Anatomy of the
Brain and Cranial
Nerves
1
The Nervous System can be
divided in:
 Central Nervous System (CNS)
Brain and Spinal Cord
 Peripheral Nervous System (PNS)
Cranial and spinal nerves, ganglia, sensory
receptors
2
Division of the Peripheral Nervous
System
 Sensory or afferent
Somatic
Visceral
 Motor or efferent
Somatic - voluntary
Visceral or Autonomic Nervous System
(ANS) - involuntary
Sympathetic
Parasympathetic
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Major regions and landmarks
 Six regions in the adult brain
Cerebrum
Diencephalon
Mesencephalon
Pons
Cerebellum
Medulla oblongata
 Brain contains extensive areas of neural cortex
Layer of gray matter on the surface of the
cerebellum and cerebrum
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The Cerebrum
5
The cerebral hemispheres
 Surface contains gyri, sulci, fissures
 Fissures
Longitudinal fissure separates two
cerebral hemispheres
Transverse fissure separates
cerebellum from cerebrum
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The Cerebrum
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The cerebral hemispheres
 Sulci
Parieto-occipital sulcus separates parietal
from occipital lobe
Lateral sulcus separates temporal from
parietal lobe
Central sulcus separates frontal and parietal
lobe
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The cerebral hemispheres
 Gyri
Precentral gyrus
Poscentral gyrus
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The cerebral lobes
 Frontal
Precentral gyrus
Primary motor area – conscious
control of voluntary movements.
Premotor cortex – memory bank for
skilled motor activities or of patterned
and repetitious nature.
Broca’s area
Located on the left hemisphere.
Controls speech.
10
The cerebral lobes
Prefrontal cortex – responsible for
personality, cognition, intellect. Lesion cause
mental and personality disorder
 Parietal
Primary Somatosensory Area – touch,
pressure, temperature, vibration, and pain
from body wall
Somatosensory association area – interprets
stimulus sent by the above area. Ex:
recognizes objects by touch.
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The cerebral lobes
 Temporal
Primary Auditory area – temporal lobe.
Primary association auditory area – interprets
the sound heard by above area
Wernicke’s area – only on left hemisphere,
between parietal and temporal lobes. Area
responsible for understanding spoken
language
Olfactory area –uncus. Smell area.
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The cerebral lobes
 Occipital
Primary visual area – perception of light
Visual association area – interprets the
images seen on the area above
 Insula
Gustatory cortex
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Cerebral hemispheres - internal
structures
 Gray matter
Cell bodies of the neurons
Dendrites
Small unmyelinated axons
Neuroglias
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Cerebral hemispheres - internal
structures
 White matter
Tracts
Association – connects 2 areas of the
same hemisphere
Projection – connects upper and lower
brain. Ex: internal capsule
Commissure – connects the 2
hemispheres.
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Tracts
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Sagittal Section
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Cerebral hemispheres - internal
structures
 Corpus callosum
Connects the 2 hemispheres
 Fornix
Connects limbic system areas
 Septum pellucidum
Separates the 2 lateral ventricles
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Cerebral hemispheres - internal
structures
 Basal Nuclei – regulation of voluntary motor
activities. Allows smooth movements.
Caudate Nucleus
Putamen
Globus pallidus
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The Diencephalon
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21
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Diencephalon: external view
 Olfactory tract
 Olfactory bulb
 Optic nerve
 Chiasma optic
 Pituitary gland or hypophysis
 Mammilary bodies – relay for olfaction
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The diencephalon is composed of
 Epithalamus
 Hypothalamus
 Thalamus
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Sagittal Section
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Figure 14.12b
The Epithalamus
 Roof of the third ventricle
 Contains choroid plexus
 Contains pineal gland
Regulates sleep-awake cycle
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The thalamus
 Relay area for impulses
 Two large lobes of gray matter
 Interthalamic adhesion or intermediate mass

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The hypothalamus
 Autonomic center for regulation of body
temperature, water balance, etc
 Secretes hormones
 Mammilary bodies – relay station for olfaction
 Pituitary glands – secretes hormones
 Optic chiasm
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The Brain Stem
Midbrain
Cerebral Aqueduct – connects third and forth
ventricles
Cerebral peduncles – connects pons to
cerebrum
Corpora quadrigemina
Superior colliculi – visual reflex center
Inferior colliculi – auditory reflex center
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The Brain Stem
 Pons
Consists of tracts and nuclei
Connects brain to lower CNS
• Medulla Oblongata
• Tracts
• Decussation of the pyramids
• Autonomic reflex centers – heart rate, blood
pressure, vomiting, swallowing, respiratory
rhythm
• Olives
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PART 2
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Cerebellum
 Two hemispheres connected by the vermis
 Arbor vitae – white matter
 Cortex of gray matter
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The Cerebellum
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The Cerebellum
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The cranial meninges
 Dura mater
 Falx cerebri-formed by dura mater that
dips into the longitudinal fissure and
separates the 2 hemispheres
 Falx cerebelli – separate the two
cerebellar hemispheres
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The cranial meninges – dura
mater
 Superior sagittal Sinus – collects blood from the
brain
 Tentorium cerebelli – separates the cerebrum
from the cerebellum
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The cranial meninges
 Arachnoid
 Subarachnoid space
 Filled with CSF
 Arachnoid villi – projections of the mater
that protrude through the dura
 For the CSF to drain back to the venous
circulation
37
The cranial meninges
 Pia mater
 Highly vascular
 Covers the entire brain
 Meningites
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The Relationship among the
Brain, Cranium, and Meninges
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Ventricles of the brain
Filled with cerebrospinal fluid (CSF)
 Lateral ventricles
Septum pellucidum
Interventricular foramina or foramen of
Monro
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Ventricles of the brain
 Third ventricle
Cerebral aqueduct
 Forth ventricle
3 Apertures
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Ventricles of the Brain
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Cerebrospinal fluid (CSF)
 CSF cushions delicate neural structures
 Supports the brain
 Pathway of CSF
Produced at the Choroid plexus
Travels through the apertures on the 4th
ventricle to the subarachnoid space
Diffuses across the arachnoid villus
(granulation) into the superior sagittal sinus
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The Circulation of CSF
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Cranial Nerves
 12 pairs of cranial nerves
 To help to remember
 “Old Opie Occasionally Tries Trigonometry And
Fells Very Gloomy Vague And Hypoactive”
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The Cranial Nerves
PLAY
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Cranial Nerves
Number
I
II
III
IV
V
Name
Olfactory (sens)
Optic (sens)
Oculomotor
(mot)
Trochlear (mot)
Major Functions
Smell
Vision
Eye movement
Eye movement
Trigeminal (mix) Chewing muscles, head
and face sensation
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Cranial nerves
VI
Abducens (mot)
Eye movement
VII
Facial (mix)
Face expression,
taste
VIII
Vestibulocochlear
(sen)
Vestibular: posture
and balance
Cochlear: hearing
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Cranial Nerves
IX
X
XI
XII
Glossopharingeal Swallowing, taste, general
(mix)
sensation for pharynx
Vagus (mix)
Visceral muscle movement
and taste sensation
Accessory (mot) Swallowing, and head
movement
Hypoglossal
Movement of tongue for
(mot)
speaking, swallowing and
mixing food
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Brain Dissection
Whole Brain
Pia-Arachnoid
Gyrus
Sulcus
Fissure
Transverse
Longitudinal
Cerebrum
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Brain Dissection
Pons
Medulla Oblongata
Cerebellum
Cranial nerves:
I (bulb, tract)
II (nerve, chiasma)
 III
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Brain Dissection
Colliculi
Superior
Inferior
Pineal Gland
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Brain Dissection
Sagittal Cut
Diencephalon
Epithalamus
Thalamus
Hypothalamus
Ventricles
Lateral, third, forth
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Brain Dissection
Septum pellucidum
Corpus callosum
Fornix
Arbor vitae (cerebellum)
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