Pharyngeal Derivatives And VISCERAL INNERVATION OF THE HEAD Flashcards by Lucía Costa Azqueta

Embryonic development of the thyroid gland

Endoderm of the pharyngeal arches
From the foramen cecum, the cells migrate through the thyroglossal duct.

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Anomalies of the thyroglossal duct and thyroid gland

thyroglossal cysts – located at the midline

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Relationships of the thyroid gland

Trachea
Cricoid
Infrahyoid muscles
Lateral to the esophagus
Recurrent laryngeal nerve
Internal jugular vein, common carotid and vagus (lateral)

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At which vertebral level does the cricoid finish?

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Where does the inferior thyroid artery branch from?

From the thyrocervical trunk (which comes from the subclavian artery).

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Venous drainage of the thyroid gland

Inferior, middle and superior thyroid vein

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On what system do the visceral fibers of the PS in glands act?

They control smooth muscle, they stimulate secretion

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What kind of gland is the thyroid gland?

Endocrine as it releases hormones.

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How are the sympathetic fibers (which come from the sympathetic trunk) that accompany vessels to the thyroid gland?

They are only vasomotor

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Sympathetic ganglion start at T1: TRUE OR FALSE

FALSE
We have a sympathetic ganglion (with postganglionic neurons) at each vertebral level, even though the preganglionic neurons of the sympathetic trunk come from the spinal cord from T1-L2.

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Pathway of the postganglionic fibers (sympathetic system) that innervate the face.

The postganglionic fibers that innervate the face come from the cervical ganglion (sympathetic trunk), and they accompany the arteries till the face.

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Origin of external auditory meatus

1st pharyngeal cleft

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Typical location of lateral cervical cysts

Along the medial border of the sternocleidomastoid muscle

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What are the derivatives of the pharyngeal pouches?

Enlargements of the endodermal lining of the PAs

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What does the 1st pharyngeal pouch develop into?

pharyngotympanic tube & tympanic membrane

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What does the 2nd pharyngeal pouch develop into?

Palatine tonsil

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What does the 3rd pharyngeal pouch develop into?

inf parathyroid glands, C cells and thymus

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What does the 4th pharyngeal pouch develop into?

Superior parathyroid glands

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DiGeorge Syndrome

DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a genetic condition that can affect many parts of your body and causes heart abnormalities, an impaired immune system and developmental delays.

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Name the three greater salivary glands

Parotid, submandibular and sublingual

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Name the lesser salivary glands

Palatine, buccal, labial, palatoglossal & lingual

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Relationships of the parotid gland

external carotid artery and retromandibular vein

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Parotid duct=

Stenon’s duct (se puede observar en espejo)

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Where is the opening of the submandibular duct?

Sublingual papilla

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Where is the parasympathetic innervation that innervates the glands of the head? (Preganglionic neurons)

Preganglionic PS neurons innervating the glands in the head are located in the brainstem (PS VE travel with CNs)

PS innervation of glands

1. Parotid gland – fibers that travel with the lesser petrosal nerve (IX CN) - otic ganglion- auriculotemporal nerve (V3) 2. Submand/sublingual glands– fibers that travel with the chorda tympani (VII) – lingual nerve (V3) - submandibular ganglion 3. Palatine and nasal mucosa - fibers that travel with the greater petrosal (VII) - nerve of the pterygoid canal -pterygopalatine ganglion 4. Lacrimal gland – fibers that travel with the greater petrosal (VII) - n pterygoid canal- pterygoplatine ganglion - zygomatic (V2) – communicating branch - lacrimal (V1) to reach the gland

Where is the sympathetic innervation of the glands?

Sympathetic innervation of glands accompany the arteries to the glands

Innervation of constrictor m of the pupil and ciliary muscles

PS fibers with III CN - ciliary ganglion – short ciliary nerves

Innervation of dilator pupillae muscles

Sympathetic fibers with the ophthalmic artery – short & long ciliary nerves

What can happen if the thyroglossal duct does not fully obliterate?

It can lead to cysts at any point of the migratory pathway.

The thyroid gland is covered by … (3) muscles.

Sternothyroid, sternohyoid, omohyoid

When having a thyroid surgery, we have to be careful with the … nerve

Recurrent laryngeal: it passes between the esophagus and the trachea and the thyroid

BLOOD SUPPLY THYROID GLAND - …: a branch of the thyrocervical trunk -…: a branch of the external carotid artery

- inferior thyroid artery - superior thyroid artery

VENOUS DRAINAGE THYROID GLAND - Superior thyroid vein coming from… - Middle thyroid vein coming from… - Inferior thyroid vein coming from…

- Internal jugular vein - Internal jugular vein - Brachiocephalic vein

What kind of innervation do we find in the thyroid gland?

Sympathetic innervation: from middle and inferior cervical ganglia, they accompany the arteries and produce vasoconstriction (SYMPATHETIC TRUNK)

1st pharyngeal cleft gives rise to…

External auditory meatus

2nd, 3rd and 4th pharyngeal clefts give rise to…

Cervical sinus which disappears

If cervical sinus does not diasappear, … are formed

Lateral cervical cysts

The endoderm of the arches proliferates and forms…

Pharyngeal pouches

1st pharyngeal pouch gives rise to…

pharyngotympanic tube & tympanic membrane

2nd pharyngeal pouch gives rise to…

Palatine tonsil

3rd pharyngeal pouch gives rise to…

inf parathyroid glands, C cells and thymus

4th pharyngeal pouch gives rise to…

Superior parathyroid glands

Name the greater salivary glands:

Parotid, submandibular, sublingual

Name the lesser salivary glands:

palatine, buccal, labial, palatoglossal & lingual

Parotid gland is a … gland

Serous

Submandibular gland is predominantly…

Serous

Sublingual gland is predominantly …

Mucous

The parotid gland encloses….

The retromandibular vein and the external carotid

The … penetrates the parotid gland

Facial nerve

The … of the parotid gland courses along the masseter, pierces the buccinator and enters the oral cavity.

Stenon duct

PS innervation of the parotid gland

lesser petrosal nerve (IX CN) - otic ganglion- incorporate into the auriculotemporal nerve (V3)

Submandibular gland ducts open into …

Sublingual papillae

Preganglionic PS neurons innervating the glands in the head are located in the …

Brainstem

What is the parasympathetic innervation to sublingual and submandibular glands?

chorda tympani (VII CN) – incorporates/accompanies the lingual nerve (V3) - submandibular ganglion

PS innervation (secretomotor) of the mucosa of nasal cavities, paranasal sinuses, palate:

greater petrosal (PS) - nerve of the pterygoid canal -pterygopalatine ganglion From the ganglion, PS and S fibers accompany the corresponding sensory nerves and arteries

PS innervation of the lacrimal gland

greater petrosal (VII) – n pterygoid canal- pterygoplatine ganglion - zygomatic (V2) – communicating branch - lacrimal (V1) to reach the gland

Sympathetic innervation of glands accompany the … to the glands

arteries

PS INNERVATION EYE MUSCLES

PS fibers with III CN - ciliary ganglion – short ciliary nerves (to produce constriction/miosis and change the curvature of the lens by contracting ciliary muscles).

Sympathetic innervation of the eye

Sympathetic fibers with the ophthalmic artery – short & long ciliary nerves to innervate dilator pupillae m.

Why the curvature of the lens does not need to be controlled by the sympathetic system?

Because when the pupil is dilated, enough light comes in to create a sharp image. There is no need to adjust lens curvature.

What is the embryonic origin of the structures identified as number 1?

4th pharyngeal pouch

Which of the following structures does NOT pass through the parotid gland? retromandibular vein internal carotid artery external carotid artery branches or trunks of the facial nerve

Internal carotid artery

The thyroid gland is located at approximately the level of C5 to T1 vertebrae (T/F)

True

An individual has a large blood clot at the right thyrocervical trunk. Which of the following arteries supplying the thyroid gland is most likely to be affected? inferior thyroid artery external carotid artery superior thyroid artery common carotid artery

Inferior thyroid artery

Mark the INCORRECT association between the ganglion containing parasympathetic motor neurons and the gland innervated by them submandibular ganglion - submandibular gland pterygopalatine ganglion - sublingual gland ciliary ganglion - constrictor muscle of the pupil pterygopalatine ganglion - lacrimal gland otic ganglion - parotid gland

Pterygopalatine ganglion-sublingual gland

The thyroid gland originates from ...

The floor of the pharynx

Identify the structures pointed at in the image:

1. Mylohyoid 2. Lingual nerve 3. Submandibular gland 4. Submandibular duct

The parotid gland is located in the retromandibular fossa, anterior to the sternocleidomastoid muscle, superficial to the masseter and inferior to the zygomatic arch (T/F)

True

Mark the INCORRECT association between cranial nerve and parasympathetic fibers travelling with it chorda tympani - V nerve lesser petrosal nerve - IX nerve greater petrosal nerve - VII nerve PS fibers to the pupil - III nerve

CHORDA tympani- V nerve

An individual is set to undergo a thyroidectomy. Which of the following anatomical relationships is correct? The thyroid gland is positioned superficial to the sternothyroid and sternohyoid muscles The superior and inferior thyroid arteries run between the pretracheal layer of the deep cervical fascia and the fibrous capsule of the thyroid gland The left and right thyroid lobes are connected by the pyramidal lobe The thyroid gland typically sits at the level of C3 to C6

The superior and inferior thyroid arteries run between the pretracheal layer of the deep cervical fascia and the fibrous capsule of the thyroid gland

…. muscle helps in the closure of the mandible

Medial pterygoid muscle

…. muscle helps in the lateral movement of the mandible

Lateral pterygoid

Name all muscles innervated by the motor branch of the Trigeminal nerve.

The … muscle takes insertion both in the articular capsule and the intraarticular disc

Lateral pterygoid

Name the 4 masticator muscles

Masseter, temporal muscle, medial and lateral pterygoid muscle

Name the two muscles in the floor of the oral cavity which contribute to mastication and their function

Mylohyoid muscle and anterior belly of the digastric muscle. They depress the mandible

The anterior belly of the digastric is innervated by the…, however the posterior belly of the digastric by the…

Motor branch of the Trigeminal, facial nerve.

Name a muscle related to mastication which tenses the soft palate

Tensor veli palatini

Name these muscles related to mastication

Protrusion is mainly carried out by…

LATERAL PTERYGOID MUSCLE

Retraction is mainly carried out by…

TEMPORALIS AND DEEP PART OF MASSETER

Elevation is carried out by…

Temporalis, masseter and medial pterygoid

Depression is carried out by…

Muscles in the floor of the mouth (anterior belly of the digastric and mylohyoid) + gravity

The … trunk of V3 is the one which is largely motor

Name the branches of the anterior trunk of the mandibular nerve

Deep temporal nerves, nerve to lateral pterygoid, masseteric nerve, nerve to medial pterygoid, branch to tensor veli palatini, branch for tensor tympani.

Motor component of the posterior trunk of the mandibular nerve and what it innervates

Nerve to mylohyoid: it innervates the my,hyoid muscle and the anterior belly of the digastric

The … nerve travels along with the inferior alveolar nerve

Mylohyoid (from the posterior trunk of the mandibular nerve)

Name the nerve

Masseter nerve

The only sensory branch of the anterior trunk of V3 is the … which supplies the mucosa of the oral cavity

buccal nerve

The posterior trunk of V3 is mostly …

Sensory

Name the sensory nerves of the posterior trunk of V3

- Auriculotemporal nerve - Inferior alveolar nerve: divides into incisive and mental nerve when exiting through the mental foramen - Lingual nerve (CHORDA tympani attaches to it)