Download brain anatomy - Sinoe Medical Association

The Brain
Danil Hammoudi.MD
New Terms:
Brain Division
Telencephalon Diencephalon
Telencephalon
–Cerebral
Cortex
–Limbic
system
–Basal
Ganglia
Mesencephalon Metencephalon Myelencephalon
Pons:
Cerebellum:
Medulla
Cell bodies in CNS: nuclei
Cell bodies in PNS: ganglia
Nerves: bundles of axons!
•
Key words that you need to know
•
Cerebrum :
– Cerebral hemispheres
– Longitudinal fissures
– Cerebral cortex
– Sulcus
– Gyri
– all lobes
– Gyruses
– Insula
– Cerebral white matter
– Corpus callosum
– Fornix
– Septum pellucidum
– ventricles
•Cerebellum
•Transverse fissure
•Vermis
•Cerebellar
hemispheres
•Arbor vitae
•Cranial nerves
•Olfactive
•Olfactive bulbs
•Olfactory tracts
•Optic nerves
•Optic chiasma
•Oculomotor nerves
•Trigeminal nerves
•
Diecephalon
– Thalmus
– Hypothalamus
– Intermediate mass
– Mamillary bodies
– Pituitary gland
– Infundibulum
– Choroid plexus
– 3rd ventricle
– Csf
Brain stem
– Midbrain
– Tectum
– Corpora quadregemina
– Superior and inferior
colliculi
– Pons
– Nuclei
– Medulla oblongata
[medulla]
– Cerebral aquaduct
– 4th ventricle
Cerebrum
Cerebrum -The largest division of the brain.
•The cerebrum is divided in to two hemispheres, the right and left
hemispheres each of which is divided into four lobes
•The dividing point is a deep grove called the longitudal cerebral
fissure.
•The different sides of the cerebrum do different things for the
opposite sides of the body.
•The right side of the cerebrum controls things such as imagination
and 3-D forms.
•The other side of the brain, the left side, controls numbering skills,
posture, and reasoning.
Major Structures of the Cortex
•4 Lobes
–Frontal Lobe
–Parietal Lobe
–Occipital Lobe
–Temporal Lobe
•Major Fissures
–Central Sulcus
–Longitudinal Fissure
–Sylvian Fissure
•The lobes are distinguished both structurally and functionally
Cerebral hemisphere (hemispherium cerebrale)
•Is defined as one of the two regions of the brain that are delineated by the body's median
plane.
•The brain can thus be described as being divided into left and right cerebral
hemispheres. Each of these hemispheres has an outer layer of grey matter called the
cerebral cortex that is supported by an inner layer of white matter.
• The hemispheres are linked by the corpus callosum, a very large bundle of nerve fibers,
and also by other smaller commissures, including the anterior commissure, posterior
commissure, and hippocampal commissure.
•These commissures transfer information between the two hemispheres to coordinate
localized functions.
• The architecture, types of cells, types of neurotransmitters and receptor subtypes are all
distributed among the two hemispheres in a markedly asymmetric fashion.
• However, it must be noted that, while some of these hemispheric distribution differences
are consistent across human beings, or even across some species, many observable
distribution differences vary from individual to individual within a given species.
Figure 12.6c: Lobes and fissures of the cerebral hemispheres, p. 435.
Anterior
Longitudinal
fissure
Frontal lobe
Cerebral veins
and arteries
covered by
arachnoid
Parietal lobe
Right
Cerebral
hemisphere
Occipital
lobe
Left cerebral
hemisphere
Posterior
(c)
Cerebral Features:
• Gyri – Elevated ridges “winding” around the brain.
• 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
Gyri (ridge,
circumvoluti
on)
Sulci
(groove)
Fissure
(deep groove)
http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif
The medial longitudinal fissure (or longitudinal cerebral fissure, or longitudinal
fissure, or interhemispheric fissure) is the deep groove which separates the two
hemispheres of the vertebrate brain.
The falx cerebri, a dural brain covering, lies within the medial longitudinal fissure.
1. right cerebral
cortex
2. longitudinal
fissure
3. cerebellum
4. frontal lobe
5. central sulcus
6. parietal lobe
1.
2.
3.
4.
5.
falx cerebri
location of inferior sagittal sinus
location of superior sagittal sinus
location of straight sinus
tentorium cerebelli
Figure 12.25: Partitioning folds of dura mater in the cranial cavity, p. 465.
Falx cerebri
Superior
sagittal sinus
Straight
sinus
Tentorium
cerebelli
Crista galli of the
ethmoid bone
Cavernous
sinus
Internal carotid
artery
Falx cerebelli
Falx cerebri
Sulcus
•a sulcus is a depression or fissure in the surface of the brain.
• It surrounds the gyri, creating the characteristic appearance of the brain in humans
and other large mammals.
•Large furrows (sulci) that divide the brain into lobes are often called fissures.
•The large furrow that divide the two hemispheres - the interhemispheric fissure - is
very rarely called a "sulcus".
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
Central sulcus= between frontal and parietal lobes.
Frontal lobe:
precentral gyrus: motor neurons.
Parietal lobe:
Poscentral gyrus: somatesthetic sensation (cutaneous touch, pain,
heat, muscles and joints).
MAP of motor and of sensory control (homunculus)
The Four
Ventricles
Lateral Ventricles:
largest
Third Ventricle:
“wall” divides brain
into symmetrical
halves
Cerebral aqueduct:
long tube that
connects 3rd to 4th
ventricle
Fourth Ventricle
Figure 12.5: Ventricles of the brain, p. 434.
Lateral
ventricle
Lateral
ventricle
Third
ventricle
Anterior
horn
Septum
pellucidum
Third
ventricle
Posterior
horn
Cerebral
aqueduct
Interventricular
foramen
Inferior
horn
Cerebral
aqueduct
Fourth
ventricle
Fourth
ventricle
Median
aperture
Lateral
aperture
Central
canal
Central
canal
(a) Anterior view
(b) Left lateral view
The Four
Ventricles
• Protects Brain
From Trauma
• Provides
Pathway for
Circulation of
CSF
•
Continuous w/each
other + central
canal of spinal cord
Coronal Section Level of the
LGB's
Figure 12.11a: Basal nuclei, p. 444.
Fibers of
corona radiata
Corpus
striatum
Caudate
nucleus
Thalamus
Lentiform
nucleus
Tail of caudate
nucleus
Internal capsule
(projection fibers
run deep to
lentiform nucleus)
(a)
Lobes and fissures of the cerebral hemispheres,
Anterior
Longitudinal
fissure
Frontal lobe
Cerebral veins
and arteries
covered by
arachnoid
Parietal lobe
Left cerebral
hemisphere
Right
cerebral
hemisphere
Posterior
(c)
Occipital
lobe
Left cerebral
hemisphere
Brain stem
(d)
Transverse cerebral
fissure
Cerebellum
LOBES
Cortical Function
•Frontal Lobe
–Higher thought processing; decision making;
abstract thinking
–Primary “precentral” motor area
•Parietal Lobe
–Primary “postcentral” somatosensory area:
sensation of muscles, organs, and skin
•Occipital Lobe
–Visual processing
•Temporal Lobe
–Auditory & equilibrium processing
–Left temporal lobe involved in speech and
comprehension of language
Frontal
Lobe
The
Cerebral
Cortex
Primary
Parietal
Motor Primary
Lobe
Area Sensory
Area
Premotor
leg
Area
trunk
Sensory
arm
Association
Higher
Area
Intellectual
hand
Functions
Visual
face
Association
tongue
Area
Speech
Primary
Language
Motor
Visual
Comprehension
Area
Primary & Formation
Area
Auditory
Area
Memory
Temporal
Lobe
Occipital
Lobe
Lobes of the Brain (4)
•
•
•
•
Frontal
Parietal
Occipital
Temporal
http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
* Note: Occasionally, the Insula is considered the fifth lobe. It is located
deep to the Temporal Lobe.
Figure 12.8a: Functional and structural areas of the cerebral cortex, p. 437.
Central sulcus
Primary
somatosensory
cortex
Somatosensory
association area
Primary motor area
3 1
Premotor cortex
4
6
Frontal
eye field
5
Gustatory cortex
(in insula)
45
43
44
41 42
Broca's area
(outlined by dashes)
Prefrontal cortex
(a)
Taste
Wernicke's area
(outlined by dashes)
Executive area for
task management
Solving complex,
multitask problems
Somatic
sensation
7
8
Working memory
for spatial tasks
Working memory for
object-recall tasks
2
11
47
22
22
19 18
17
Primary
visual
cortex
Visual
association
area
Auditory
association
area
Primary
auditory
cortex
Vision
Hearing
Figure 12.6a-b: Lobes and fissures of the cerebral hemispheres, p. 435.
Central sulcus
Precentral gyrus
Postcentral gyrus
Parietal lobe
Frontal lobe
Parieto-occipital sulcus
(on medial surface
of hemisphere)
Lateral sulcus
Frontal lobe Central sulcus
Occipital lobe
Temporal lobe
Transverse
cerebral fissure
Cerebellum
Pons
Medulla oblongata
(a)
Spinal cord
Gyri of insula
Gyrus
Cortex
(gray matter)
Sulcus
White matter
Fissure
(a deep sulcus)
Temporal lobe
(pulled down)
(b)
Lobes and fissures of the cerebral hemispheres, p. 435.
Central sulcus
Precentral gyrus
Postcentral gyrus
Parietal lobe
Frontal lobe
Parieto-occipital sulcus
(on medial surface
of hemisphere)
Lateral sulcus
Occipital lobe
Temporal lobe
Transverse
cerebral fissure
Cerebellum
Pons
Medulla oblongata
(a)
Spinal cord
Gyrus
Cortex
(gray matter)
Sulcus
White matter
Fissure
(a deep sulcus)
Figure 12.8b: Functional and structural areas of the cerebral cortex, p. 437.
Premotor
cortex
Corpus
callosum
Cingulate
gyrus
Primary
motor area
4
6
Central sulcus
Primary somatosensory
cortex
8
6
Frontal eye field
4
8
1-3
5
Parietal lobe
Prefrontal
cortex
Somatosensory
association area
7
19
Parieto-occipital
sulcus
Occipital
lobe
Processes emotions
related to personal
and social interactions
18
18
17
34
Orbitofrontal
cortex
28
Olfactory bulb
Olfactory tract
(b)
Fornix
Temporal lobe
Uncus
Primary olfactory
cortex
Calcarine
sulcus
Visual
association
area
Primary
visual cortex
Parahippocampal
gyrus
Lobes of the Brain - Frontal
• The Frontal Lobe of the brain is located deep to the
Frontal Bone of the skull.
• It plays an integral role in the following functions/actions:
- Memory Formation
- Emotions
- Decision Making/Reasoning
- Personality
(Investigation:
Investigation Phineas
(PhineasGage)
Gage)
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Frontal Lobe - Cortical Regions
• Primary Motor Cortex (Precentral Gyrus) – Cortical site
involved with controlling movements of the body.
• Broca’s Area – Controls facial neurons, speech, and language
comprehension. Located on Left Frontal Lobe.
– Broca’s Aphasia – Results in the ability to comprehend speech, but
the decreased motor ability (or inability) to speak and form words.
• Orbitofrontal Cortex – Site of Frontal Lobotomies
* Desired Effects:
- Diminished Rage
- Decreased Aggression
- Poor Emotional
Responses
* Possible Side Effects:
- Epilepsy
- Poor Emotional Responses
- Perseveration (Uncontrolled,
repetitive actions, gestures, or words)
• Olfactory Bulb - Cranial Nerve I, Responsible for sensation of Smell
Investigation (Phineas Gage)
Primary Motor
Cortex/ Precentral
Gyrus
Broca’s Area
Orbitofrontal
Cortex
Olfactory Bulb
Regions
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Parietal Lobe - Cortical Regions
• Primary Somatosensory Cortex (Postcentral
Gyrus) – Site involved with processing of tactile
and proprioceptive information.
• Somatosensory Association Cortex - Assists
with the integration and interpretation of sensations
relative to body position and orientation in space.
May assist with visuo-motor coordination.
• Primary Gustatory Cortex – Primary site
involved with the interpretation of the sensation of
Taste.
Lobes of the Brain - Parietal Lobe
• The Parietal Lobe of the brain is located deep to the
Parietal Bone of the skull.
• It plays a major role in the following functions/actions:
- Senses and integrates sensation(s)
- Spatial awareness and
perception
(Proprioception - Awareness of
body/ body parts in space and
in relation to each other)
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
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
Regions
Lobes of the Brain – Occipital Lobe
• The Occipital Lobe of the
Brain is located deep to the
Occipital Bone of the Skull.
• Its primary function is the
processing, integration,
interpretation, etc. of VISION and
visual stimuli.
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Occipital Lobe – Cortical Regions
• Primary Visual Cortex – This is the primary
area of the brain responsible for sight recognition of size, color, light, motion,
dimensions, etc.
• Visual Association Area – Interprets
information acquired through the primary visual
cortex.
Primary Visual
Cortex
Visual
Association Area
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Regions
Lobes of the Brain – Temporal Lobe
• The Temporal Lobes are located on the sides of the
brain, deep to the Temporal Bones of the skull.
• They
play an integral role
in the following functions:
- Hearing
- Organization/Comprehension
of language
- Information Retrieval
(Memory and Memory Formation)
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. (Not visible on the superficial cortex)
• Wernicke’s Area – Language comprehension.
Located on the Left Temporal Lobe.
- Wernicke’s Aphasia – Language comprehension
is inhibited. Words and sentences are not clearly
understood, and sentence formation may be inhibited or
non-sensical.
Primary
Auditory Cortex
Wernike’s Area
Primary Olfactory
Cortex (Deep)
Conducted from Olfactory Bulb
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Regions
• Arcuate Fasciculus - A white matter tract that connects Broca’s Area and
Wernicke’s Area through the Temporal, Parietal and Frontal Lobes. Allows
for coordinated, comprehensible speech. Damage may result in:
- Conduction Aphasia - Where auditory comprehension and speech
articulation are preserved, but people find it difficult to repeat heard
speech.
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Click the Region to see its Name
Korbinian Broadmann - Learn about the man who divided the Cerebral Cortex into 52 distinct regions:
http://en.wikipedia.org/wiki/Korbinian_Brodmann
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Insular cortex
lies deep to the brain's
lateral surface, within the
lateral sulcus which
separates the temporal
lobe and inferior parietal
cortex.
These overlying cortical
areas are known as
opercula (meaning "lids"),
and parts of the frontal,
temporal and parietal
lobes form opercula over
the insula. The latin name
for the insular cortex is
lobus insularis.
insular cortex is also
known by the name
Island of Reil,
1.Gyri breves insula
2.Gyri longi insula
3.Limen insula
4.Sulcus centralis
insula
5.Sulcus circularis
insula
Insula:
Implicated in memory encoding.
Integration of sensory information with
visceral responses.
Coordinated cardiovascular response to
stress.
The insular cortex is a complex structure which contains areas that subserve
visceral sensory, motor, vestibular, and somatosensory functions. The role of the
insular cortex in auditory processing was poorly understood until recently. However,
recent case studies indicate that bilateral damage to the insulae may result in total
auditory agnosia. Functional imaging studies demonstrate that the insulae
participate in several key auditory processes, such as allocating auditory attention
and tuning in to novel auditory stimuli, temporal processing, phonological
processing and visual-auditory integration. These studies do not clarify the issue of
further specialisation within the insular cortex, e.g. whether the posterior insulae are
primarily sensory areas, while the anterior insulae serve mainly as
integration/association auditory areas, two hypotheses that would be compatible
with the cytoarchitectonic structure and connectivity of the insulae.
The insula (Island of Reil) and its role in auditory processing. Literature review.
•Bamiou DE,
•Musiek FE,
•Luxon LM.
Neuro-Otology Department, National Hospital for Neurology and Neurosurgery, Queen Square,
London WC1N 3BG, UK. [email protected]
Figure 12.14: Ventral aspect of the human brain, showing the three regions of the brain stem, p. 447.
Frontal lobe
Olfactory bulb
(synapse point
of cranial nerve I)
Optic chiasma
Optic nerve (II)
Optic tract
Mammillary body
Pons
Temporal lobe
Medulla
Cerebellum
Spinal cord
Midbrain
Figure 12.9: Motor and sensory areas of the cerebral cortex, p. 438.
Toes
Face
Genitals
se
o
N
ce
a
F
s
Lip
th
Teems
Gu
Jaw
e
Tongu
Lips
Jaw
Tongue
Swallowing
Arm
Ey
e
Ne
c
Br k
ow
Eye
Elb
ow
Fo
rea
rm
Ha
nd
Fi
ng
er
Th
um s
b
Th
um
b
Head
Neck
Trunk
Hip
Sensory
Leg
Knee
Hip
Trunk
Arm
w
Elbo
ist
Wr
nd
Ha
s
er
ng
Fi
er
Should
Motor
Motor cortex
(precentral gyrus)
Pharynx
Intraabdominal
Figure 12.10a-b: Types of fiber tracts in white matter, p. 442.
Association
fibers
Projection
fibers
Thalamus
and internal
capsule
(a)
Corpus
callosum
(commissural
fibers)
Projection
(internal capsule)
fibers
(b)
DIENCEPHALON
Figure 12.12: Midsagittal section of the brain illustrating the diencephalon and brain stem, p. 445.
Parietal lobe of
cerebral hemisphere
Corpus callosum
Fornix
Choroid plexus
Occipital lobe of
cerebral hemisphere
Thalamus
(encloses third ventricle)
Posterior commissure
Pineal body/gland
(part of epithalamus)
Corpora
quadrigemina
Midbrain
Cerebral
aqueduct
Septum pellucidum
Interthalamic
adhesion
(intermediate
mass of thalamus)
Frontal lobe
of cerebral
hemisphere
Interventricular
foramen
Anterior
commissure
Hypothalamus
Optic chiasma
Pituitary gland
Temporal lobe of
cerebral hemisphere
Arbor vitae
Fourth ventricle
Mammillary body
Pons
Medulla oblongata
Spinal cord
Choroid plexus
Cerebellum
DIENCEPHALON
2 Major Structures
- Thalamus
- Hypothalamus
Thalamus
Selected structures of the diencephalon, p. 445.
- Two lobes that relay sensory projection fiber info
to the cerebral cortex
Hypothalamus
- Lies at the base of the brain
- Controls and regulates the
endocrine system (hormones),
autonomic system, species survival
(the four Fs) and sleeping.
- Contains many nuclei and fiber
tracts
Dorsal nuclei
Paraventricular
nucleus
Medial Lateral Lateral
dorsal posterior
Pulvinar
Anterior
nuclear
group
Reticular
nucleus
Ventral
Ventral Ventral posterior
anterior lateral lateral
Ventral nuclei
(a)
Medial
geniculate
body
Lateral
geniculate
body
Anterior
commissure
Preoptic
nucleus
Anterior
hypothalamic
nucleus
Supraoptic
nucleus
Suprachiasmatic
nucleus
Optic
chiasma
Infundibulum
(stalk of the
pituitary gland)
(b)
Fornix
Dorsomedial
nucleus
Posterior
hypothalamic
nucleus
Lateral
hypothalamic
area
Ventromedial
nucleus
Arcuate
nucleus
Pituitary
gland
Mammillary
body
Thalamus
• All sensory modalities relay through the thalamus
Thalamus – “gateway” to the
cerbral
cortex
Afferent impulses
from all senses
converge and
synapse in the thalamus
Impulses of similar function are sorted out, “edited”,
and relayed as a group to the appropriate area of the
sensory cortex or association areas
All inputs ascending to the cerebral cortex pass
through the thalamus
Plays a key role in mediating sensation, motor
activities, cortical arousal, learning, and memory
Hypothalamus
Below the thalamus, it caps the brainstem and
forms the inferolateral walls of the third ventricle
Mammillary bodies - small, paired nuclei bulging
anteriorly from the hypothalamus - relay stations
for olfactory pathways
Infundibulum – stalk of the hypothalamus
connecting to the pituitary gland
Main visceral control center of the body,
important to overall body homeostasis
Hypothalamus
• A group of nuclei
critical for
regulating
homeostasis, the
four Fs, and
hormones
Hypothalamic Nuclei
Hypothalamic Function
Regulates ANS by controlling activity of centers in brains stem and spinal cord
Regulates blood pressure, rate and force of heartbeat, digestive tract motility,
respiratory rate and depth, pupil size, and many other visceral activities
Center for emotional response - involved in perception of pleasure, fear, rage
Regulates body temperature – the body’s “thermostat”
Regulates food intake - feelings of hunger and satiety
Regulates sleep-wake cycle
Endocrine Functions of the Hypothalamus
Releasing hormones control the secretion of hormones by the anterior pituitary
Stimulates ADH release from the posterior pituitary
Anti-diuretic hormone- causes kidneys to retain water
Figure 12.10c: Types of fiber tracts in white matter, p. 442.
Superior
Corpus callosum
(commissural
fibers)
Corona
radiata
Longitudinal
fissure
Gray matter
White matter
Lateral
ventricle
Caudate
Basal nuclei
(ganglia)
Putamen
Fornix
Globus pallidus
Third
ventricle
Internal
capsule
Projection
fibers
Decussation
of pyramids
(c)
Thalamus
Pons
Medulla
oblongata
Figure 12.11b: Basal nuclei, p. 444.
Anterior
Cerebral cortex
Cerebral white matter
Corpus callosum
Anterior horn
of lateral ventricle
Caudate nucleus
Third ventricle
Putamen
Lentiform
Globus pallidus nucleus
Thalamus
Inferior horn
of lateral ventricle
(b)
Posterior
Figure 12.15a: Relationship of the brain stem and the diencephalon, p. 448.
Optic nerve
Optic chiasma
Floor of
hypothalamus
Mammillary
body
Trochlear
nerve (IV)
Thalamus
Optic tract
Infundibulum
(pituitary removed)
Oculomotor nerve (III)
Crus cerebri of
cerebral peduncles
(midbrain)
Pons
Trigeminal nerve (V)
Middle
cerebellar
peduncle
Abducens nerve (VI)
Hypoglossal
nerve (XII)
Pyramid
Decussation of
pyramids
Spinal
cord
(a) Ventral view
Facial nerve (VII)
Vestibulocochlear
nerve (VIII)
Glossopharyngeal
nerve (IX)
Vagus nerve (X)
Accessory
nerve (XI)
Ventral root
of first cervical
nerve
Figure 12.15b: Relationship of the brain stem and the diencephalon, p. 448.
Thalamus
Optic tract
Crus cerebri of
cerebral peduncles
(midbrain)
Superior colliculus
Infundibulum
Pituitary gland
Trigeminal nerve (V)
Inferior colliculus
Trochlear nerve (IV)
Superior cerebellar
peduncle
Facial nerve (VII)
Vestibulocochlear
nerve (VIII)
Glossopharyngeal
nerve (IX)
Pons
Abducens
nerve (VI)
Middle cerebellar
peduncle
Inferior cerebellar
peduncle
Vagus nerve (X)
Olive
Fasciculus gracilis
Hypoglossal
nerve (XII)
Fasciculus cuneatus
Accessory
nerve (XI)
(b) Left lateral view
Figure 12.15c: Relationship of the brain stem and the diencephalon, p. 449.
Third ventricle
Thalamus
Pineal gland
Lateral geniculate
nucleus
Medial geniculate
nucleus
Superior
colliculus
Inferior
colliculus
Corpora
quadrigemina
of tectum
Midbrain
Trochlear (IV) nerve
Superior cerebellar peduncle
Middle cerebellar peduncle
Anterior wall of
fourth ventricle
Pons
Inferior cerebellar peduncle
Facial (VII) nerve
Vestibulocochlear (VIII) nerve
Medulla
Choroid plexus
(fourth venticle)
Glossopharyngeal (IX) nerve
Posterior median sulcus
Vagus (X) nerve
Fasciculus cuneatus
Accessory (XI) nerve
Fasciculus gracilis
Posterior (dorsal) root
of first cervical nerve
(c) Dorsal view
CRANIAL NERVES:
COMPOSITION
Some are motor nerves
III, IV, VI, XI, XII
Some are sensory nerves
I, II, VIII
Others are mixed nerves
V, VII, IX, X
Some contain autonomic
(preganglionic
parasympathetic) fibers
originating in the brain stem
III, VII, IX, X
Figure 12.16a: Important brain stem nuclei, p. 450.
Dorsal
Cerebral
aqueduct
Superior colliculus
Periaqueductal gray
matter
Reticular
formation
Oculomotor nucleus
Medial lemniscus
Red
nucleus
Substantia
nigra
Corticospinal
fibers
Ventral
(a) Midbrain
Cerebral
peduncle
Figure 12.16b: Important brain stem nuclei, p. 450.
Superior cerebellar
peduncle
Fourth
ventricle
Reticular
formation
Trigeminal
main sensory
nucleus
Trigeminal
motor
nucleus
Middle
cerebellar
peduncle
Pontine
nuclei
Trigeminal nerve
Medial lemniscus
(b) Pons
Fibers of
pyramidal
tract
Pons:
Connects other parts.
several nuclei associated with cranial nerves
respiratory centers.
Cerebellum:
“little brain”
Receives input from proprioceptors (joints,
muscles, tendons).
Refinement/coordination of movement.
CEREBELLUM
Figure 12.17: Cerebellum, p. 452.
Anterior
lobe
Primary
fissure
Posterior
lobe
Horizontal
fissure
Vermis
(b)
(a)
White matter
of cerebellum
Vermis
Brain stem
(midbrain)
Cerebellar
cortex
Deep cerebellar
nuclei
(c)
Caudal
(inferior)
Vermis
(cut)
Purkinje Granule cells Site of basket cells
cells
and stellate cells in
in granular
(d)
outer cortex
layer
(molecular layer)
LIMBIC SYSTEM
Figure 12.18: The limbic system, p. 455.
Cingulate
gyrus
Septum
pellucidum
Anterior
pellucidum
Septal nuclei
Hypothalamus
Olfactory bulb
Mammillary body
Hippocampus
Corpus
callosum
Fornix
Anterior
thalamic nuclei
(flanking
3rd ventricle)
Amygdala
Parahippocampal
gyrus
Dentate gyrus
(deep to the
parahippocampal
gyrus)
Figure 12.19: The reticular formation, p. 455.
Radiations
to cerebral
cortex
Visual
impulses
Reticular formation
Ascending general
sensory tracts
(touch, pain, temperature)
Auditory
impulses
Descending
motor projections
to spinal cord
Figure 12.22: Memory processing, p. 461.
Outside stimuli
General and special sensory receptors
Afferent inputs
Temporary storage
(buffer) in cerebral cortex
Automatic
memory
Data permanently lost
Data selected
for transfer
Short-term
memory
Forget
Forget
Data transfer
influenced by:
Retrieval
Excitement
Rehearsal
Association of
old and new data
Long-term
memory
Data unretrievable
Figure 12.23: Proposed memory circuits, p. 462.
Thalamus
Basal
forebrain
Prefrontal
cortex
Premotor
cortex
Touch
Smell
Hearing
Taste
Vision
Basal
nuclei
Hippocampus
Medial temporal lobe
(hippocampus, etc.)
ACh
Substantia
nigra
Sensory and
motor inputs
Sensory
input
Thalamus
Prefrontal
cortex
Association
cortex
Premotor
cortex
Thalamus
Basal
nuclei
Association
cortex
Dopamine
ACh
Basal
forebrain
(a)
Thalamus
Substantia
nigra
(b)
Figure 12.24a: Meninges, p. 464.
Skin of scalp
Periosteum
Bone of skull
Periosteal
Meningeal
Superior
sagittal sinus
Subdural
space
Subarachnoid
space
(a)
Dura
mater
Arachnoid mater
Pia mater
Arachnoid villus
Blood
vessel
Falx cerebri
(in longitudinal
fissure only)
Figure 12.24b: Meninges, p. 464.
Skull
Scalp
Superior
sagittal sinus
Occipital lobe
Tentorium
cerebelli
Cerebellum
Arachnoid mater
over medulla
oblongata
(b)
Dura mater
Tranverse
sinus
Temporal
bone
Figure 12.26: Formation, location, and circulation of CSF, p. 466.
Superior
sagittal sinus
Superior
cerebral vein
Choroid plexus
Cerebrum covered
with pia mater
Septum
pellucidum
Corpus
callosum
Interventricular
foramen
Third ventricle
Pituitary gland
Cerebral aqueduct
Lateral aperture
Fourth ventricle
Median aperture
Arachnoid
villus
Subarachnoid space
Arachnoid mater
Meningeal dura mater
Periosteal dura mater
Great cerebral vein
Tentorium cerebelli
Straight sinus
Confluence of sinuses
Cerebellum
Choroid plexus
Cerebral vessels
that supply
choroid plexus
Central canal
of spinal cord
Spinal dura mater
Inferior end of
spinal cord
Ependymal
cells
Filum terminale
(inferior end
of pia mater)
Capillary
Connective
tissue of
pia mater
Section
of choroid
plexus
Cavity of Filtrate containing glucose,
Wastes and
ventricle oxygen, vitamins, and
unnecessary
solutes absorbed
ions (Na+, Cl–, Mg2+, etc.)
Figure 12.26: Formation, location, and circulation of CSF, p. 466.
Superior
sagittal sinus
Superior
cerebral vein
Choroid plexus
Cerebrum covered
with pia mater
Septum
pellucidum
Arachnoid
villus
Subarachnoid space
Arachnoid mater
Meningeal dura mater
Periosteal dura mater
Great cerebral vein
Corpus
callosum
Interventricular
foramen
Tentorium cerebelli
Straight sinus
Confluence of sinuses
Third ventricle
Pituitary gland
Cerebral aqueduct
Lateral aperture
Fourth ventricle
Median aperture
Cerebellum
Choroid plexus
Cerebral vessels
that supply
choroid plexus
Central canal
of spinal cord
Spinal dura mater
Inferior end of
spinal cord
Filum terminale
(inferior end
of pia mater)
(b)
choroid plexus
•It produces the cerebrospinal fluid (CSF) which is found within the ventricles of the brain and in
the subarachnoid space around the brain and spinal cord.
•It is comprised of a rich capillary bed, pia mater, and choroid epithelial cells.
•It is located in certain parts of the ventricular system of the brain.
Figure 12.29a: Gross structure of the spinal cord, posterior view, p. 471.
Cervical
enlargement
Dura and
arachnoid
mater
Lumbar
enlargement
Conus
medullaris
Cauda
equina
Filum
terminale
(a)
Cervical
spinal
nerves
Thoracic
spinal
nerves
Lumbar
spinal nerves
Sacral
spinal
nerves
Figure 12.29b: Gross structure of the spinal cord, posterior view, p. 471.
Dura mater
Terminus of
medulla
oblongata
of brain
Sectioned
pedicles of
cervical
vertebrae
Spinal roots
Posterior
median sulcus
of spinal cord
(b)
Figure 12.29c: Gross structure of the spinal cord, posterior view, p. 471.
Spinal cord
Vertebral
arch
Denticulate
ligament
Denticulate
ligament
Posterior
median
sulcus
Arachnoid
mater
Dorsal root
Dura mater
(c)
Figure 12.29d: Gross structure of the spinal cord, posterior view, p. 471.
Spinal cord
Cauda
equina
First lumbar
vertebral arch
(cut across)
Spinous
process of
second lumbar
vertebra
(d)
Conus
medullaris
Filum
terminale
Figure 12.30: Diagrammatic view of a lumbar tap, p. 472.
T12
L5
Ligamentum
flavum
Lumbar
puncture
needle
L44
Vertebral
disc
Dura mater
and arachnoid
Cauda
equina in
subarachnoid
space
Supraspinous
ligament
Filum
terminale
L5
S1
Figure 12.31a: Anatomy of the spinal cord, p. 473.
Epidural space
(contains fat)
Subdural space
Subarachnoid
space
Pia mater
Arachnoid
Dura mater
Spinal meninges
Bone of
vertebra
Dorsal root
ganglion
Body
of vertebra
(a)
Figure 12.31b: Anatomy of the spinal cord, p. 473.
Posterior funiculus
White
Anterior funiculus
columns Lateral funiculus
Posterior median sulcus
Gray commissure
Dorsal (posterior) horn
Gray
Ventral (anterior) horn
matter
Lateral horn
Dorsal root
ganglion
Spinal nerve
Dorsal root
Ventral root
Central canal
Anterior median
fissure
Pia mater
Arachnoid
Spinal mater
(b)
Figure 12.32: Organization of the gray matter of the spinal cord, p. 474.
Dorsal root
(sensory)
Dorsal horn (interneurons)
Dorsal root
ganglion
SS
VS
Somatic sensory neuron
VM
Visceral sensory
neuron
SM
Visceral motor
neuron
Somatic motor neuron
Spinal nerve
Ventral root (motor)
Ventral horn
(motor neurons)
Figure 12.33: Major ascending (sensory) and descending (motor) tracts of the spinal cord, cross-sectional view, p. 475.
Anterior white
commissure
Ascending tracts
Dorsal Fasciculus gracilis
white
column Fasciculus cuneatus
Posterior
spinocerebellar tract
Descending tracts
Lateral
reticulospinal tract
Lateral
corticospinal
tract
Anterior
spinocerebellar
tract
Rubrospinal tract
Lateral
spinothalamic
tract
Anterior
spinothalamic
tract
Medial
reticulospinal tract
Anterior
corticospinal tract
Vestibulospinal tract
Tectospinal tract
Key:
Descending tracts
Ascending tracts
Figure 12.34: Pathways of selected ascending spinal cord tracts, p. 476.
Somatosensory
cortex
Axons of thirdorder neurons
Thalamus
Cerebrum
Midbrain
Cerebellum
Pons
Posterior
spinocerebellar
tract (axons of
second-order
neurons)
Medial lemniscal tract
(axons of second-order neurons)
Nucleus gracilis
Nucleus cuneatus
Medulla oblongata
Fasciculus cuneatus
(axon of first-order sensory neuron)
Pain receptors
Joint stretch
receptor
(proprioceptor)
Axon of
first-order
neuron
Muscle
spindle
(proprioceptor)
(a) Spinocerebellar
pathway
Lateral
spinothalamic
tract (axons of
second-order
neurons)
Cervical spinal cord
Fasciculus gracilis
(axon of first-order sensory neuron)
Lumbar spinal cord
Touch
receptor
Medial lemniscal
pathway
Axons of firstorder neurons
Temperature
receptors
Spinothalamic pathway
(b)
Figure 12.35: Pathways of selected descending spinal cord tracts, p. 480.
Upper motor
neurons
Primary motor
area of
cerebral cortex
Internal capsule
Cerebrum
Red nucleus
Midbrain
Cerebral
peduncle
Cerebellum
Pons
Rubrospinal tract
Pyramids
Decussation
of pyramid
Lateral
corticospinal
tract
Medulla oblongata
Anterior
corticospinal
tract
Cervical spinal cord
Skeletal
muscle
Lumbar spinal cord
Lower motor neurons
(a) Pyramidal (lateral and anterior
corticospinal) tracts
(b) Rubrospinal tract
(an extrapyramidal tract)