introduction to cranial nerve, olfactory nerve, olfactory bulb, course of orlfactory nerve, termination in the cerebral cortex, functional component of cranial nerve

1. CRANIAL
NERVES
DR SANA YASEEN
ANATOMY DEPARTMENT
KIMS

2. INTRODUCTION
– There are 12 pair
of cranial nerves
– They may be
sensory, motor or
mix
I OLFACTORY Sensory
II OPTIC Sensory
III OCULOMOTOR Motor
IV TROCHLEAR Motor
V TRIGEMINAL Mix
VI ABDUCENT Motor
VII FACIAL Mix
VIII VESTIBULOCOCHLEAR Sensory
IX GLOSSOPHARYNGEAL Mix
X VAGUS Mix
XI ACCESSORY Motor
XII HYPOGLOSSAL Motor

3. Functional component
AFFRENT FIBERS EFFERENT FIBERS
General somatic afferent - gsa
Special somatic afferent - ssa
General visceral afferent - gva
Special visceral afferent - sva
General somatic efferent - gse
General visceral eeferent - gve
Special visceral efferent - sve

4. OLFACTORY
NERVE
I

5. OLFACTORY
NERVE
– Cell body of olfactory nerve are located
in olfactory mucous mambrane located
in the roof of nasal cavity, along nasal
septum, medial wall of superior nasal
conchae
– Apical surface of neurons posses
olfactory cilia bath by film of water
mucus. The cilia are stimulated by
molecules of odiferus gas dissolve,
inturn stimulating cell

6. – Basal surface of olfactory receptor
neurons give rises to central
processes collected in app. 20
olfactory nerves
– The bundle of nerve fibers psses
through tiny foramen in cribriform
plate of ethmoid bone and enters
into olfactory bulb.
– Olfactory bulb lies in orbital (inferior)
surface of frontal lobe of cerebral
hemisphere( anterior cranial fossa).

7. – Bulb is ovoid structure.Within the
olfactory bulb are bundles of nerve
fibers known as glomeruli; where
incoming receptor cell axons make
connections with the dendrites of
mitral relay neurons. Oter cells
include tufted cell, granular cells.
– Olfactory nerve fiber synapse with
dendrites of mitral cell also recieves
fibers from opposite side olfactory
bulb.
– The fibers arising from these mitral
cells makes up the OLFACTORY
TRACT.

9. – OLFACTORY TRACT. Is a narrow band of white
matter arising from the posterior end of the
olfactory bulb beneath inferior surface of frontal
lobe of brain.
– It consist of central axons of mitral tuft cells of bulb
and some fibers from opposite olfactory bulb.
– As olfactory tract rreaches anterior perforated
substance the tract divides in to
 Medial ollfactory strai
 Lateral olfactory strai
MEDIAL OLFACTORY STRAI:
- Medial olfactory strai crosses anterior commisure
to pass to the olfactory bulb of opposite side

10. LATERAL OLFACTORY STRAI:
- Carries axon to cerebral cortex
(area)
- PRIMARY OLFACTORY AREA:
- Periamaygdaloid
- Peripiriform cortex
- Lateral olfactory gyrus
- Anterior perforated substance
- Primary olfactory cortex sends
fibers to para hippocampal gyrus
and called ...
... SECONDARY OLFACTORY
CORTEX:
- brodmann’s area = 28

12. SUMMARY
– NAME: OLFACTORY NERVE
– NUMEROLOGOCALLY: CRANIAL NERVE - I
– FUNCTIONAL COMPONENT: SVA
– ORIGIN: OLFACTORY RECEPTOR NEURON IN NASAL
CAVITY
– ENDS: PRIMARY AND SECONDARY OLFACTORY
CORTICAL AREAS
– FUNCTION: CARRIES SENSE OF SMELL