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Nasal and oral cavities, tongue, taste, olfaction,

salivary glands

• Describe the central pathways of olfaction (CN I) andtaste (VII, IX, X)

• Describe the anatomy of the tongue, including motorand sensory (general and taste) innervation, bloodsupply, and lymphatic drainage

• Identify the salivary glands and components of thepalate, nasal and oral cavities, and paranasal air sinuses,

and summarise their innervation and blood supply• Summarise functions of CN I, V, VII, IX, X, XII related

to the above regions

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Dissection Lab availability

during study week and exams

• Open

 –  5 June – 9 June, 9am-5pm

 –  12-13 June, 9am-5pm

•

Written 14 June, 9-11am• Prac 16 June, 1pm – 5pm (4 groups, 1 hour each)

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Suprahyoid muscles

• Digastric, anterior (V3) &

posterior bellies (VII)

• Stylohyoid (VII)

• Mylohyoid - floor of mouth (V3)

• Geniohyoid (C1)

• Actions: raise hyoid bone and floor

of mouth during swallowing,

stabilise hyoid, lower mandible

(open mouth)

Netter 47

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Teeth• Joints: gomphoses (fibrous peg in socket joint)

between teeth and superior/inferior alveolar

processes of maxilla/mandible

•4 x (2 incisors, 1 canine/cuspid, 2premolars/bicuspids, 3 molars) = 32 permanent

• Crown, root

• Root canal with nerves, vessels

 –  Mandibular teeth – inferior alveolar n (V3)

 –  Maxillary teeth – superior alveolar nn (V2)

 –  Vessels for both from maxillary artery

Netter 50, http://www.ada.org/public/topics/permanent_number.asp

R L

Upper

Lower

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Parotid salivary gland

• Key n/a/v relations: facial n,

retromandibular v, external carotid a,superficial temporal aa/vv,

auriculotemporal n

• Parotid duct pierces buccinator, opens

opposite 2

nd

upper molar

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          N                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    t                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          t                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    e                    

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           r                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               9                                                                                                                                                                                                                                               ,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 4                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         5                                                                                                                                                                                                                                                    ,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              5                    

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             4

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Parasympathetic innervation of salivary glands

• Parotid: inferior salivatory nucleus, glossopharyngeal n (IX), oticganglion (synapse), postganglionics via auriculotemporal n (of V3)

• Submandibular and sublingual: superior salivatory nucleus, facialn (VII), chorda tympani to lingual nerve (of V3), submandibular

ganglion (synapse)

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          N                      

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    t                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         t         

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               r                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             2

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          7                                                                                                                                                                                                                                                   ,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             2                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           8                    

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Tongue muscles• Intrinsic: longitudinal, transverse,

vertical (change shape of tongue)

• Extrinsic: genioglossus (protrudes),

hyoglossus (lowers and retracts),styloglossus and palatoglossus (elevate

and retract)

Netter 54, 53

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Innervation of tongue muscles: hypoglossal nerve (CN XII)

• All muscles of tongue by XII except palatoglossus (X)

•

Lower motor neurons in hypoglossal nucleus in medulla• Exit brainstem at preolivary sulcus, cranial cavity at hypoglossal

canal

   N  e   t   t  e  r   1   0   8

   F   i  x   2   3

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UMN control over hypoglossal nucleus

LMNs: Corticobulbar tract

• Cell bodies in primary motor cortex and

nearby areas

• Fibres travel through internal capsule,

cerebral peduncle of midbrain, basal pons

• UMNs supply LMNs bilaterally

• Unilateral UMN lesion - usually no observable effect on

tongue

• Unilateral LMN lesion - ipsilateral tongue paralysed,

atrophies with time

 –  Stick tongue out – deviates towards side of lesion

(paralysis of genioglossus)

   N  e   t   t  e  r   5   3 ,

   N  o   l   t  e   4   4   7

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Gustatory sensation

• “Taste” includes smell, gustatory sense,

general sensation (touch, temperature)

• Dorsum of tongue contains papilla, most

without taste buds (filiform), some with

(fungiform, foliate, vallate)

•

Taste buds detect salty, sweet, sour,bitter, umami (glutamate)

   N  e   t   t  e  r   5   3 ,

   W   h  e  a   t  e  r   3   1   6

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Taste pathways

• Anterior 2/3 tongue: VII,

geniculate ganglion (1o

)• Posterior 1/3 tongue: IX,

petrosal ganglion (1o)

• Epiglottis, pharynx: X,nodose ganglion (1o)

• Nucleus of solitary tract (2o)

• Pontine taste area (3o)

• Thalamus (VPM) (4o)

• Insula, postcentral gyrus (5o)

• Limbic system, hypothalamus,orbital cortex of frontal lobe

Netter 129 Fix 23

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General sensation from tongue

• Anterior 2/3 of tongue: V3

• Posterior 1/3 of tongue: IX

• Trigeminal, petrosal ganglia(1o)

• Same pathway as generalsensation from face:

• Descending (pain,temp), main(touch) nuclei of V (2o)

• (cross) trigeminothalamic tract

• VPM thalamus (3o)

• Postcentral gyrus of cortex (4o)

Haines 230; Drake 8.248 

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Glossopharyngeal n (IX), hypoglossal nerve (XII),

and lingual n (V3 branch)

• Lingual n: deep to mandible

• Hypoglossal n: superficial toexternal and internal carotid

aa and hyoglossus, superior to

mylohyoid – motor to tongue

• Glossopharyngeal n: close tostylopharyngeus (supplies it),

between external and internal

carotid arteries

 – 

Sensory (general and taste) toposterior 1/3 of tongue

 –  Sensory to much of pharynx

 –  Supplies carotid sinus and body

 –  Parasympathetic to parotid

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          N                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    t                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          t         

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               r

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            6                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             5                    

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Blood supply of tongue

• Lingual artery from external carotid artery

 –  branches include dorsal lingual, sublingual, deep lingual aa

• Lingual veins (with lingual a and XII) drain to internal jugular

vein (usually join facial vein first)

Netter 53 

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Lymphatic drainage

of tongue

• Important in spread of cancer

• Anterior tongue: to

submental, submandibular

nodes and then to deepcervical nodes (including

 juguloomohyoid node)

• Posterior tongue: to deep

cervical nodes (including jugulodigastric node)

• Central part of tongue -

bilateral drainage

Netter 66 

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External nose

• Bony margins: nasal bones, maxillae

• Major cartilages:

 –  lateral nasal cartilage

 –  greater alar cartilage - lateral crus and

medial crus

Netter 31

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Nasal septum

• Separates nasal cavity on midline

•Bony: vomer, perpendicular plate of ethmoid

• Cartilaginous: septal cartilage, medial crura of greater alarcartilages

                                                                                                                                                                                                                                      N                                                                                                                                                                       e                                                                                                                                                                                                                              t                                                                                                                                                                                                                          t                                                                                                                                                                    e                                                                                                                                                                        r                                                                                                                                                                                                                                          3                                                                                                                                                                                                                                              4                                                     ,                                                            

                                                                                                                                                                                                                                      W                                                                                                                                                                      e                                                                                                                                                                                                                                                i                                                                                                                                                                  r                                                                                                                                                                                                                                          9                                                                                                                                                                      e      

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Paranasal air sinuses

• Maxillary sinus

 –  Opens into semilunar hiatus of middle meatus

• Ethmoid air cells

 –  open into middle and superior meatuses

• (Note: nasolacrimal duct opens into

inferior meatus)

   N  e   t

   t  e  r   3   2 ,

   W  e   i  r   8   d

 ,   D  r  a   k  e   8 .   2

   1   8

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Palate

• Separates nasal and oral cavities, and can

separate naso- and oro-pharynx

• Hard palate: maxilla and palatine bones

• Soft palate: posterior to hard palate

                                                                                                                                                                                                                                      N                                                                                                                                                                       e                                                                                                                                                                                                                              t  

                                                                                                                                                                                                                        t                                                                                                                                                                    e                                                                                                                                                                        r                                                                                                                                                                                                                                     5                                                         ,                                                                                                                                                                                                                                                                                                  W                                                                                                                                                                      e                                                                                                                                                                                                                                                i                                                                                                                                                                  r

                                                                                                                                                                                                                                         1                                                                                                                                                                                                                                         8                                                                                                                                                                                                                                           b     

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Muscles of soft palate• Levator veli palatini, tensor veli palatini,

palatoglossus, palatopharyngeus, musculus uvulae

• Elevated during swallowing, depressed during

chewing• Innervated by vagus n (X), with LMNs in nucleus

ambiguus (Exception: tensor veli palatini by V3)

• Unilateral LMN or CN X lesion: uvula deviates awayfrom side of lesion, soft palate droops on affected side

                                                                                                                                                                                                                                      N                                                                                                                                                                       e                                                                                                                                                                                                                              t                                                                                                                                                                                                                           t                                                                                                                                                                    e                                                                                                                                                                        r

                                                                                                                                                                                                                                         4                                                                                                                                                                                                                                        6                                                         ,                                                                                                                                                                                                                                                                                                 5                                                                                                                                                                                                                                              8                                                          ,                                                                                                                                                                                                                                                                                                  D                                                                                                                                                                  r                                                                                                                                                                   a

                                                                                                                                                                                                                                     k                                                                                                                                                                  e                                                                                                                                                                                                                                               8                                                          .                                                                                                                                                                                                                                              2                                                                                                                                                                                                                                     5                                                                                                                                                                                                                                          7                                                         ,                                                                                                                                                                                                                                                                                                     8                                                          .                                                                                                                                                                                                                                              2

                                                                                                                                                                                                                                     5                                                                                                                                                                                                                                              8      

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General sensory innervation and blood supply

of nasal cavity and palate• Nerves: Mostly branches of maxillary division of trigeminal n (V2)

 – 

Anteriorly, branches of ophthalmic division of trigeminal n (V1)• Arteries: Mostly from maxillary artery (from external carotid a)

 –  Anteriorly and superiorly from ophthalmic artery (from internal carotid a)

 –  Near vestibule from facial artery (from external carotid a)

                                                                                                                                                                                                                                      N                                                                                                                                                                       e                                                                                                                                                                                                                              t                                                                                                                                                                                                                          t                                                                                                                                                                     e                                                                                                                                                                        r

                                                                                                                                                                                                                                          3                                                                                                                                                                                                                                             6                                                         ,                                                                                                                                                                                                                                                                                                       3     

                                                                                                                                                                                                                                     7     

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Parasympathetic innervation of nasal cavity and palate

• Supplies mucus glands

• Superior salivatory nucleus

• Facial nerve (CN VII)

• Pterygopalatine ganglion (synapse), postganglionic fibres viabranches of maxillary nerve (V2) (also to lacrimal gland)

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          N                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    t                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         t         

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           e                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               r                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             1                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             2

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          7                   

Olf i ( ll)

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Olfaction (smell)• Olfactory epithelium in superior nasal cavity-lateral wall&septum

• Receptor cells are bipolar neurons - dendrite has cilia with G-

protein coupled odorant receptors (about 1000 different odorantreceptors, each neuron expresses only one type of receptor)

• Olfactory axons pass through cribriform plate of ethmoid bone to

synapse in olfactory bulb

•

Head trauma may cause anosmia - loss of smell, and reduced taste• Olfactory neurons replaced throughout life, and axons must grow

to correct targets in olfactory bulb (CNS)Netter 36, 113

Olf ti ( ll)

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Olfaction (smell)

• Olfactory bulb projects ipsilaterally via olfactory tract to primary

olfactory cortex (piriform cortex, anterior perforated substance)

• Only sensory modality to reach cerebral cortex without firstsynapsing in thalamus

• From primary olfactory cortex, to hypothalamus, amygdala,

limbic system, DM thalamus, other cerebral cortex including

insula

Netter 113, Nolte 13.15