GI HARC 1

Question 1

Answer 1

Question 2

The Tongue

Answer 2

• Mobile, muscular organ
• Occupies floor of oral cavity
• Has very rich neurovascular supply

Question 3

Key functions of mouth

Answer 3

• Mastication
• Swallowing
• Taste
• Speech

Question 4

Structure Tongue

Answer 4

1) 8 muscles in a coat of oral mucosa

• Alter shape and position of tongue
• Protrusion/retraction and side-to-side movement

2) Has an oral part

• Anterior to terminal sulcus
• Approx. 2/3
• Horizontal

3) Has a pharyngeal part

• Posterior to terminal sulcus
• Approx. 1/3
• More vertical

Question 5

Answer 5

Question 6

Innervation of the Tongue

3 types of innervation:

Answer 6

1) General somatic efferent

• aka motor
• Innervation to muscles

2) General visceral afferent

• aka general sensory
• Tactile sensation; “touch”

3) Special visceral afferent

• Special sensory; taste

Question 7

Answer 7

Question 8

Answer 8

Question 9

What is Masticatory mucosa?

Answer 9

• Mucosa is thicker and contains keratinized epithelia more anteriorly
• Deals with greater dehydration and abrasion during mastication

Question 10

What are the mucosal projections?

Answer 10

• Vallate papillae
• Fungiform papillae
• Filiform papillae
• Foliate papillae

Have specialised mucosa with nerve endings for general sense and taste

Question 11

Answer 11

Question 12

Sensory Innervation to ANTERIOR 2/3 of Tongue

Answer 12

• General sensation • Lingual nerve • A branch of mandibular nerve (cn. V3 )
• Taste (special sensation) • Chorda tympani • A branch of facial nerve (cn. VII)

Question 13

Sensory Innervation to POSTERIOR 1/3 of Tongue

Answer 13

Question 14

Sensory Innervation to POSTERIOR 1/3 of Tongue

Answer 14

• General sensation • Glossopharyngeal nerve (cn. IX)
• Taste (special sensation) • Glossopharyngeal nerve (cn. IX)

Question 15

Functions of Saliva

Answer 15

Functions:

1. Lubricates food to assist with swallowing
2. Contains digestive enzymes and antimicrobial agents to resist periodontal infection
3. Moistens buccal mucosa – v. important for speech

Question 16

Saliva

Secretion (via ducts):

Answer 16

• Continuous at rest
• Mostly in response to drying out of oral/pharyngeal mucosa
• Rapid increase with mastication through autonomic innervation

Question 17

Salivary Glands

What are the exocrine glands?

Answer 17

Major (paired): Parotid glands, Submandibular glands, Sublingual glands Minor: Found throughout oral mu

Question 18

Answer 18

Question 19

Answer 19

Question 20

Is Salivatoin is autonomic or somatic

Answer 20

autonomic

Question 21

The Parotid Gland

Answer 21

Secretomotor supply:

• Originates in glossopharyngeal n.
• Synapses in otic ganglion
• Carried to gland in auriculotemporal n.

Question 22

Answer 22

Question 23

Submandibular Gland

Answer 23

Secretomotor supply:

• From chorda tympani (cn. VII)
• Carried in lingual n.
• Synapses in submandibular ganglion
• Synapse here is secretomotor only, not taste

Question 24

Answer 24

Question 25

Sublingual Gland:

Answer 25

Secretomotor supply: • From chorda tympani (cn. VII) - Carried in lingual n. • Synapses in submandibular ganglion - Synapse here is secretomotor only

Question 26

Answer 26

Question 27

Nerves Origin Parotid gland: Submandibular gland: Sublingual gland:

Answer 27

**Parotid gland:** Glossopharyngeal n. (cn. IX); otic ganglion **Submandibular gland:** Chorda tympani (cn. VII); submandibular ganglion **Sublingual gland:** Chorda tympani (cn. VII); submandibular ganglion

Question 28

The Facial Nerve Where does it pass through?

Answer 28

* Passing through the parotid gland * Does not supply it! * Important consideration for parotidectomy

Question 29

Synovial joint between:

Answer 29

* Temporal bone (mandibular fossa) * Mandible (condyle of mandible)

Question 30

• Unique pair of joints:

Answer 30

* Bilateral (left & right) * Functions as a single unit * Symmetrical opening important for incising

Question 31

Answer 31

Question 32

Movement at the The Temporomandibular Joint

Answer 32

* TMJ is divided into 2 parts (by an articular disc) * Upper joint compartment • Lower joint compartment * Allows for 2 movements in the sagittal plane, simultaneously - Sliding back and forth (protrusion & retraction) - Hinge/rotation (elevation & depression) • Also lateral movement

Question 33

Answer 33

Question 34

Answer 34

Question 35

What do the letters stand for?

Answer 35

M = mandibular fossa AT = articular tubercle H = head of mandible N = neck of mandible

Question 36

What are the muscles of mastication?

Answer 36

* 4 muscles produce movement of the mandible at TMJ * Temporalis * Masseter * Medial pterygoid * Lateral pterygoid

Question 37

Muscles of Mastication What are they innervated by?

Answer 37

* All innervated by Cn. V3 * Mandibular division of trigeminal nerve * Because all derived from 1st pharyngeal arch

Question 38

What is the function of temporalis?

Answer 38

* Anterior fibres are vertical - Elevation! * Posterior fibres are horizontal - Retraction!

Question 39

What is the function of the Masseter?

Answer 39

* Deep fibres are vertical - Elevation! * Superficial fibres are oblique - Elevation… and protraction!

Question 40

Name the coloured muscles

Answer 40

* Medial pterygoid - Elevates mandible * Lateral pterygoid - Pulls mandible anteriorly at TMJ – important for allowing mouth to open