Anatomy of the upper GI tract Flashcards Preview

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Flashcards in Anatomy of the upper GI tract Deck (46):

What are the functions of GI tract

  • Mastication - TMJ, muscle of the TMJ, face, tongue and dentition 
  • Deglutition - Tongue, palate, phranyx and oesophagus 
  • Taste- Mastication, Salivation and tongue 
  • Salivation - Parotid gland, submandibular, subligual 



What is the process of Mastication 

  • Process of chewing and increaing surface area of food 
  • Movement of TMJ and tongue
  • Facilitates taste and digestion by mixing food with saliva


What is the Buccinator muscle 

  • Cheek muscle 
  • When put food inside mouth the cheek pushes medially inside mouth 


How many teeth do adults have 

  • ​32 teeth 
  • 16 upper and 16 lower 


How many Quandrants are adult teeth divided into 

four quadrants

  • Upper left and right
  • Lower left and right 


What are the different types of dentition 

  • Incisor - Number 1 and 2 - cutting food - sharpe
  • Canine- Number 3 - peircing and ripping teeth 
  • Pre-molars - Number 4 and 5
  • Molars - Number 6, 7 and 8 


Where the parotid gland drains its contents and dumps its saliva in the mouth


2nd maxillary molar 


Describes the TMJ

  • Mandible + temporal bones 
  • Mandibular fossa in the Temporal bones where for mandibular condylar process
  • Artericular tubercle is a process on zygomatic arch and lies anreries to the TMJ joint 



What happens when the jaw is dilocated 

  • TMJ is pushed anteiror to the articular tubercle 
  • jaw cannot close 


How many muscles of mastication and what are they?

There are 4 muscles of mastication - 3 closes jaw 1 opens jaw 

  • Temporalis muscle
  • Masseter
  • Medial petrigoid 
  • Lateral Petrigoid - Opens jaw


What is the nerve supply to the muscles of mastication 

Mandibular devision of the Trigemintal nerve - CN V3


Temporalis - Origin, insertion and function

  • From Temporal fossa to the coronoid process of the mandible 
  • Function: pulls jaw up to close it 


Masseter: orgin, insertion and function 

Has two parts - Superficial part and Deep part 

  • Geos from the angle of madible to the zygomatic arch 
  • Function: 
  1. ​Elevates the mandible
  2. Protrusion 


Medial Pterygoid: orgin, insertion and function

  • Geos from the Deep angle of the mandible to the pterygoid plates of sphenoid bone 
  • Function: Closes jaw and protrusion 
  • Mimic masseter on internal surface


Lateral Pterygoid: function, origin and insersion 

  • Geos from the mandibular condyl to the pterygoid plates of sphenoid 
  • Function: 
  1. ​Pulls mandibular head forward toward articular tubercle 
  2. Lower the mandible to open 


Describes the Artiuclar disc of the tempomandibular joints 

  • Location - between codylar process and mandibular fossa 
  • Divides two cavities
  1. ​Superior cavity: for Translation- codyl and disc move out of socket
  2. Inferior cavity: for Rotation 

Muscle attachment - Attaches to the lateral pterygoid anteriorly 

  • Which pulls the condyle and disc forward 


Describes the course of the mandibular division of the Trigemeninal nerve 

  • Function: supplies sensory and motor fibers to the mandible
  • Comes off the Pons (only trigeminal nerve does this) 
  • Goes through Foramen Ovale 
  • To muscles of mastication 


What is the anatomy of the Oral cavity 


What is the Surface anatomy of the oral cavity

  • Tonsils are lymphoid tissue- located between the 2 arches of the soft palat 
  • Uvula extends down from the soft palate
  • Gingiva - mucosa covering dentition - inflammation of this causes gum disease


what are the 2 different divsions of the tongue and what separates these two parts

Sulcul terminalis - divides the 2 parts

Part 1 - Anterior 2/3rd 

  • Horizontal part
  • Located in oral cavity 
  • Taste - CNVII 
  • General sensation CN V3 

Part 2: Posterior 1/3rd 

  • Verticle part 
  • Located in oropharnyx 
  • Generate sensation and taste - CN X


What are the types of Papilla in the tongue 

  • Follate papilla
  • Vallate papilla
  • Fungi-form papilla 
  • Filliform papilla - no taste only 1 

- Tip of the tongue for temperature and touch only 


Decribes the cource of the Facial nerve CN VII

  • Function: special sensory, sensory, motor and parasympathetic 
  • Comes of the pontomedullary junction (line between pons and inferior medulla)
  • Travels through tepora-bone via Acuostic meatus 
  • Exits through the Stylomastoid foramen 


What does the Facial nerve CN VII supply 

  • Taste - 2/3 anterior tongue
  • Muscles of fascial expression 
  • Glands in floor of the mouth - submandibular and sub-parotid 


How can the facial nerve pick up tast fibres 

As it leaves the Stylomastoid foramen it’s going to course down deep to mandible and head towards the tongue going through the middle ear-  (now called Chorda tympani) will take taste fibers and parasympathetic to Sub-mandibular and sub- lingual –Connects to the Lingual nerve which comes from the Mandibular division of the Trigeminal nerve CNV3 – That’s how its able to pick up taste fibers from anterior 2/3 parts of the tongue

  • Picks up taste aswell as bring parasympathetic fibers to the glands of the mouth for salivation 


What are the sensations in the oral cavity 

Superior half 

  • Gingiva and palate - supplies by maxillary divsion of trigeminal nerve
  • CN V2 

Inferior half

  • Gingiva and floor of mouth 
  • CNV3 

Intra-cranial lesions which losses sensation in upper or lower part of mouth can tell us which nerve is affected 


What is the Gag-reflex 

Protective mechanism which prevents foriegn bodies form entering the pharynx and the larynx 


What are the Sensory and motor parts of the gag-reflex arch

  • Sensory part of the arch - Nerve fibres withing CN IX (glossophyrngeal never) 
  • Motor part of arch - Nerve fibres within CN IX and CNX 


Part of the reflex arch is constriction of the phyrnx to prevent entry on foriegn bodies 


What is it important to Anesthesise this area 

To allow insertion of endoscope 

Spraying a local anesthetic will block sensory action potentials in CN V2, CN V3, CN VII and CN IX 


What is the cource of Maxillary division of the Trigeminal nerve - CN V2 

Carries sensory fibres 

  • From Pons
  • Through Foramen Rotundum 
  • To sensory area - mid face


What is the course of the Glossopharyngeal nerve CN IX 

  • From Medulla 
  • Through Jugluar foramen (Also CN X and CN XI)


  • Motor - posterior wall of oropharynx 
  • Motor - Parotid gland 
  • Sensation and taste - posterior 1/3rd of the tongue 


Describe the surface anatomy of the Salivary-Glands 


What happens if the glands are clogged of block 

  • ​Swells up due to back up of secretions 
  • Swells up when hungry and can cause pain if calcified 


How is the tongue positioned in the oral cavity 

Suspended in the oral cavity by 4 pairs of skeletal muscles 


What are the Extrinsic mucle of the tongue and whats their function

  • 4 pairs- lay outside- skeletal mucle 
  • Function - changes position of the tongue during mastication, swallowing and speach 


Name the 4 extrinsic mucles 

  • Genioglossus - chin muscle 
  • Hyogliossus - hyoid bone
  • Palatoglossus - soft palat 
  • Styloglossus - stylo-process 


What is the nerve innervation to extrinsic mucles 

all apart from platatoglossus -

 are supplied by CN XII (hypoglossel nerve)

Motor fibres to tongue extrinsic mucles 


What is course of the Hypoglossel nerve CN XII 

  • From the Medulla 
  • Through hypoglossal canal 
  • Motor fibres -  to extrinsic and intrinsic mucles of the tongue


What are the intrinsic mucles of the tongue 

  • Also 4 pairs
  • locate dorsally/posteriorly 
  • Function: modifies shape of the tongue during mastication


What is the course of the hypoglossle nerve- CN XII

  • motor only! 
  • From medulla
  • Exits skill at hypoglossel canal
  • To intrinsic and extrinsic muscle of the tongue except palatoglossus 


What are the muscle of the pharynx 

  • 3 constrictor circular muscles- superior, middle and inferior
  • Contract from superior to inferior sequentially -insert into midline ruffle 
  • All supplied by the Vagus nerve - CN X


What is the Cricopharyngeus 

  • Upper oesophageal Sphincter 
  • location: C6 
  • Circular muscle of the pharynx 


What are the longitudinal muscle of the pharynx 

  • 3 muscle fibres - 
  • Inervation: Vagus never - expect Stylophyarngeus (CN IX)
  • Function: both layers elevate pharynx and larynx 
  • Contract to shorten pharynx - swallowing 
  • Raise larynx to close over the laryngeal inlit - stops aspiration of food 


What is the Paraphyrangeal spacev 

  • Lateral neck space shaped like an inverted cone- base at skull, apex at hyoid 
  • Symphathetic chain 
  • Common carotid
  • CNX 
  • any injury to pharynx can affect these vessels


What is the process of swallowing 


Put food in mouth open oral cavity – chew food using dentition and use tongue to move food form side to side. Then tongue ripples to push food back towards the oropharynx. Soft palate is elevated – don’t want food to enter the nasopharynx- And larynx is elevated to flap epiglottis close prevent aspiration of food – constrictor muscles squeeze food down the pharynx – upper esophageal sphincter relaxes and esophagus receives the food


What is the process of swallowing in-terms of nerve involved