Anatomy of the upper GI tract

Question 1

What are the functions of GI tract

Answer 1

• 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

Question 2

What is the process of Mastication

Answer 2

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

Question 3

What is the Buccinator muscle

Answer 3

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

Question 4

How many teeth do adults have

Answer 4

• ​32 teeth
• 16 upper and 16 lower

Question 5

How many Quandrants are adult teeth divided into

Answer 5

four quadrants

• Upper left and right
• Lower left and right

Question 6

What are the different types of dentition

Answer 6

• 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

Question 7

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

Answer 7

2nd maxillary molar

Question 8

Describes the TMJ

Answer 8

• 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

Question 9

What happens when the jaw is dilocated

Answer 9

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

Question 10

How many muscles of mastication and what are they?

Answer 10

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

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

Question 11

What is the nerve supply to the muscles of mastication

Answer 11

Mandibular devision of the Trigemintal nerve - CN V3

Question 12

Temporalis - Origin, insertion and function

Answer 12

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

Question 13

Masseter: orgin, insertion and function

Answer 13

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

Question 14

Medial Pterygoid: orgin, insertion and function

Answer 14

• 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

Question 15

Lateral Pterygoid: function, origin and insersion

Answer 15

• 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

Question 16

Describes the Artiuclar disc of the tempomandibular joints

Answer 16

• 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

Question 17

Describes the course of the mandibular division of the Trigemeninal nerve

Answer 17

• 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

Question 18

What is the anatomy of the Oral cavity

Answer 18

Question 19

What is the Surface anatomy of the oral cavity

Answer 19

• 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

Question 20

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

Answer 20

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

Question 21

What are the types of Papilla in the tongue

Answer 21

• Follate papilla
• Vallate papilla
• Fungi-form papilla
• Filliform papilla - no taste only 1
• Tip of the tongue for temperature and touch only

Question 22

Decribes the cource of the Facial nerve CN VII

Answer 22

• 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

Question 23

What does the Facial nerve CN VII supply

Answer 23

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

Question 24

How can the facial nerve pick up tast fibres

Answer 24

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

Question 25

What are the sensations in the oral cavity

Answer 25

**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

Question 26

What is the Gag-reflex

Answer 26

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

Question 27

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

Answer 27

* **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**

Question 28

What is it important to Anesthesise this area

Answer 28

To allow insertion of endoscope ## Footnote Spraying a local anesthetic will block sensory action potentials in **CN V2, CN V3, CN VII and CN IX**

Question 29

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

Answer 29

**Carries sensory fibres** * **From Pons** * Through **Foramen Rotundum** * To **sensory area - mid face**

Question 30

What is the course of the **Glossopharyngeal nerve CN IX**

Answer 30

* 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

Question 31

Describe the surface anatomy of the Salivary-Glands

Answer 31

Question 32

What happens if the glands are clogged of block

Answer 32

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

Question 33

How is the tongue positioned in the oral cavity

Answer 33

**Suspended** in the oral cavity by **4 pairs of skeletal muscles**

Question 34

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

Answer 34

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

Question 35

Name the **4 extrinsic mucles**

Answer 35

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

Question 36

What is the nerve innervation to **extrinsic mucles**

Answer 36

all apart from **platatoglossus -** are supplied by **CN XII (**hypoglossel nerve) Motor fibres to tongue extrinsic mucles

Question 37

What is course of the **Hypoglossel nerve CN XII**

Answer 37

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

Question 38

What are the **intrinsic mucles** of the tongue

Answer 38

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

Question 39

What is the course of the hypoglossle nerve- **CN XII**

Answer 39

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

Question 40

What are the muscle of the pharynx

Answer 40

* **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**

Question 41

What is the **Cricopharyngeus**

Answer 41

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

Question 42

What are the **longitudinal muscle of the pharynx**

Answer 42

* **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

Question 43

What is the **Paraphyrangeal spacev**

Answer 43

* 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

Question 44

What is the process of swallowing

Answer 44

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

Question 45

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

Answer 45