GI anatomy 2 Flashcards
Which nerve/s are the muscles of mastication supplied by?
Mandibular division of Trigeminal nerve= CN5 V3
V3- Mandibular divison
Which of the muscles of mastication are used to close the mouth?
- Temporalis
- Masseter
- Medial Pterygoid
Which muscle of mastication is used to open the mouth?
Lateral Pterygoid
Where does the Trigeminal nerve originate? (CNS part)
Pons
Where is the intracranial part of the trigeminal course?
inferior to edge of Tentorium cerebelli
Where is the base of the foramen part of the trigeminal course?
Sphenoid bone
Foramen ovale
Where is the extra cranial part of the trigeminal course?
From foramen ovale to part of the body supplied
Why are loose teeth or parts are a risk?
Choking hazard, aspiration risk
What is aspiration? Why is it dangerous?
Inhalation of liquid or solid matter into lungs. Potential infection
Which part of the CNS does the facial nerve come from?
Junction between pons and medulla
Where is the intracranial part of the facial nerve
internal acoustic meatus (in posterior cranial fossa)
Where is the base of the foramen part of the facial nerve?
Temporal bone
Where is the extra cranial part of the facial nerve?
Stylomastoid foramen
Facial nerve cranial number?
VII
What is the Chorda Tympani? What is its function?
Branch of facial nerve- connects to the lingual nerve (branch of trigeminal)
Why is the innervation of the Chorda Tympani significant?
Gives taste to anterior 2/3rds of tongue.
Parasympathetics
Other functions of facial nerve? (3)
- Supplies muscle of facial expression
- Supplies sublingual salivary gland
- Parasympathetics supply submandibular salivary gland
Which parts of the upper and lower oral cavity are sensitive to touch? Which nerve innervate them?
- Superior half- Gingiva, hard palate. CN V2
2. Inferior half- Gingiva, floor of mouth. CN V3
Which part of the oral cavity is very sensitive to touch?
Posterior wall of oropharynx
What is the gag reflex?
Protective reflex that prevents foreign bodies entering the Larynx or pharynx
Which CN is the sensory part of the gag reflex carried out by?
CN IX
Which CN is the motor part of the gag reflex carried out by?
CN IX,X
What is the reflex of the posterior oropharynx to touch?
Constriction of the oropharynx. Body closes it off to contact
Using an endoscope can cause these areas to come into contact? How is this dealt with?
Local anaesthesia blocks sensory AP’s of CN V2,V3 CN VII, IX
What is CN V2?
Maxilliary division of the trigeminal nerve
Course of this division is same as V3 except in which two areas?
- Base of skull foramen- sphenoid bone
Foramen Rotundum - Extracranial part- from foramen rotudum to part supplied
Which nerve is CN IX?
Glossopharyngeal
What is the course of CN IX in terms of:
- CNS origin
- Intracranial part
- Base of skull foramen
- Extracranial part?
- Medulla
- Jugular Foramen (in posterior cranial fossa)
- Jugular foramen- junction between temporal and occipital bone
- Posterior wall of oropharynx
Parasympathetic stimulation- parotid
Which nerve innervates the muscles (intrinsic/extrinsic) of the tongue?
Hypoglossal (CN XII)
What are the 4 extrinsic muscles of the tongue? (glossus)
- Styloglossus
- Palatoglossus
- Hyoglossus
- Genioglossus
Which of the 4 is the only muscle not to be supplied by CN XII?
Palatoglossus
What is the course of the hypoglossal nerve?
- CNS part- medulla
- Base of skull foramen- occipital bone
- Extra-cranial part- most muscles of tongue
The contraction of the constrictor muscles of the pharynx are sequential. T/F?
True
Which CN innervates the Circular muscles of the pharynx?
CN X- Vagus
Which CN supplies the longitudinal muscles of the pharynx?
CN X, XI
Which muscle and which CN closes the lips to prevent drooling?
Orbicularis Oris and CN VII
Which CN causes the tongue to push the bolus down posteriorly to the oropharynx?
CN XII- Hypoglossal
Which CN causes the constrictor muscles of the pharynx to contract to push bolus down to oesophagus?
CN X
Which CN innverates the inner longitudinal muscles to raise the larynx, shorten the pharynx and close the laryngeal inlet preventing aspiration?
CN IX,X
What vertebral level does the oesophagus begin?
Vertebral level C6- Circopharyngeus muscle
What is the mechanical difference between the two oesophageal sphincters?
- Upper- anatomical
2. Lower- physiological
Function of oesophageal plexus?
Innervates muscles of the oesophageal wall
What are three anatomical points of contact of the oesophagus?
- Root of neck- posterior to trachea
- Chest- posterior to heart. in contact with Left Atrium
- In abdomen- through diaphragm, connects with stomach
role of lower oesophageal sphincter?
Prevents reflux
What 3 regions does the stomach cover?
- Left hypochodrium
- Epigastric
- Umbilical
At which point of the stomach does oesophageal emptying take place?
Cardia
Structure lying just in front of the pyloric sphincter?
Pyloric Antrum
