Anatomy of the upper GI tract Flashcards
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:
- Elevates the mandible
- 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:
- Pulls mandibular head forward toward articular tubercle
- Lower the mandible to open
Describes the Artiuclar disc of the tempomandibular joints
- Location - between codylar process and mandibular fossa
- Divides two cavities
- Superior cavity: for Translation- codyl and disc move out of socket
- 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)
Supply
- 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
