“I am a brain, Watson. The rest
of me is a mere appendix.”
― Arthur Conan Doyle, The
Adventure of the Mazarin Stone
NEUROANATOMY
The Form of the Brain
Directional terms
superior
lateral
medial
posterior
anterior
inferior
Protecting The Brain
• Skin
• Periosteum = leathery
covering of cranial bones
• Cranium = bone w/fixed
joints
• Meninges
Meninges
• Dura mater = tough fibrous tissue covering the brain.
• Contains blood vessels that nourish the brain.
• Holds in the cerebral-spinal fluid (CSF)
• Arachnoid Space
• Pia mater
Sub- v. Epidural Hematomas
• Epidural = Inflammation between dura and skull
• Subdural = between arachnoid space and dura
Cerebro-Spinal Fluid (CSF)
• CSF = plasma ultrafiltrate that bathes and protects the
CNS.
• Produced by the choroid plexus
(tissue in the lateral ventricles & 4th ventricle)
• Hydrocephalus = Inflammation resulting from
obstruction of the aqueduct connecting the third &
fourth ventricles
Major Regions of the Brain
Cerebrum
Cerebellum
Spinal cord
Cerebral Cortex
• The outer
layer of
grey
matter of
Cerebral Cortex
the cerebrum
• Grey matter
consists of soma (cell bodies)and
unmyelinated axons
• White matter consists of myelinated axons
Soma
Axons
Cerebral Topography
• Gyri – Elevated ridges “winding” around the brain
• Cingulate Gyrus – Just above the corpus callossum
• Sulci – Small grooves dividing the gyri
• Central Sulcus – Divides the Frontal Lobe from the Parietal Lobe
• Fissures – Deep grooves, generally dividing large
regions/lobes of the brain
• Longitudinal Fissure – Divides the two Cerebral Hemispheres
• Transverse Fissure – Separates the Cerebrum from the Cerebellum
• Sylvian/Lateral Fissure – Divides the Temporal Lobe from the Frontal
and Parietal Lobes
Specific Sulci/Fissures:
Central Sulcus
Longitudinal Fissure
Sylvian/Lateral
Fissure
Transverse Fissure
http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
http://www.dalbsoutss.eq.edu.au/Sheepbrains_Me/human_brain.gif
Cerebral Lobes
• Frontal
• Parietal
• Temporal
• Occipital
Frontal Lobe
• The frontal lobe is located
deep to the frontal bone.
• Functions/actions:
• Memory formation
• Emotions
• Decision
Making/Reasoning
• Personality
• Generally, the left side
of the brain controls the
right side of the body
Frontal Lobe –
Cortical Regions
Primary Motor
Cortex/ Precentral
Gyrus
Broca’s Area
Orbitofrontal
Cortex
Olfactory Bulb
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Primary Motor Cortex
• Controls movements of
the body
• Betz cells  alpha motor
neurons (spinal cord) 
muscle fibers
• The motor cortex contains
a rough “map” of the body,
with controls for the toes
(top) to the mouth
(bottom) in overlapping
regions
Motor Homunculus
• Proportional model of organs to density of neural
tissue devoted to said muscle/structure
Broca’s v. Wernicke’s Area
• BROCA =Located on the
right frontal lobe
• Controls facial neurons,
speech, and language
comprehension
• WERNICKE = located
on left temporal lobe
• Controls content of
speech and language
development
Orbitofrontal Cortex
• One of the least explored and understood regions of
the cerebral cortex
• Located just above the orbits (eye sockets), in the
frontal lobe
• Involved in adaptive learning and “personality” of
an individual
Phineas Gage
Olfactory Bulb
• The most rostral (forward) part
of the brain in most vertebrates,
but is on the inferior side of the
brain in humans
• Olfactory receptor neurons in
the nasal cavity receive the
smells, and transmit them to the brain
Parietal Lobe
• Where? The parietal lobe of the brain is located
deep to the parietal bone of the skull
• What Functions?
• Sensory Integration
• Proprioception: awareness of body/body parts
in space and in relation to
each other)
Parietal Lobe – Cortical Regions
Primary
Somatosensory
Cortex/
Postcentral Gyrus
Somatosensory
Association
Cortex
Primary
Gustatory Cortex
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Somatosensory Cortex
• Processing of tactile, temperature, nociceptive
(pain), and proprioceptive (spatial) information
• Neurons are also organized
according to the type of
sensation to which they
respond (i.e. pressure,
temperature, pain)
Somatosensory Homunculus
• This model shows
what a man's body
would look like if
each part grew in
proportion to the
area of the cortex of
the brain concerned
with its sensory
perception
Parietal Lobe – Other Cortical Regions
• Somatosensory Association Cortex
• Assists with integration/interpretation of
sensations relative to body position and
orientation in space (kinesthetic awareness)
and hand-eye coordination
• Primary Gustatory Cortex
• Primary site of interpretation of gustation/taste
Occipital Lobe
• The occipital lobe is located deep to the
occipital bone of the skull
• Functions:
• Processing, integration,
interpretation of vision
and visual stimuli
Occipital Lobe – Cortical Regions
Primary Visual
Cortex
Visual
Association Area
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Occipital Lobe – Cortical Regions
• Primary Visual Cortex
• Primary area of brain responsible for sight.
• Receives information via the optic nerve
• Visual Association Area
• Interprets information acquired through the
primary visual cortex
Temporal Lobe
• The temporal lobes are located on the sides of
the brain, deep to the temporal bones of the skull
• Functions:
• Hearing
• Organization/
comprehension of
language
• Information retrieval
(memory and
memory retrieval)
Primary
Auditory Cortex
Wernike’s Area
Primary Olfactory
Cortex (Deep)
Conducted from Olfactory Bulb
Temporal LobeCortical Regions
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Temporal Lobe – Cortical Regions
• Primary Auditory Cortex
• Responsible for hearing
• Primary Olfactory Cortex
• Interprets the sense of smell once it reaches the
cortex via the olfactory bulbs
• Wernicke’s Area
• Located on the left temporal lobe
• Language comprehension
Cerebellum
• “Little brain”, located inferior
to the cerebrum
• Functions:
• Motor control – doesn’t originate movement (i.e.
primary motor cortex) but contributes to motor
programs
• Attention & language (?)
• Regulating fear and pleasure responses (?)
• Composed of highly regularly arranged Purkinje
cells (large neurons with many dendritic spines)
and Granule cells (small neurons)
Brainstem
• The posterior region of the brain
• Continuous tissue with the spinal column
• All information relayed between the body and
brain must pass through the brainstem
Segments of Brainstem
• The brainstem is composed of three segments:
• Medulla oblongata
• Pons
• Midbrain
Medulla Oblongata
• Lower half of the brainstem
• Contains autonomic centers re:
• Cardiac function
• Respiratory function
• Vomiting
• Vasomotor
Pons
• Relay action potentials from the forebrain to the
cerebellum
• Deals primarily with:
•
•
•
•
Sleep
Respiration
Swallowing
Bladder
control
• Hearing
• Posture
•
•
•
•
•
Equilibrium
Taste
Eye movement
Facial expressions
Facial sensation
Midbrain
• Located superior to the pons
• Associated with:
• Vision
• Hearing
• Motor Control
• Sleep/awake
• Arousal (alertness)
• Temperature regulation
Limbic System
• Associated with higher order behaviors
• Hippocampus: corticosteroid production, spatial
relations; long term memory
• Amygdala: reward, fear, mating, response to stress
• Limbic cortex: judgment, insight, motivation, mood,
• Fornix: relay signals from hippocampus to hypothalamus