Which nerve innervates all muscles of facial expression?
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The motor branch of the facial nerve (CN VII).
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Which nerve innervates all muscles of facial expression?
The motor branch of the facial nerve (CN VII).
How do skeletal motor fibers of the facial nerve enter the facial canal?
Via the internal acoustic meatus.
What direction do the skeletal motor fibers turn at the genu of the facial canal?
They turn posteriorly.
What muscles primarily elevate the mandible?
The masseter and medial pterygoid muscles.
Where do the skeletal motor fibers exit the facial canal?
Via the stylomastoid foramen.
What role does the temporalis muscle play in the elevation of the mandible?
The anterior fibers of the temporalis muscle can also elevate the mandible.
What shape does the submandibular gland have?
C-shaped.
What primarily causes the depression of the mandible?
Largely a function of gravity.
What happens to the motor branch after it emerges from the stylomastoid foramen?
It enters the parotid gland and ramifies into several named branches.
Where does the submandibular gland wrap around?
The posterolateral free edge of the mylohyoid muscle.
What are the major salivary glands involved in saliva production during the oral preparatory phase?
Parotid, submandibular, and sublingual salivary glands.
Which muscle is involved in the depression of the mandible if muscle action is needed?
The lateral pterygoid muscle (inferior head) and suprahyoid muscles of the neck.
What areas do the branches of the motor branch of the facial nerve distribute to?
Muscles of facial expression in the face, neck, and scalp.
Where does the duct of the submandibular gland open?
On the frenulum of the tongue.
Where is the parotid gland located?
Lateral and posterior to the mandibular ramus and masseter muscle, and anterior to the external ear.
Where are the muscles of facial expression located?
In the superficial face, neck, and scalp.
What muscle is most capable of protruding the mandible?
The lateral pterygoid muscle (superior head).
What is the primary function of the muscles of mastication?
To bring the mandibular dentition into occlusion with that of the maxilla.
Which nerve carries preganglionic parasympathetic neurons to the submandibular gland?
The chorda tympani branch of the facial nerve (CN VII).
How does the duct of the parotid gland function?
It emerges from the anterior surface, crosses superficially in the face, and opens in the vestibule of the mouth adjacent to the second maxillary molar.
What do the muscles of facial expression arise from?
Bone or ligaments.
How does the medial pterygoid assist in the protrusion of the mandible?
It can assist the lateral pterygoid in this action.
What role does the bolus play during chewing?
It is placed between the occluding mandibular and maxillary dentitions to be reduced in size and consistency for swallowing and digestion.
What is the location of the sublingual salivary gland?
In the floor of the mouth, deep to the mucosa and lateral to the lingual frenulum.
What role does the tongue play during chewing?
It keeps ingested food between the occluding teeth.
Which cranial nerve carries preganglionic parasympathetic neurons to the parotid gland?
Glossopharyngeal nerve (CN IX).
What is the primary function of the muscles of facial expression?
To produce facial expressions and serve as sphincters for the eyes, mouth, and nasal cavity.
Which muscle retracts the mandible?
The posterior fibers of the temporalis muscle.
Where does the masseter muscle extend from and to?
From the inferior surface of the zygomatic arch to the lateral surface of the angle, ramus, and coronoid process of the mandible.
What is the primary function of the tongue in preparation for swallowing?
Positioning the bolus in the mouth.
How do the ductules of the sublingual gland function?
They open directly into the sublingual fold.
Where do the preganglionic parasympathetic neurons for the parotid gland synapse?
In the otic ganglion.
What is the role of the buccinator muscle?
It forms the skeleton of the cheek and maintains muscular tension in the cheeks.
What is the origin of the temporalis muscle?
From the floor of the temporal fossa of the skull and the overlying temporalis fascia.
Where do preganglionic parasympathetic neurons for the sublingual gland synapse?
On the submandibular ganglion in the floor of the mouth.
What are the two groups of tongue musculature?
Intrinsic and extrinsic muscle groups.
How do postganglionic parasympathetic neurons reach the parotid gland?
By joining the auriculotemporal nerve of the mandibular nerve.
Which nerve innervates all muscles of facial expression?
The motor branch of the facial nerve (CN VII).
What are the two heads of the lateral pterygoid muscle?
One arises from the lateral surface of the lateral pterygoid plate of the sphenoid bone, and the other from the greater wing of the sphenoid.
What is dysphagia?
A general term used to describe difficulty in swallowing.
What do intrinsic tongue muscles do?
Alter the shape of the tongue.
What is the role of minor salivary glands?
They are scattered throughout the oral mucosa and submucosa, contributing to saliva production.
What is the function of the orbicularis oris muscle?
It is the primary sphincter muscle of the mouth and lips, preventing drooling and maintaining oral competence.
Where do the heads of the lateral pterygoid muscle attach?
To the capsule and articular disc of the TMJ, and the surrounding bone of the mandibular condyle.
What is the function of extrinsic tongue muscles?
Move the tongue within the oral cavity.
What are common causes of dysphagia?
Ingestion of foreign bodies, cricopharyngeal achalasia, laryngeal or pharyngeal cancer, stroke, and various skeletal muscle diseases.
How does the buccinator muscle aid in the oral preparatory phase?
It prevents ingested food items from collecting in the vestibule of the mouth.
Where does the medial pterygoid muscle arise from?
From the medial surface of the lateral pterygoid plate to the surface of the angle, ramus, and coronoid process of the mandible.
Where do foreign bodies typically lodge in the pharynx?
In the piriform recess.
Which cranial nerve innervates most of the tongue muscles?
Hypoglossal nerve (CN XII).
What are the two mechanisms for airway closure during swallowing?
Closure of the laryngeal inlet and closure of the glottis.
Which extrinsic muscle of the tongue is innervated by a different cranial nerve?
Palatoglossus, innervated by CN X.
What is cricopharyngeal achalasia?
A condition where a prominent cricopharyngeus muscle fails to open adequately, causing dysphagia.
What primarily produces the closure of the laryngeal inlet?
Active contraction of the suprahyoid musculature.
What is a common symptom of laryngeal or pharyngeal cancer?
Painful swallowing.
Where does the hypoglossal nerve exit the cranial cavity?
Via the hypoglossal foramen in the anterolateral aspect of the foramen magnum.
What happens to the epiglottis during the elevation of the laryngeal apparatus?
It is elevated and pressed against the posterior aspect of the tongue.
How does stroke affect swallowing?
It can lead to swallowing difficulty, with most patients recovering within one week.
What additional fibers does the hypoglossal nerve carry while in the neck?
Fibers from the C1 spinal nerve.
What is the effect of the contact between the epiglottis and the pharyngeal tongue?
The epiglottis bends posteriorly (retroflex) over the laryngeal inlet.
What occurs at the end of the oral preparatory phase?
Voluntary movements of the tongue position the food bolus against the uvula of the soft palate.
What are some diseases that can cause dysphagia?
Amyotrophic lateral sclerosis (ALS), Parkinson’s disease, multiple sclerosis, muscular dystrophy, and myasthenia gravis.
How long does the oral phase of swallowing last?
Approximately one second.
What is the role of the retroflexed position and beaked shape of the epiglottis?
To drive the swallowed bolus into the piriform recesses of the laryngopharynx.
What can happen with brainstem strokes regarding swallowing?
They can lead to persistent impairment of glottis closure and loss of coordination of muscular activity during swallowing.
What triggers the pharyngeal phase of swallowing?
The glossopharyngeal nerve when the food bolus contacts the posterior third of the tongue.
What triggers a strong cough response during swallowing?
Contact of fluids or foods with the mucosal surfaces of the laryngeal inlet.
What is velopharyngeal closure?
The elevation of the soft palate and uvula to close off the nasopharynx.
Which nerves provide sensory innervation for the cough reflex?
The internal and recurrent laryngeal nerves.
What role does pharyngeal peristalsis play during swallowing?
It assists in velopharyngeal closure and propels the bolus through the oropharynx.
What is the role of the laryngeal musculature during swallowing?
To tightly adduct the vocal ligaments to prevent aspiration of the bolus.
What happens at the cricoarytenoid joints during swallowing?
They rotate or glide the arytenoid cartilages, resulting in adduction of the vocal ligaments.
What happens to the airway during the pharyngeal phase?
The airway closes to prevent aspiration of the swallowed bolus.
What is the function of the upper esophageal sphincter during swallowing?
It actively dilates to allow the bolus to pass from the pharynx into the upper esophagus.
What is the role of the glossopharyngeal nerve in the gag reflex?
It is the afferent limb of the gag reflex.
How can the vagus nerve be tested?
By asking the patient to produce an 'ahh', 'zah', or 'kah' sound.
Which nerve innervates all four muscles of mastication?
The mandibular nerve (CN V3).
What happens during the esophageal phase of swallowing?
The bolus is propelled through the thoracic esophagus via peristaltic contractions.
What is unique about the mandibular nerve compared to other divisions of the trigeminal nerve?
It carries efferent fibers to skeletal muscles.
How does the mandibular nerve enter the infratemporal fossa?
Via the foramen ovale of the middle cranial fossa.
What is the duration of esophageal transit?
Varies from 8 to 20 seconds.
What type of fibers does the otic ganglion associated with the mandibular nerve carry?
Parasympathetic fibers.
What areas do the sensory branches of the mandibular nerve supply?
Face, scalp, cranial dura, and oral cavity.
What is deglutition?
The act of swallowing.
What does the auriculotemporal nerve provide sensory innervation to?
Skin anterior to the ear and the skin over the temple.
What are the three phases of deglutition?
Oral, pharyngeal, and esophageal.
What is the function of the inferior alveolar nerve?
Provides sensory innervation from the teeth and gingivae of the lower jaw.
Where does the inferior alveolar nerve enter the mandible?
At the mandibular foramen.
What occurs during the oral preparatory phase?
Ingested food is processed into a semisolid state, known as the 'bolus', with the help of salivary secretions.
What does the mental nerve innervate?
The skin of the chin.
What role do salivary glands play in the oral preparatory phase?
They secrete fluids that begin the digestion of carbohydrates and fats.
What area does the lingual nerve provide sensory innervation to?
The mucosa covering the anterior 2/3 of the tongue.
What is the function of the temporomandibular joint (TMJ) during chewing?
It allows for the movement of the mandible necessary for processing food.
What are the two components of the TMJ?
Right and left articulations between the mandible and the temporal bones.
What actions are permitted by the superior capsule of the TMJ?
Anterior and posterior gliding movements of the mandibular condyle, recognized as protrusion and retraction.
What actions are permitted by the inferior capsule of the TMJ?
Rotation of the condyle against the articular disc, recognized as depression and elevation of the mandible.
