Session 4: Oral Cavity and Upper GI Tract Flashcards
List the three sets of tonsils found in the upper GI tract
Palatine, Pharyngeal, Lingual
Between which two folds do the palatine tonsils lie?
Palatopharyngeal Fold Palatoglossal Fold
Why does the GP gets you to say ‘aaaaaah’ when he inspects the inside of your mouth?
It raises the soft palate and uvula and depresses the tongue, which arevagus-mediated effects. So the GP is testing the motor function of the vagus nerve.
Describe the borders of the pharynx.
Base of the skull and the inferior border of the cricoid cartilage
What are the three parts of the pharynx and what are their borders?
Nasopharynx – down to the soft palate (pharyngeal isthmus) Oropharynx – between the soft palate and the epiglottis Laryngopharynx – between the epiglottis and the cricoid cartilage
What happens to the epiglottis when you swallow?
Retroflexion to cover the laryngeal inlet
What is the role of the soft palate in swallowing?
It elevates to close off the nasopharynx so that food doesn’t go into the nasal cavity
What is the Piriform Fossa and what is its clinical significance?
The piriform fossae are depressions on either side of the laryngeal inlet where food (commonly fish bones) get stuck
Which muscles aid the passage of a bolus of food down the oesophagus?
Superior, middle and inferior pharyngeal constrictor muscles
Which nerves provide sensory innervation of the pharyngeal wall?
Glossopharyngeal and Vagus (pharyngeal plexus)
Which nerves provide motor innervation of the pharyngeal constrictor muscles?
Vagus (and a bit of accessory)
Describe the changes that occur during swallowing.
Lift and retract the tongue (styloglossus and intrinsic muscles) Bolus into oropharynx (palatoglossus) Close off nasopharynx by raising soft palate Raise the larynx – closed off by the epiglottis Peristaltic wave of constrictor muscles Relax cricopharyngeus, open oesophagus
Name the three salivary glands, describe their secretions and state the nerves that provide secretomotor innervation to them.
Parotid – serous – glossopharyngeal Submandibular – serous – facial Sublingual – mucous – facial
Which muscle does the parotid duct pierce and where does it open into the buccal cavity?
Buccinator It opens next to the second upper molar
Name the main muscles of the tongue. Which nerve innervates all of this?
Genioglossus, Hyoglossus, Styloglossus Intrinsic Muscles These are all innervated by the hypoglossal nerve
What other muscle is associated with the tongue but isn’t innervated by this nerve?
Palatoglossus – it is innervated by the vagus
What tongue movements do the genioglossus and styloglossus perform?
Genioglossus – protracts the tongue Styloglossus – retracts and elevates the tongue
To which side would the tongue move if a patient with a unilateral lesion in the hypoglossal nerve was asked to stick their tongue out?
Towards the side of the lesion because the genioglossus is used in protracting the tongue
What movement is palatoglossus responsible for?
Elevates the soft palate and moves the back of the tongue upwards
Where is the lingual nerve relative to the hypoglossal nerve?
Lingual nerve is superior to the hypoglossal nerve
Describe the sensory innervation of the tongue
Anterior 2/3 sensation – mandibular branch of trigeminal Anterior 2/3 taste – facial Posterior 1/3 everything – glossopharyngeal
To which structure in the brainstem do the neurons of taste go? It is considered the main taste centre within the brainstem.
Nucleus Solitarius
State the origin and insertion of the masseter and the movement that it is responsible for.
Zygomatic Arch Lateral surface of the ramus of the mandible and the angle of the mandible Elevates the mandible (allows forced closure of the mouth)
State the origin and insertion of temporalis and the movement that it is responsible for.
Temporal Fossa Coronoid Process Elevates and retracts mandible
State the origin and insertion of the medial and lateral pterygoid muscles and the movements that they are responsible for.
Lateral – lateral pterygoid plate (and greater wing of sphenoid) TO neck of the mandible Medial – lateral pterygoid plate, maxilla, palate TO angle of the mandible Lateral – Movement – depresses and protracts mandible to open the mouth Medial – Movement – elevates, protracts and lateral movement of mandible for chewing
Describe the structure of the temporomandibular joint.
- it is a capsular joint
- The capsule has an articular plate splitting it into two
- The head of the mandible articulates with the articular tubercle of the temporal bone
Describe the movements around the temporomandibular joint when opening the mouth.
When opening the mouth slightly there is a hinge action When the mouth is opened further, the head of the mandible glidesanteriorly on the articular tubercle of the temporal bone
State the eight branches of the external carotid artery.
Inferior to superior
- Superior Thyroid
- Ascending Pharyngeal
- Lingual
- Facial
- Occipital
- Posterior Auricular
- Maxillary
- Superficial
“Some Anatomists Like Freaking Out Poor Medical Students”
At the level of what anatomical landmark does the common carotid artery bifurcate.
At the level of the laryngeal prominence
Why does the facial artery have a wavy course across the mandible?
If it were taut, then when the mouth is opened the facial artery wouldrupture
Which branch of the external carotid artery gives rise to the middle meningeal artery?
Maxillary
Through which foramen does the middle meningeal artery enter the skull?
Foramen Spinosum
State the five branches of the facial nerve
Temporal Zygomatic Buccal Mandibular Cervical
What are the two main branches of the mandibular branch of the trigeminal nerve?
Lingual Nerve Inferior Alveolar Nerve
What are the functions of the lingual and inferior alveolar nerve?
Inferior Alveolar – innervates the lower teeth (this is the one that is stimulated in tooth ache) Lingual – sensation (touch and taste) to the anterior 2/3 of the tongue AND secretomotor to the sublingual and submandibular salivary glands
What fibres join the lingual nerve?
Some fibres of the facial nerve via the Chorda Tympani (this is why the lingual nerve is responsible for taste)
Which cranial nerve provides all sensory innervation of the face?
Trigeminal Nerve
How many arteries and veins does the thyroid gland have?
2 pairs of arteries 3 pairs of veins
State where these arteries and veins originate from and drain to.
Superior thyroid artery – from the external carotid artery Inferior thyroid artery – from the thyrocervical trunk Superior thyroid vein – to the internal jugular vein Middle thyroid vein – to the internal jugular vein Inferior thyroid vein – to the brachiocephalic vein
Which muscle protects the carotid sheath when the head is turned?
Sternocleidomastoid
What is Bell’s Palsy and how may it present in a patient?
Facial nerve palsy Inability to contract muscles of facial expression and altered taste
Which nerves innervate the following muscles: a. Temporalis b. Masseter c. Buccinator d. Medial and Lateral Pterygoids e. Pharyngeal Constrictors f. Digastric g. Mylohoid
a. Temporalis Mandibular (trigeminal) b. Masseter Mandibular (trigeminal) c. Buccinator Buccal (facial) d. Medial and Lateral Pterygoids Mandibular (trigeminal) e. Pharyngeal Constrictors Sensory = Glossopharyngeal (IX) + Vagus (X) Motor = Vagus (X) (and a bit of Accessory (XI)) f. Digastric Anterior belly = Mandibular (trigeminal) Posterior belly = Facial g. Mylohyoid Nerve to mylohyoid – branch of inferior alveolar nerve (which is a branch of the mandibular)
What are the branches coming off the inferior alveolar nerve?
Mental nerve – terminal branch (provides sensation to the front of the chin) Nerve to mylohyoid
What is the vallecula?
Depression just behind the root of the tongue – they serve as spit traps Saliva is temporarily held in the valleculae to prevent initiation of the swallowing reflex
What are the full numbers in a typical permanent set of teeth?
32 16 upper and 16 lower 8 incisors, 4 canines, 8 premolars and 12 molars (including 4 wisdom teeth)
How many deciduous (baby) teeth are there?
20
Which teeth are missing in the deciduous set compared to the adult set?
No premolars or wisdom teeth
When do the first deciduous teeth erupt?
Around 6 months
When is the deciduous set usually complete?
Around 20-24 months
What are the approximate starting and completion ages for the permanent set of teeth?
Starts around 7 years and usually completed by the age of 21
Why are the tonsils clinically important?
They are areas of lymphoid tissue so they can get infected and inflamed
What is the simplest test of the glossopharyngeal nerve?
Test the patient’s gag reflex by sticking something down their throat
How is the hypoglossal nerve tested?
Ask the patient to stick their tongue out
How is the trigeminal nerve tested?
Sensory – touch the patient around the jawline, on the cheek and on the forehead (to test the three divisions) Motor – ask the patient to clench their teeth and try to palpate the bulge of the masseter and temporalis
How is the facial nerve tested?
Ask the patient to crease up their forehead by raising their eyebrows Ask the patient to keep their eyes closed against resistance
