Anatomy of the Upper GI Tract

Question 1

What are the 4 functions of the upper GI tract?

Answer 1

Mastication
Deglutition
Taste
Salivation

Question 2

What are the 4 structures involved in mastication?

Answer 2

Upper teeth of maxilla
Lower teeth of mandible
Tongue
Buccinator muscle (cheek muscle)

Question 3

What is the function of mastication?

Answer 3

Chops food increasing surface area which facilitates taste and beginning of digestion

Question 4

What are the components of the adult dentition?

Answer 4

4 quadrants, each containing:
2 incisors (1 & 2)
1 canine (3)
2 premolars (4 & 5)
3 molars (6, 7 & 8)0
(32 in total)

Question 5

what does the temporomandibular joint consist of?

Answer 5

Temporal bone has a mandibular fossa where head of condylar process of mandible sits

Question 6

what 4 muscles control the opening and closing of the TMJ?

What nerve supplies them?

Answer 6

Temporalis major = closes (over temples)
Masseter = closes (jaw)
Medial pterygoid = closes (vertical)
Lateral Pterygoid = opens (horizontal)
All supplied by CN V3 (mandibular division of the trigeminal nerve)

Question 7

what are the 2 cavities of the TMJ and what separates them?

Answer 7

superior cavity for translation
Inferior cavity for rotation
Separated by articular disc

Question 8

what is the function of the lateral pterygoid?

Answer 8

pulls the articular disc forward, increasing the size of the superior and inferior cavity cavity

Question 9

describe the course of CN V3

Answer 9

originates in the pons
travels through foramen ovale
travels to muscles of mastication and sensory area

Question 10

does the mandibular division of the trigeminal nerve (CN V3) contain both sensory and motor fibres?

Answer 10

yes

Question 11

why might you ask a patient about their dental health or if they have any loose or loose arts of teeth?

Answer 11

poses a choking hazard and aspiration risk as well as infection risk

Question 12

what is the position and function of the posterior 1/3rd of the tongue?

Answer 12

sits vertically in the oropharynx

involved in taste and general sensation (CNIX)

Question 13

what is the position and function of the anterior 2/3rds of the tongue?

Answer 13

sits horizontally in the oral cavity

involved in taste (CNVII) and general sensation (CNV3)

Question 14

what are the 4 types of papillae in the tongue and where are they?

Answer 14

Foliate = towards the back on the sides
Vallate = v shaped, at division between posterior/anterior
Fungiform (taste buds) = over mid tongue
Filiform = tip of tongue

Question 15

what is the route of the facial nerve?

Answer 15

arises from the pontomedullary junction
travels through the temporal bone via the internal acoustic meatus, then the stylomastoid foramen
Goes on to supply:
anterior 2/3rds of tongue
muscles of facial expression
glands in floor of mouth

Question 16

how does the facial nerve get to the tongue and mouth glands?

Answer 16

it splits in 2 and one half “piggy backs” on the lingual nerve while the other half goes to the muscles of facial expression

Question 17

what is contained in the superior half of the oral cavity and what nerve is responsible for its sensation?

Answer 17

gingiva (gums) of oral cavity and palates

innervated by CN V2

Question 18

what is contained in the inferior half of the oral cavity and what nerve is responsible for its sensation?

Answer 18

gingiva (gums) of oral cavity and floor of mouth

innervated ny CN V3

Question 19

how sensitive is the posterior wall of the oropharynx?

Answer 19

extremely

Question 20

what nerves are responsible for the sensory and motor parts of the gag reflex?

Answer 20

sensory = CN IX
Motor = CN IX and X

Question 21

what happens during the gag reflex?

Answer 21

the pharynx is constricted (closed off)