Pharyngeal Derivatives And VISCERAL INNERVATION OF THE HEAD Flashcards
Embryonic development of the thyroid gland
Endoderm of the pharyngeal arches
From the foramen cecum, the cells migrate through the thyroglossal duct.
Anomalies of the thyroglossal duct and thyroid gland
thyroglossal cysts – located at the midline
Relationships of the thyroid gland
- Trachea
- Cricoid
- Infrahyoid muscles
- Lateral to the esophagus
- Recurrent laryngeal nerve
- Internal jugular vein, common carotid and vagus (lateral)
At which vertebral level does the cricoid finish?
C6
Where does the inferior thyroid artery branch from?
From the thyrocervical trunk (which comes from the subclavian artery).
Venous drainage of the thyroid gland
Inferior, middle and superior thyroid vein
On what system do the visceral fibers of the PS in glands act?
They control smooth muscle, they stimulate secretion
What kind of gland is the thyroid gland?
Endocrine as it releases hormones.
How are the sympathetic fibers (which come from the sympathetic trunk) that accompany vessels to the thyroid gland?
They are only vasomotor
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.
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.
Origin of external auditory meatus
1st pharyngeal cleft
Typical location of lateral cervical cysts
Along the medial border of the sternocleidomastoid muscle
What are the derivatives of the pharyngeal pouches?
Enlargements of the endodermal lining of the PAs
What does the 1st pharyngeal pouch develop into?
pharyngotympanic tube & tympanic membrane
What does the 2nd pharyngeal pouch develop into?
Palatine tonsil
What does the 3rd pharyngeal pouch develop into?
inf parathyroid glands, C cells and thymus
What does the 4th pharyngeal pouch develop into?
Superior parathyroid glands
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.
Name the three greater salivary glands
Parotid, submandibular and sublingual
Name the lesser salivary glands
Palatine, buccal, labial, palatoglossal & lingual
Relationships of the parotid gland
external carotid artery and retromandibular vein
Parotid duct=
Stenon’s duct (se puede observar en espejo)
Where is the opening of the submandibular duct?
Sublingual papilla
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
- Parotid gland – fibers that travel with the lesser petrosal nerve (IX CN) - otic ganglion- auriculotemporal nerve (V3)
- Submand/sublingual glands– fibers that travel with the chorda tympani (VII) – lingual nerve (V3) - submandibular ganglion
- Palatine and nasal mucosa - fibers that travel with the greater petrosal (VII) - nerve of the pterygoid canal -pterygopalatine ganglion
- 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:
- Mylohyoid
- Lingual nerve
- Submandibular gland
- 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
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
Anterior
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)
Inferior alveolar nerve recovers sensory info from…
Inferior teeth
The lingual nerve accompanies the… into the oral cavity
Submandibular duct
Cutaneous territory of V3
Mandibular and mental regions, inferior aspect of auricle and temporal region
Summary of the mandibular division of the trigeminal nerve
The infratemporal fossa is supplied by branches of the …
Maxillary artery
All V3 nerves are supplied by a branch of the maxillary artery except the …
Lingual nerve, the lingual artery comes off directly from the external carotid.
Venous drainage of the infratemporal fossa
Visceral efferent branches of the lesser petrosal (IX PS) which synapse in the OTIC ganglion, travel within the … to reach the parotid gland
Auriculotemporal nerve
External carotid artery bifurcates into supratemporal and maxillary within the…
Parotid gland
