cardiac eminence forming a what?

lateral cervical sinus

The lateral cervical sinus occasionally persists on one or both sides in the form of what? Located where?

cervical cyst, just anterior to the sternocleidomastoid muscle.

A completely enclosed cyst may expand to form what?

palpable lump

Occasionally, cyst communicates with the skin via what?

an external cervical fistula

Occasionally, cyst communicates with the pharynx via what?

internal cervical fistula

internal cervical fistula most commonly open into what?

the palatine tonsil.

In the third pharyngeal arch, Somatic mesoderm gives rise to the what?

stylopharyngeus muscle

Aortic arch 3 contributes to which two things?

common carotid artery | The proximal segment of the internal carotid artery

The third arch is innervated by the:

glossopharyngeal nerve #9

What gives rise to the Laryngeal cartilages?

The mesoderm lying on the sides of the pharyngeal arch, and the lateral plate mesoderm of the fourth and sixth arches,

The fourth and sixth arches are innervated respectively by what?

superior laryngeal and recurrent laryngeal branches of the vagus nerve #10

Fourth arch gives rise to:

the arch of the aorta, right subclavian artery and original pulmonary arteries.

Fourth arch somatic mesoderm gives rise to:

constrictors of the pharynx, cricothyroid and the levator veli palatini muscles.

Sixth arch gives rise to what?

the ductus arterious and the definitive pulmonary artieries.

Sixth arch somatic mesoderm gives rise to:

the intrinsic muscles of the larynx.

First pharyngeal cleft develops into what?

the external auditory canal

Defects in the development of the first pharyngeal cleft can result in what two things?

preauricular (i.e. in front of the pinna of the ear) cysts and/or fistulas

Depending on its position, a first pharyngeal cleft cyst may threaten which nerve?

the facial nerve

Pharyngeal clefts 2, 3, and 4 are overgrown by expansion of which arch? What usually happens to these clefts?

The 2nd pharyngeal arch; obliterated

Where are cysts or fistulas (formed by defects in the development of the pharyngeal cleft) located?

anterior border of the sternocleidomastoid muscle

First Pharyngeal Pouch develops into what two things?

the Eustacian tube and middle ear cavity

Second Pharyngeal Pouch forms numerous infoldings that become what?

the crypts of the palatine tonsil.

The dorsal portion of pouch 3 forms?

the inferior parathyroid glands

The ventral portion of pouch 3 forms?

the thymus

The beginning of the thyroid gland (the thyroid primordium) first appears as a small, solid mass of what?

endoderm proliferating at the apex of the foramen cecum on the developing tongue

The thyroid primordium descends through the foramen cecum and through the tissues of the neck at the end of a slender:

thyroglossal duct

(T/F) Development of the thyroid gland is derived from the pharyngeal pouches

False

The Thyroid gland arises from what?

midline thyroid diverticulum that forms from the endoderm

The endoderm cells in the floor of the pharynx just caudal to the 1st pharyngeal arch differentiate into what?

the follicular cells of the thyroid gland

Neural crest cells of the ultimobranchial body migrate into the gland and give rise to what?

the parafollicular cells (C-cells) of the thyroid.

The thyroid glands parafollicular cells (also called C cells), primary function is to secrete what?

calcitonin

Anomalies in thyroid development can result in what?

ectopic thyroid tissue and/or cysts

the thyroglossal duct is what type of structure?

Midline

What are normal evidences of Creatinism or hypothroidism?

Deficient mental and physical development. Short and wide face Underdeveloped mandible Overdeveloped maxilla Large, thick and protruding tongue (Macroglossia) Delayed eruption of primary and permanent teeth Short and thickened long bones

What are normal evidences of Graves disease or hyperthyroidism?

``` Weight loss—despite increased appetite Anxiety, restlessness, tremors, irritability, difficulty sleeping (insomnia) Heat intolerance, sweating Chest pain, palpitations Shortness of breath, difficulty breathing Muscle weakness Goiter Prominent, bulging eyes ```

What are goiters?

Enlargement of the thyroid gland

What does parathyroid hormone (PTH) control?

calcium, phosphorus, and vitamin D levels in the blood and bone.

DiGeorge syndrome can cause what?

maller than normal parathyroid glands, which secrete too little parathyroid hormone (PTH), leading to hypoparathyroidism.

PTH acts on mainly which two organs?

the bone and the kidney

What is bone made of?

- Collagen - Calcium - Bone cells (Osteoclasts, Osteoblasts, Osteocytes )

PTH stimulates the 1-α hydroxylase activity in the kidney, resulting in an increase in what?

1,25 dihydroxyvitamin D production

PTH also increases the reabsorption of what? But has the opposite effect on?

Calcium, Phosphorous

What is hyperparathyroidism?

high PTH

Calcium has a (positive/negative) feedback effect on the parathyroid glands

Negative

phosphorus has been shown to have what type of effect on the parathyroid glands?

a direct stimulatory

DiGeorge syndrome often causes defects in which organ?

Heart

What four abnormal structures are included in the tetralogy of Fallot

Pulmonary stenosis Right ventricular hypertrophy Overriding aorta Ventricular septal defect (VSD)

DiGeorge syndrome causes dysfunction in which gland?

Thymus gland

(T/F) Cleft palate and or cleft lip is a common condition of DiGeorge syndrome

True

What are some particular facial features that may be present in people with DiGeorge syndrome?

``` Small low-set ears Wide-set eyes Hooded eyes Long face Small mandible Bowing up of the upper lip ```

What are two other problems DiGeorge syndrome can contribute to?

Learning, behavioral and mental health problems. | Autoimmune disorders.