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BIOL 4260
Human Evolutionary Anatomy
Lecture 18: Cranial Nerves
Lecture 2: Fossil Record
Somatic vs. Autonomic Nervous Systems
•  Autonomic nervous system
–  Axons innervate the visceral organs
–  Afferent pathways originate in the
visceral receptors
•  Somatic nervous system
–  Axons innervate the skeletal
muscles
–  Afferent pathways originate in the
skeletal muscles
Autonomic Nervous System (ANS)
AUTONOMIC NERVOUS SYSTEM
•  Outside of our
conscious awareness
•  Regulates body
temperature
•  Coordinates
cardiovascular,
respiratory, digestive,
excretory, and
reproductive functions
THORACOLUMBAR DIVISION
(sympathetic
division of ANS)
CRANIOSACRAL DIVISION
(parasympathetic
division of ANS)
Cranial nerves
(N III, N VII, N IX,
and N X)
T1
T2
T3
T4
T5
Thoracic
nerves
T6
T7
T8
AUTONOMIC NERVOUS SYSTEM
Consists of 2 divisions
SYMPATHETIC
(thoracolumbar)
DIVISION
PARASYMPATHETIC
(craniosacral)
DIVISION
Preganglionic
neurons in
lateral gray horns of
spinal segments T1–L2
Preganglionic
neurons in brain
stem and in lateral
portion of anterior
gray horns of S2–S4
Send preganglionic
fibers to
Ganglia near
spinal cord
Preganglionic fibers
release ACh (excitatory),
stimulating
ganglionic neurons
Ganglia in or
near target organs
Preganglionic fibers
release ACh (excitatory),
stimulating
ganglionic neurons
Which send postganglionic
fibers to
Target organs
Target organs
Most postganglionic
fibers release NE at
neuroeffector junctions
All postganglionic fibers
release ACh at
neuroeffector junctions
“Fight or flight”
response
“Rest and repose”
response
Functional components of the ANS
The Parasympathetic Division
• Functions:
–  Pupil constriction
–  Secretion of digestive enzymes from digestive
glands
–  Increased smooth muscle activity of the
digestive system
–  Stimulation and coordination of defecation
–  Contraction of the urinary bladder
–  Constriction of respiratory passages
–  Reduced heart rate
–  Sexual arousal
Pterygopalatine ganglion
N III
Lacrimal gland
Eye
Ciliary ganglion
PONS
N VII
N IX
Salivary glands
Submandibular
ganglion
Otic ganglion
N X (Vagus)
Heart
Lungs
Autonomic plexuses
(see Figure 17.9)
Liver and
gallbladder
Stomach
Spleen
Pancreas
Large intestine
Pelvic
nerves
Small intestine
Rectum
Spinal
cord
S2
Kidney
S3
S4
KEY
Preganglionic neurons
Ganglionic neurons
Uterus
Ovary
Penis
Scrotum
Urinary bladder
The Cranial Nerves
•  There are 12 pairs of cranial nerves
– These nerves innervate the periphery emerging
from the brain (not the spinal cord)
– These nerves are on the ventrolateral surface of
the brain
– They are numbered beginning at the anterior
aspect of the brain
– They are numbered CN I to CN XII
The Cranial Nerves
Figure 16.22b Origins of the Cranial Nerves
Olfactory bulb, termination
of olfactory nerve (N I)
Olfactory tract
Optic chiasm
Optic nerve (N II)
Infundibulum
Oculomotor nerve (N III)
Trochlear nerve (N IV)
Trigeminal nerve (N V)
Abducens nerve (N VI)
Facial nerve (N VII)
Vestibulocochlear
nerve (N VIII)
Glossopharyngeal
nerve (N IX)
Vagus nerve (N X)
Hypoglossal nerve (N XII)
Accessory nerve (N XI)
Diagrammatic inferior view of the human
brain. Compare view with part (a).
Olfactory bulb, termination
of olfactory nerve (N I)
Olfactory tract
Mamillary
body
Optic chiasm
Optic nerve (N II)
Basilar
artery
Infundibulum
Pons
Oculomotor nerve (N III)
Trochlear nerve (N IV)
Trigeminal nerve (N V)
Abducens nerve (N VI)
Facial nerve (N VII)
Vestibulocochlear
nerve (N VIII)
Glossopharyngeal
nerve (N IX)
Vertebral
artery
Vagus nerve (N X)
Cerebellum
Hypoglossal nerve (N XII)
Medulla oblongata
Accessory nerve (N XI)
Spinal cord
The inferior surface of the brain as it appears on
gross dissection. The roots of the cranial nerves
are clearly visible.
The Cranial Nerves
•  CN I: The Olfactory Nerve
– Function: sensory (smell)
– Origin: olfactory epithelium
– Foramen: olfactory foramina
– Destination: olfactory bulbs
Left olfactory bulb
(termination of
olfactory nerve)
Olfactory tract
(to olfactory cortex
of cerebrum)
OLFACTORY
NERVE (N I)
Cribriform plate
of ethmoid
Olfactory epithelium
Olfactory
nerve fibers
Figure 18.6a The Olfactory Organs
Olfactory
bulb
Olfactory nerve
fibers (N I)
Olfactory
tract
Cribriform plate
of ethmoid
Olfactory
epithelium
The distribution of the olfactory receptors
on the left side of the nasal septum is
shown by the shading.
The Cranial Nerves
•  CN II: The Optic Nerve
– Function: sensory (vision)
– Origin: retina
– Foramen: optic canal
– Destination: diencephalon, then to occipital
lobe
Eye
Olfactory bulb
Olfactory tract
OPTIC NERVE
(N II)
Optic chiasm
Pituitary
gland
Optic tract
Mesencephalon
(cut)
Lateral
geniculate
nucleus
(in thalamus)
Optic
projection
fibers
Visual cortex
(in occipital lobes)
The Cranial Nerves
•  CN III: The Oculomotor Nerve
– Function: controls extra-ocular eye muscles
•  Motor function
•  Superior, inferior, and medial rectus
•  Inferior oblique
•  Levator palpebrae superioris
– Origin: mesencephalon
– Foramen: superior orbital fissure
– Destination: extra-ocular eye muscles
Superior
oblique
muscle
Superior
rectus
muscle
OPTIC
NERVE (N II)
Optic
chiasm
OCULOMOTOR
NERVE (N III)
TROCHLEAR
NERVE (N IV)
Trochlea
Levator
palpebrae
superioris
muscle
Trigeminal
nerve (N V), cut
Inferior
oblique
muscle
Vestibulocochlear
nerve (N VIII), cut
Inferior
rectus
muscle
Ciliary
ganglion
Medial
rectus
muscle
Facial nerve
(N VII), cut
Lateral
rectus
muscle
(cut)
ABDUCENS
NERVE (N VI)
The Cranial Nerves
•  CN IV: The Trochlear Nerve
– Function: controls extra-ocular eye muscles
•  Motor function
•  Superior oblique
– Origin: mesencephalon
– Foramen: superior orbital fissure
– Destination: extra-ocular eye muscles
Superior
oblique
muscle
Superior
rectus
muscle
OPTIC
NERVE (N II)
Optic
chiasm
OCULOMOTOR
NERVE (N III)
TROCHLEAR
NERVE (N IV)
Trochlea
Levator
palpebrae
superioris
muscle
Trigeminal
nerve (N V), cut
Inferior
oblique
muscle
Vestibulocochlear
nerve (N VIII), cut
Inferior
rectus
muscle
Ciliary
ganglion
Medial
rectus
muscle
Facial nerve
(N VII), cut
Lateral
rectus
muscle
(cut)
ABDUCENS
NERVE (N VI)
The Cranial Nerves
•  CN V: The Trigeminal Nerve
– Function:
•  Mixed (sensory and motor) function
•  Ophthalmic: sensations from the forehead, eyelids, and
nose
•  Maxillary: sensations from lower eyelid, upper lip, and
cheek
•  Mandibular: controls mastication
– Origin: ophthalmic, maxillary, and mandibular nerves
The Cranial Nerves
•  CN V: The Trigeminal Nerve (continued)
– Foramen:
•  Ophthalmic: superior orbital fissure
•  Maxillary: foramen rotundum
•  Mandibular: foramen ovale
– Destination:
•  Ophthalmic and maxillary: Pons
•  Mandibular: mandibular muscles
Superior
orbital
fissure
Ophthalmic
branch
Semilunar
ganglion
Supraorbital
nerves
Ciliary ganglion
Foramen
rotundum
Infra-orbital
nerve
Pons
TRIGEMINAL
NERVE (N V)
Maxillary
branch
Foramen ovale
Lingual nerve
Submandibular ganglion
Mental nerve
Otic ganglion
Mandibular branch
Pterygopalatine
ganglion
The Cranial Nerves
•  CN VI: The Abducens Nerve
– Function: controls eye movements
•  Motor function
– Origin: pons
– Foramen: superior orbital fissure
– Destination: innervates the lateral rectus eye
muscle
Superior
oblique
muscle
Superior
rectus
muscle
OPTIC
NERVE (N II)
Optic
chiasm
OCULOMOTOR
NERVE (N III)
TROCHLEAR
NERVE (N IV)
Trochlea
Levator
palpebrae
superioris
muscle
Trigeminal
nerve (N V), cut
Inferior
oblique
muscle
Vestibulocochlear
nerve (N VIII), cut
Inferior
rectus
muscle
Ciliary
ganglion
Medial
rectus
muscle
Facial nerve
(N VII), cut
Lateral
rectus
muscle
(cut)
ABDUCENS
NERVE (N VI)
The Cranial Nerves
•  CN VII: The Facial Nerve
– Function: Mixed (sensory and motor)
•  Sensory: sensations from the face / taste
•  Motor: controls muscles of the face
– Origin:
•  Sensory: taste buds
•  Motor: pons
– Foramen: internal acoustic meatus
– Destination:
•  Sensory: pons
•  Motor: muscles of the face
Pterygopalatine
ganglion
Greater
petrosal
nerve
Geniculate
ganglion
FACIAL
NERVE (N VII)
Temporal
branch
Pons
Zygomatic
branches
Posterior auricular
branch
Stylomastoid
foramen
Buccal
branch
Chorda tympani nerve
(with mandibular
branch of N V)
Mandibular
branch
Lingual branch
(with lingual nerve
of N V)
Cervical
branch
Origin and branches of the facial
nerve
Submandibular
ganglion
The Cranial Nerves
•  CN VIII: The Vestibulocochlear Nerve
– Function:
•  Sensory: balance and hearing
– Origin: receptors of the vestibule and cochlea
– Foramen: internal acoustic meatus
– Destination: pons
Tympanic
cavity
(middle ear)
Semicircular
canals
Vestibular
branch
(N VIII)
Facial
nerve
(N VII), cut
Internal
acoustic
canal
VESTIBULOCOCHLEAR
NERVE (N VIII)
NV
Pons
N VI
N VII
Medulla
oblongata
Tympanic
membrane
Auditory
tube
Cochlea
Cochlear
branch (N VIII)
N IX
N XII
NX
N XI
The Cranial Nerves
•  CN IX: The Glossopharyngeal Nerve
– Function: Mixed (sensory and motor)
•  Sensory function: tongue pain
•  Motor function: swallowing
– Origin:
•  Sensory: posterior 1/3 of the tongue
•  Motor: salivary gland
The Cranial Nerves
•  CN IX: The Glossopharyngeal Nerve
(continued)
– Foramen: jugular foramen
– Destination:
•  Sensory: pons
•  Visceral motor: parotid salivary gland
•  Somatic motor: pharyngeal muscles for swallowing
Pons
N VII
N VI
Otic ganglion
NV
N VIII
GLOSSOPHARYNGEAL
NERVE (N IX)
Medulla oblongata
Inferior (petrosal)
ganglion
Superior (jugular)
ganglion
Lingual branch
Pharyngeal branches
Parotid salivary
gland
Carotid sinus
branch
Carotid body
Carotid sinus
Common carotid artery
The Cranial Nerves
•  CN X: The Vagus Nerve
– Function:
•  Sensory: information from organs
•  Motor: sends information to the organs
– Origin:
•  Sensory: from the organs
•  Motor: medulla oblongata
The Cranial Nerves
•  CN X: The Vagus Nerve (continued)
– Foramen: jugular foramen
– Destination:
•  Sensory: autonomic centers of the medulla oblongata
•  Somatic motor: muscles of the palate and pharynx
•  Visceral motor: respiratory, cardiovascular, and
digestive organs
VAGUS
NERVE (N X)
Superior
pharyngeal
branch
Medulla oblongata
Auricular branch
to external ear
Inferior
ganglion of
vagus nerve
Superior
laryngeal nerve
Internal branch
External branch
Cardiac branches
Recurrent
laryngeal nerve
Cardiac plexus
Left lung
Right lung
Liver
Anterior
vagal trunk
Stomach
Pancreas
Spleen
Celiac
plexus
Colon
Small intestine
Hypogastric
plexus
Superior ganglion
of vagus nerve
Pharyngeal branch
Superior laryngeal nerve
The Cranial Nerves
•  CN XI: The Accessory Nerve
– Function:
•  Motor: controls the sternocleidomastoid, trapezius,
palate, pharynx, and larynx muscles
– Origin: spinal cord and medulla oblongata
– Foramen: jugular foramen
– Destination:
•  Internal branch: muscles of the palate, pharynx, and
larynx
•  External branch: sternocleidomastoid and trapezius
muscles
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal,
pharyngeal, and laryngeal
muscles with vagus nerve
Intrinsic muscles
of tongue
Trigeminal nerve (N V)
Medulla oblongata
Cranial root of N XI
Spinal
root of N XI
Styloglossus muscle
External
branch of N XI
Genioglossus muscle
Geniohyoid muscle
Spinal cord
Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Trapezius muscle
Sternocleidomastoid
muscle
Sternohyoid muscle
Sternothyroid muscle
Ansa cervicalis
(cervical plexus)
Omohyoid muscle
The Cranial Nerves
•  CN XII: The Hypoglossal Nerve
– Function:
•  Motor: controls tongue movement
– Origin: medulla oblongata
– Foramen: hypoglossal canal
– Destination: tongue muscles
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal,
pharyngeal, and laryngeal
muscles with vagus nerve
Intrinsic muscles
of tongue
Trigeminal nerve (N V)
Medulla oblongata
Cranial root of N XI
Spinal
root of N XI
Styloglossus muscle
External
branch of N XI
Genioglossus muscle
Geniohyoid muscle
Spinal cord
Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Trapezius muscle
Sternocleidomastoid
muscle
Sternohyoid muscle
Sternothyroid muscle
Ansa cervicalis
(cervical plexus)
Omohyoid muscle
CRANIAL NERVES
Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly!
Some Say Marry Money, But My Brother Says Big Business Makes Money! (sensory/motor/both)
SMB
From
#
Name
To
I
Olfactory
S
olfactory epithelium
cerebrum
II
Optic
S
retina
thalamus
III
Occulomotor
M
eye muscles
midbrain
IV
Trochlear
M
eye muscle SO
midbrain
V
Trigeminal
B
eye + jaw area
pons
VI
Abducens
M
eye muscle LR
pons
VII
Facial
B
motor + sensory of face area
pons
VIII
S
inner ear
pons + medulla oblongata
IX
Vestibulocochlear
(Acoustic)
Glossopharyngeal
B
tongue + pharynx
medulla oblongata
X
Vagus
B
visceral organs
medulla oblongata
XI
Accessory
(Spinal Acc.)
M
pharynx + neck muscles
medulla oblongata + spinal cord
XII
Hypoglossal
M
tongue muscles
medulla oblongata