Neuroscience Anat (CN V and VII) Flashcards
RECALL:
State the sensory and motor functions of CN V
CN V - TRIGEMINAL N
- **somatosensory **= V1-V3 + anterior 2/3 of tongue (lingual N)
- somatomotor = V3 - muscles of mastication (masseter, temporalis, pterygoid) + 1st pharyngeal arch (anterior belly of digastric, mylohyoid, tensor tympani, tensor veli palatini)
RECALL:
State the sensory and motor functions of CN VII
CN VII - FACIAL N
- somatosensory = external ear
- special sensory = anterior 2/3 of tongue (chorda tympani)
- somatomotor = muscles of facial expression + 2nd pharyngeal arch (stapedius, stylohyoid, posterior belly of digastric)
- visceromotor (parasympathetic) = all facial glands except parotid gland (submandibular, sublingual, lacrimal)
State the cranial nerves that exit from
(1) midbrain
(2) pons
(3) medulla oblongata
(1) MIDBRAIN - CN III, IV
(2) PONS - CN V, VI, VII, VIII
(3) MEDULLA OBLONGATA - CN IX, X, XI, XII
RECALL:
State the CN that have parasympathetic functions. Name the presynaptic and postsynaptic neurons.
3,7,9, 10
CN III - oculomotor N
- parasympathetic supply = IOM (ciliary muscles, sphincter pupillae)
- presynaptic neuron = Edinger-Westphal Nc
- postsynaptic neuron = ciliary G
CN VII - facial N
- parasympathetic supply = submandibular, sublingual, lacrimal gland
- presynaptic neuron = salivatory Nc (submandibular + sublingual), lacrimal Nc (lacrimal gland)
- postsynaptic neuron = submandibular G (submandibular + sublingual), pterygopalatine Nc (lacrimal gland)
CN IX - glossopharyngeal N
- parasympathetic supply = parotid gland
- presynaptic neuron = salivatory Nc
- postsynaptic neuron = otic G
CN X - vagus N
- parasymaptheitc supply = heart, lungs, digestive system
- presynaptic neuron = dorsal motor nucleus of vagus
- postsynaptic neuron = various ganglia within/near organs
RECALL:
State the cranial nerves involved in taste (special sensory). State their pathways (involving any ganglia or nuclei).
CN VII, CN IX, CN X
CN VII - facial N
- supply = anterior 2/3 of tongue (chorda tympani)
- chorda tympani –> trigeminal ganglia –> nucleus of tractus solitarius
CN IX - glossopharyngeal N
- supply = posterior 1/3 of tongue
- posterior 1/3 of tongue –> glossopharyngeal ganglia –> nucleus of tractus solitarius
CN X - vagus N
- supply = epiglottis
- epiglottis –> vagal ganglia –> nucleus of tractus solitarius
CN V - TRIGEMINAL N
- State the somatosensory divisions of CN V
- State the foramen through which each divsion exits
- State the structures supplied by each division
CN V - TRIGEMINAL N
- Divisions = V1 (ophthalmic), V2 (maxillary), V3 (mandibular)
- Foramen: V1 (superior orbital fissure), V2 (foramen rotundum), V3 (foramen ovale)
- Supply of structures:
(V1) = forehead, scalp, orbit, eye, nose, anterior cranial fossa = vertex to nose
(V2) = maxilla, sinus, teeth, palate, nasal cavity, face and upper lips, pharynx, middle cranial fossa
(V3) = mandible, teeth, TMJ, parotid, oral cavity, cheek, tongue, scalp, chin, lower lip, middle cranial fossa
RECALL:
State the 3 types of trigeminal sensory nuclei. State their respective pathways.
State their respective functions.
State their locations in CNS.
3 TRIGEMINAL SENSORY NUCLEI:
1. spinal nucleus
2. principal (chief) sensory nucleus
3. mesencephalic nucleus
SPINAL NUCLEUS
- located in medulla and upper cervical cord
- function = pain and temperature
- trigeminal ganglion/sensory ganglia of 7,9,10 –> spinal nucleus of trigeminal –> decussate –> thalamus –> postcentral gyrus (sensory cortex)
PRINCIPAL (CHIEF) SENSORY NUCLEUS
- located in pons
- function = pressure and touch (discriminative)
- trigeminal ganglion –> principal sensory nucleus –> decussate –> thalamus –> postcentral gyrus (sensory cortex)
MESENCEPHALIC NUCLEUS
- located in midbrain
- function = proprioception
- mesencephalic nucleus of trigeminal –> brainstem –> decussate –> thalamus –> postcentral gyrus (sensory cortex)
RECALL: CN V - TRIGEMINAL N (somatomotor)
- State the muscles supplied
- State the LMN and UMN and pathway for motor supply
CN V - TRIGEMINAL N (somatomotor)
- Muscles supplied = muscles of mastication (temporalis, masseter, pterygoids) + 1st pharyngeal arch (anterior belly of digastric, mylohyoid, tensor tympani, tensor veli palatini)
- LMN = trigeminal motor nuclei
- UMN = (bilateral) precentral gyrus
- Pathway = bilateral UMN influence –> trigeminal motor nuclei –> muscles
RECALL:
State the difference between corticobulbar and corticospinal tract.
- Corticobulbartracts receive dual UMN supply
- Corticospinal tracts only receive contra-lateral UMN supply (with exception of CN7 and CN12)
State the pathway of corticospinal tract
- cerebral cortex (motor cortex)
- corona radiata
- internal capsule
- midbrain - crus cerebri
- medulla - pyramids
- (does not decussate - majority) lateral corticospinal tract
- (decussates - minority) anterior corticospinal tract
RECALL: CN VII - FACIAL N (sensory)
- State the sensory functions
- State the pathways involved
CN VII - FACIAL N (SENSORY)
- Somatosensory = external ear
- Special sensory = taste for anterior 2/3 of tongue (chorda tympani)
SOMATOSENSORY PATHWAY:
External ear –> Geniculate ganglion (1st order) –> spinal nucleus of trigeminal (V) (2nd order) –> thalamus –> sensory cortex
SPECIAL SENSORY (TASTE)
Chorda tympani –> Geniculate ganglion (1st order) –> nucleus of tractus solitarius (2nd order) –> thalamus –> sensory cortex
CN VII - FACIAL N (motor)
- State the motor functions and muscles involved
- State the UMN and LMM involved
- State any clinically significant pathologies and any differences.
CN VII - FACIAL N (motor)
- Somatomotor = muscles of facial expression + 2nd pharyngeal arch (stapedius, stylohyoid, posterior belly of digastric)
- Visceromotor = facial glands (submandibular, sublingual, lacrimal)
- UMN = bilateral UMN influence except for lower quarter of face which has contralateral influence only
- LMN = facial motor nucleus (at pontomedullary junction)
VISCEROMOTOR (ANS)
- submandibular and sublingual - (1st order N) = salivatory Nc - (2nd order N) = submandibular G
- lacrimal - (1st order N) = lacrimal Nc - (2nd order N) = pterygopalatine G
PATHOLOGY:
Bell’s palsy causes both upper quadrant and lower quadrant on same side of face to be paralysed (entire ipsilateral side of the LMN is paralysed)
State the course of CN V (and its divisions) and CN VII
CN V1 - superior orbital fissure - orbit
CN V2 - foramen rotundum - pterygopalatine fossa
CN V3 - foramen ovale - infratemporal fossa
CN VII - internal acoustic meatus - stylomastoid foramen
