Central Nervous System for 1st year M.B.B.Students

1. CRANIAL NERVE NUCLEI
Dr Anita Rahul Gune
Associate Professor, Anatomy
D.Y.Patil Medical College, Kolhapur

2. Histogenesis of Neural tube
Formation of Layers
Neuroepithelial layer –single layer
then proliferates to form matrix
that differentiates into mantle and
marginal layer.
Later differentiate into ependymal
cells.

3. Mantle Layer – cells of mantle layer
divide to rise to neurons This layer later
forms grey matter of central nervous
system.
Marginal Layer – nerve fibres which
are myelinated, makes them appear
white, White matter of the Central
Nervous system.
In Cerebrum and Cerebellum
cells migrate and appear in Marginal
layer (Cortical grey matter)

4. Mantle layer :
Ventral laminae or Basal plates
Dorsal laminae or Alar plates
Separated by Sulcus limitans

5. Basal plates
Somatic Efferent (SE)
Special Visceral Efferent (SVE)
General Visceral Efferent (GVE)
Alar Plate
General Visceral Afferent GVA
Special Visceral Afferent SVA
General Somatic Afferent GSA
Special Somatic Afferent SSA

6. Somatic efferents: voluntary muscles of
somatic origin III, IV,VI,XII
Special visceral efferent
Branchial efferent
V,VII, Nucleus Ambigus
(IX,X,XI)
General Visceral Efferent
Preganglionic cranial
Parasympathetic outflow
Edinger Westphal nucleus(III),
Superior salivatory (VII),
Inferior salivatory (IX),
Dorsal Nucleus of vagus (X)

7. Special somatic afferents:
vision, hearing, equilibrium
Special visceral Afferents:
Taste ( Nucleus of solitary tract)
VII,IX,X
General Visceral Afferent
Hunger, thirst
Dorsal nucleus of vagus
General Somatic Afferent
Trigeminal nucleus

8. SE
SVE
GVE
GSA
GVA
SSA
Efferents
Afferents
SVA

9. I Olfactory (sensory)
II Optic (sensory)
III Oculomotor (motor)
IV Trochelar (motor)
V Trigerminal (mixed)
VI Abducent (motor)
VII Facial (mixed)
VIII Vestibulocochlear
( sensory)
IX Glossopharyngeal
(mixed)
X Vagus (mixed)
XI Accessory (motor)
XII Hypoglossal (Motor)

10. I Olfactory (sensory) SSA
Smell
II Optic (sensory) SSA
Vision
VIII Vestibulocochlear ( sensory) SSA
Hearing
Junction of pons and medulla.

11. III Oculomotor (motor) SE (movements of eyeball) ,
GVE (contraction of pupil ,accomodation),
GSA (Trigerminal nucleus)
Midbrain at level of superior colliculus
IV Trochelar (motor) SE (movements of eyeball)
GSA (Trigerminal nucleus)
Midbrain at level of Inferior colliculus
VI Abducent (motor) SE (movements of eyeball)
GSA(Trigerminal nucleus)
Lower Pons
XII Hypoglossal (Motor) SE (movements of tongue),
GSA(Trigerminal nucleus)
Medulla
XI Accessory (motor) SVE(Sternocleidomastoid and Trapezius. Motor to
muscles of soft palate and Pharynx (distributed via vagus)
Medulla and Spinal cord

12. V Trigerminal (mixed) SVE (Movements of mandible) ,
GSA (Mesencephalic ,Main ,Spinal nucleus)
VII Facial (mixed) SVE ( Muscles of Facial expression) ,
GVE (superior salivatory nucleus – submandibular, sublingual)
Lacrimatory nucleus – Lacrimal glands, nasal glands),
SVA (taste from anterior 2/3 of tongue),
GSA(Trigerminal nucleus)
IX Glossopharyngeal (mixed) SVE (elevation of pharynx),
GVE (Inferior salivatory nucleus – Partoid),
SVA (taste from posterior 1/3 of tongue) .
X Vagus (mixed) SVE(movements of larynx ,palate and pharynx)
GVE (secremotor to gut ,bronchial tree)
GVA (sensation from viscera) ,
SVA (taste from posteriormost of tongue, epiglottis) ,
GSA (Trigerminal nucleus) SVE Nucleus Ambigus 9,10,11
GVE Dorsal Nucleus of Vagus
GVA Dorsal Nucleus of Vagus
SVA Nucleus of Solitary Tract 7,9,10

15. I Olfactory
Special somatic afferent SSA
Cells of origin Olfactory receptor cells in nasal mucosa
Exit from skull Foramina of cribriform plate
Function Olfaction
II Optic
Special somatic afferent SSA
Cells of origin Ganglion cells of retina
Exit from skull Optic canal
Function Vision

16. III Oculomotor SE,GVE
Somatic efferent SE
Cells of origin Oculomotor nucleus
Motor to medial rectus, inferior rectus, superior rectus, inferior
oblique, levator palpebrae superioris
General visceral efferent GVE
Cells of origin Edinger–Westphal nucleus
Parasympathetic to sphincter pupillae and ciliary muscles, via
ciliary ganglion, mediating pupillary constriction and
accommodation
Superior orbital fissure

17. IV Trochlear
Somatic efferent SE
Cells of origin Trochlear nucleus
Superior orbital fissure
Motor to superior oblique

18. V Trigerminal GSA,SVE
Ophthalmic (Vi)
General somatic afferent GSA
Cells of origin Trigeminal (semilunar) ganglion
Superior orbital fissure
Sensation from forehead, scalp, eyelids, nose and eye, including
conjunctiva
Maxillary (Vii)
General somatic afferent GSA
Cells of origin Trigeminal (semilunar) ganglion
Foramen rotundum
Sensation from mid-face, lower eyelid, nasal cavity and paranasal
sinuses, upper lip, maxillary teeth and palate

19. Mandibular (Viii)
General somatic afferent GSA
Cells of origin Trigeminal (semilunar) ganglion
Sensation from lower face and scalp, tongue and floor of mouth, mandibular
teeth and part of external ear
Mesencephalic part of trigeminal sensory nucleus
Proprioception from muscles of mastication, temporomandibular joint
(special visceral) Branchial efferent SVE
Cells of origin Trigeminal motor nucleus
Motor to muscles of mastication(temporalis, masseter, medial and lateral
pterygoids), tensor tympani, tensor veli palatine, anterior belly of digastric,
mylohyoid.
Foramen ovale

20. VI Abducent
Somatic efferent SE
Cells of origin Abducent nucleus
Superior orbital fissure
Motor to lateral rectus

21. VII Facial GSA,SVA,GVE,SVE
General somatic afferent GSA
Cells of origin Geniculate ganglion
Sensation from part of tympanic membrane, external acoustic
meatus and skin behind pinna. Proprioception from facial muscles
Special visceral afferent SVA
Cells of origin Geniculate ganglion
Taste from anterior two-thirds of tongue

23. VII Facial
General visceral efferent GVE
Cells of origin Superior salivatory nucleus
Parasympathetic to lacrimal gland and mucous membrane of nasal
and oral cavities (via pterygopalatine ganglion) and submandibular
and sublingual salivary glands (via submandibular ganglion) causing
secretion and vasodilatation
Branchial (special visceral) efferent SVE
Cells of origin Facial nucleus
Motor to muscles of facial expression, stapedius, posterior belly of
digastric and stylohyoid
Internal acoustic meatus

25. VIII Vestibulocochlear
Vestibular division Special somatic
afferent SSA
Cells of origin Vestibular ganglion To
vestibular nuclei
Sensations of equilibrium and
motion
Cochlear division Special somatic
afferent SSA
Cells of origin Spiral ganglion To
cochlear nuclei
Hearing
Internal acoustic meatus

26. IX Glossopharyngeal GSA,GVA,SVA,GVE,SVE
General somatic afferent GSA
Cell of origin Glossopharyngeal ganglia To trigeminal sensory nucleus
General sensation from posterior one-third of tongue, oropharynx and middle ear
General Visceral afferent GVA
Cells of origin Glossopharyngeal ganglia
Sensory from carotid body (chemoreceptors) and carotid sinus (baroreceptors)
Special visceral afferent SVA
Cells of origin Glossopharyngeal ganglia To nucleus solitarius
Taste from posterior one-third of tongue
General visceral efferent GVE
Cells of origin Inferior salivatory nucleus
Parasympathetic to parotid salivary gland (via otic ganglion), causing secretion and
vasodilatation
Branchial (special visceral) efferent SVE
Cells of origin Nucleus Ambigus
Motor to stylopharyngeus
Jugular foramen

28. X Vagus GSA,GVA,SVA,GVE,SVE
General somatic afferent GSA
Superior (jugular) ganglion To trigeminal sensory nucleus
General sensation from pharynx, larynx, trachea, oesophagus, part of auricle
and external auditory meatus
General visceral afferent GVA
Inferior (nodose) ganglion
Sensory from thoracic and abdominal viscera
Sensory from aortic arch (baroreceptors) and aortic bodies (chemoreceptors)
General visceral efferent GVE
Cells of origin Dorsal motor nucleus of vagus
Parasympathetic to glands and smooth muscle in the pharynx, larynx; thoracic
and abdominal viscera
Branchial (special visceral) efferent SVE
Cells of origin Nucleus Ambigus
Motor to pharyngeal, external laryngeal and oesophageal striated muscles
Jugular foramen

30. XI Accessory SVE
Cranial root Branchial (special visceral)
efferent SVE
Cells of origin Nucleus Ambigus
Motor to muscles of soft palate and
intrinsic muscles of Pharynx (distributed
via vagus)
Spinal root Branchial (special visceral)
efferent SVE
Motor to sternocleidomastoid and
Trapezius
Jugular foramen

31. XII Hypoglossal SE
Somatic efferent
Motor to all intrinsic and
extrinsic muscles of the
tongue, except
Palatoglossus
Hypoglossal canal

32. Applied Anatomy
• Lesion of Facial nerve- Supra-nuclear or peripheral
• Supra-nuclear- UMN loss of movements of contralateral side, but
upper facial muscles escape as bilateral control of motor cortex
for these
• Nuclear- lesion of pons facial nucleus along with Abducent, also
corticospinal tract-Millard Gulbar Syndrome
• Infra-nuclear paralysis
• Bell’s palsy

33. Infra-nuclear paralysis
• Lesions in the internal acoustic meatus-
Bell’s palsy
• Genu (external) produces diminished
lacrimation , reduced taste sensation,
hyperacusis, Bell’s palsy on affected side
• Below stylo-mastoid foramen-Bell’s palsy-
causes
• Sudden exposure to cold
• Middle ear infections
• Tumours of middle ear, Partoid
• Partial or complete recovery in 2 to 8
weeks

34. Bell’s Palsy• Face asymmetrical
• Transverse wrinkles of forehead disappear
• Eyebrow drops
• Palpebral fissure is wider
• Corneal reflex is disturbed- corneal ulcers and
blindness
• Ectropion of lower lid and epiphora
• Nasolabial fold disappears
• Ala nasi does not move
• Tip of nose is deviated to the sound side
• Angle of mouth remains motionless
• Food accumulates in vestibule
• Whistling not possible