Transcript Chapter 15-Brain and Cranial Nervesx

Chapter 15
Brain and Cranial Nerves
Anterior Central sulcus Posterior
Fig. 15.1a (left)
Parietal lobe
Frontal lobe
Gyrus
Sulcus
Parieto-occipital
Cerebrum
sulcus
Lateral sulcus
Occipital lobe
Temporal lobe
Brainstem
Pons
Cerebellum
Medulla
oblongata
Spinal cord
(a) Left lateral view
Cerebral hemispheres
Fig. 15.1b
Anterior
Frontal
lobe
Cerebrum
Temporal
lobe
Occipital
lobe
Posterior
Eye
Olfactory bulb
Optic nerve
Olfactory tracts
Optic chiasm
Pituitary gland
Optic tract
Mammillary bodies
Midbrain
Pons
Brainstem
Medulla
oblongata
Cranial nerves
Cerebellum
Anterior
Fig. 15.1c
Frontal lobe
Central sulcus
Parietal lobe
Corpus callosum
Diencephalon
Posterior
Parieto-occipital sulcus
Occipital lobe
Interthalamic
adhesion
Thalamus
Hypothalamus
Pineal gland
Tectal plate
Pituitary gland
Temporal lobe
Midbrain
Brainstem
Pons
Medulla oblongata
Spinal cord
Cerebral aqueduct
Fourth ventricle
Cerebellum
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Fig. 15.2 (left)
Rhombencephalon
Prosencephalon
Mesencephalon
Mesencephalon
Prosencephalon
Rhombencephalon
Spinal cord
Spinal cord
(a) 4 weeks
Myelencephalon
Telencephalon
Optic vesicle
Diencephalon
Metencephalon
Mesencephalon
Optic vesicle
Diencephalon
Mesencephalon
Telencephalon
Metencephalon
Spinal cord
Myelencephalon
Spinal cord
(b) 5 weeks
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Fig. 15.2 (right)
Central sulcus
Cerebrum
Outline of diencephalon
Cerebrum
Outline of diencephalon
Midbrain
Cerebellum
Lateral sulcus
Midbrain
Cerebellum
Pons
Medulla oblongata
Pons
Medulla oblongata
Spinal cord
Spinal cord
(c) 13 weeks
(d) 26 weeks
Cerebrum
Midbrain
Pons
Medulla
oblongata
Thalamus
Pituitary gland
Cerebellum
Spinal cord
(e) Birth
Brainstem
Fig. 15.3
(a)
Gray matter
White matter
Cortex
Inner white matter
Corpus callosum
Internal capsule
Cerebral
nuclei
Lateral ventricle
(a) Coronal section of cerebrum
Cortex (gray matter)
(a)
Inner gray matter
Cerebrum
Cerebellum
Cerebellum
Medulla
oblongata
Fig. 15.3
(b)
(c)
Fourth ventricle
Inner gray matter
Brainstem
Gray matter
Outer white matter
(b) Cerebellum and brainstem
Fig. 15.3
Fourth ventricle
Inner gray
matter
Cerebrum
Cerebellum
Medulla
oblongata
(b)
(c)
Outer white
matter
Fig. 15.3
(d) Spinal cord
Cerebrum
(b)
(c)
Cerebellum
Medulla
oblongata
Central canal
Outer white matter
Inner gray
matter
Spinal cord
(d)
Fig. 15.4
Cranial meninges
Skin of scalp
Periosteum
Bone of skull
Arachnoid
granulation
Periosteal layer
Dura mater
Meningeal layer
Subdural space (potential space)
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Pia mater
Dural venous
sinus (superior
sagittal sinus)
Cerebral cortex
• Connective tissue layers that
separate soft brain tissue from
bones of cranium
• protects blood vessels that supply brain
• contain and circulate cerebrospinal fluid
White matter
Falx cerebri
Fig. 15.4
Cranial meninges
• Dura mater
dura = tough
• dense, irregular connective
tissue
• meningeal layer deep to
periosteal layer (layers
usually fused together)
• where not fused, dural
venous sinuses form; large
veins that drain blood from
brain
Skin of scalp
Periosteum
Bone of skull
Periosteal layer Dura
Meningeal layer
mater
Subdural space
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Pia mater
Cerebral cortex
White matter
Fig. 15.4
Cranial meninges
• epidural space is potential
space between dura mater
and bones
• subdural space is potential
space under dura mater
Skin of scalp
Periosteum
Bone of skull
Periosteal layer Dura
Meningeal layer
mater
Subdural space
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Pia mater
Cerebral cortex
White matter
Fig. 15.4
Cranial meninges
• Arachnoid mater
(AKA arachnoid membrane)
• external to pia mater
• resembles spider web
• composed of collagen and
elastic fibers called arachnoid
trebeculae
• subarachnoid space filled with
trebeculae
Skin of scalp
Periosteum
Bone of skull
Periosteal layer
Dura
Meningeal layer mater
Subdural space
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Pia mater
Cerebral cortex
White matter
Fig. 15.4
Cranial meninges
• Pia mater
pia = tender; mater = mother
• deepest meningeal layer
• areolar connective tissue
• highly vascularized
• sticks to brain
Skin of scalp
Periosteum
Bone of skull
Periosteal layer Dura mater
Meningeal layer
Subdural space
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Pia mater
Cerebral cortex
White matter
Fig. 15.5
Cranial Dura
Septa
•
•
•
•
Dural venous sinus
(superior sagittal sinus)
Dura mater
Falx cerebri
Inferior sagittal
sinus
folds of dura mater
4 partitions of cranial cavity
stabilize brain
falx cerebri
• largest dura septa
• midsaggital plane; separates right and
left cerebral hemispheres
• anterior inferior attachment to crista galli of ethmoid
• posterior inferior attachment to internal occipital crest
• contains two dural venous sinuses: superior saggital sinus
and inferior saggital sinus
Dural venous
sinus
(superior
sagittal sinus)
Cranium
Fig. 15.5
Cranial Dura Septa
• falx cerebelli
• separates right and left
cerebellaral hemispheres
• contains occipital sinus in
posterior vertical border
Dura mater
Dural venous sinus
(superior sagittal sinus)
Falx cerebri
Inferior sagittal
sinus
Tentorium
cerebelli
Straight sinus
Transverse sinus
Diaphragma
sellae
Confluence
of sinuses
Pituitary
gland
Sigmoid sinus
Falx cerebelli
Occipital sinus
Occipital sinus
Cranium
Fig. 15.5
Cranial Dura Septa
• tentorium cerebelli
Dura mater
Dural venous sinus
(superior sagittal sinus)
Falx cerebri
Inferior sagittal
sinus
• horizontal fold of dura
mater
Tentorium
• separates occipital and
cerebelli
Diaphragma
temporal lobes from
sellae
cerebellum
Pituitary
• contains transverse sinuses
gland
in posterior border
• anterior border has
tentorial notch; brain stem
passes through
Straight sinus
Transverse
sinus
Sigmoid sinus
Falx cerebelli
Occipital sinus
Transverse sinus
Cranium
Fig. 15.5
Cranial Dura Septa
• diaphragma sellae
Dura mater
Dural venous sinus
(superior sagittal sinus)
Falx cerebri
Inferior sagittal
sinus
• smallest dura septa
• form roof over sella turica of Tentorium
cerebelli
sphenoid bone
• infundibulum passes
Diaphragma
through; pituitary gland sellae
hangs from infundibulum
Straight sinus
Transverse sinus
Confluence
of sinuses
Sigmoid sinus
Falx cerebelli
Occipital sinus
Pituitary
gland
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Fig. 15.5
Cranium
Dura mater
Dural venous sinus
(superior sagittal sinus)
Falx cerebri
Inferior sagittal
sinus
Tentorium
cerebelli
Straight
sinus
Transverse
sinus
Diaphragma
sellae
Confluence
of sinuses
Pituitary
gland
Sigmoid sinus
Falx cerebelli
Occipital sinus
Cranium
Dura mater
Falx cerebri
Dural venous sinus
(superior sagittal sinus)
Inferior sagittal sinus
Diaphragma sellae
Pituitary gland
Straight sinus
Tentorium cerebelli
Tentorial notch
Transverse sinus
Confluence of sinuses
Falx cerebelli
Occipital sinus
Brainstem
Midsagittal section
© The McGraw-Hill Companies, Inc./Photos and Dissections by Christine Eckel
Posterior view
Fig. 15.6
Brain Ventricles
• 4 cavities in brain,
connected to each
other and central canal
of spinal cord
• Make and contain
cerebrospinal fluid
Posterior
Third
ventricle
Anterior
Interventricular foramen
Lateral ventricles
Cerebral aqueduct
Fourth
ventricle
Lateral aperture
Median aperture
Central canal
of spinal cord
(a) Lateral view
Posterior
Third
ventricle
Anterior
Interventricular
foramen
Lateral
ventricles
Cerebrum
Lateral ventricle
Interventricular
foramen
Third ventricle
Cerebral
aqueduct
Cerebral
aqueduct
Fourth
ventricle
Fourth ventricle
Lateral aperture
Median aperture
Central canal
of spinal cord
(a) Lateral view
Central canal
of spinal cord
(b) Anterior view
Cerebrospinal Fluid
• clear, colorless liquid
• bathes surfaces of CNS
• brain floats in CSF, preventing it from being crushed under its own
weight
• cushions brain during sudden movements
• transports nutrients and chemicals to brain; removes waste from
brain
• formed by choroid plexus in each ventricle
Fig. 15.7
Corpus
callosum
Ependymal
Longitudinal fissure cells
Choroid plexus
in lateral ventricles
Capillary
Pia
mater
Cavity of ventricle
(a) Coronal section of the brain, close-up
(b) Choroid plexus
Choroid plexus
• Blood plasma secreted
through ependymal
cells
• ependymal cells
secrete CSF
• CSF circulates through
ventricles, enters
subarachnoid space,
removed from
subarachnoid space
Fig. 15.8
Dural venous sinus
(superior sagittal sinus)
Pia mater
Choroid plexus
1. CSF is
produced by the
choroid plexus in
the ventricles.
5
4
Interventricular
foramen
CSF flow
Lateral aperture
Arachnoid villi
Venous
fluid flow
1
2
3
Choroid plexus
of fourth ventricle
Median aperture
Cerebral
aqueduct
Dura mater
Subarachnoid space
Central canal of spinal cord
(a) Midsagittal section
Fig. 15.8
Dural venous sinus
(superior sagittal sinus)
Pia mater
Choroid plexus
2. CSF flows from the
third ventricle through
the cerebral aqueduct
into the fourth ventricle.
5
4
Interventricular
foramen
CSF flow
Lateral aperture
Arachnoid villi
Venous
fluid flow
1
2
3
Choroid plexus
of fourth ventricle
Median aperture
Cerebral
aqueduct
Dura mater
Subarachnoid space
Central canal of spinal cord
(a) Midsagittal section
Fig. 15.8
Dural venous sinus
(superior sagittal sinus)
Pia mater
Choroid plexus
3. CSF in the fourth
ventricle flows into the
subarachnoid space by
passing through the
paired lateral apertures
or the single median
aperture, and into the
central canal of the spinal
cord.
5
4
Interventricular
foramen
CSF flow
Lateral aperture
Arachnoid villi
Venous
fluid flow
1
2
3
Choroid plexus
of fourth ventricle
Median aperture
Cerebral
aqueduct
Dura mater
Subarachnoid space
Central canal of spinal cord
(a) Midsagittal section
Fig. 15.8
Dural venous sinus
(superior sagittal sinus)
Pia mater
Choroid plexus
5
4
1
Arachnoid villi
Venous
fluid flow
Interventricular
foramen
4. As the CSF flows
CSF flow
through the subarachnoid
2
Lateral
aperture
space, it removes waste
products and provides
3
Choroid plexus
buoyancy to support the
of fourth ventricle
brain.
Median aperture
Cerebral
aqueduct
Dura mater
Subarachnoid space
Central canal of spinal cord
(a) Midsagittal section
Fig. 15.8
Dural venous sinus
(superior sagittal sinus)
Pia mater
Choroid plexus
5
4
Interventricular
foramen
CSF flow
Lateral aperture
5. Excess CSF flows into
arachnoid villi, then drains into
the dural venous sinuses. The
greater pressure on the CSF in
the subarachnoid space ensures
that CSF moves into the venous
sinuses without permitting
venous blood to enter the
subarachnoid space.
Arachnoid villi
Venous
fluid flow
1
2
3
Choroid plexus
of fourth ventricle
Median aperture
Cerebral
aqueduct
Dura mater
Subarachnoid space
Central canal of spinal cord
(a) Midsagittal section
Fig. 15.8
Arachnoid
Superior
villus
sagittal sinus
Dura mater
(meningeal layer)
Arachnoid mater
Subarachnoid space
Pia mater
CSF
flow
Arachnoid villi
5
Dural venous sinus
(superior sagittal sinus)
Pia mater
Dura
Choroid plexus
mater
(periosteal
layer) Interventricular foramen
4
Venous
fluid flow
1
(b) Arachnoid villus
1. CSF is produced by the choroid plexus in the ventricles.
2. CSF flows from the third ventricle through the
cerebral aqueduct into the fourth ventricle.
3. CSF in the fourth ventricle flows into the subarachnoid
space by passing through the paired lateral apertures
or the single median aperture, and into the central canal
of the spinal cord.
CSF flow
Cerebral aqueduct
Lateral aperture
Choroid plexus
of fourth ventricle
2
3
Dura mater
Median aperture
Subarachnoid space
Central canal of spinal cord
4. As the CSF flows through the subarachnoid space, it
removes waste products and provides buoyancy to
support the brain.
5. Excess CSF flows into arachnoid villi, then drains into
the dural venous sinuses. The greater pressure on the
CSF in the subarachnoid space ensures that CSF moves
into the venous sinuses without permitting venous blood
to enter the subarachnoid space.
(a) Midsagittal section
Blood-Brain Barrier
• perivascular feet of astrocytes are
external layer
Astrocyte
Nucleus
Fig. 15.9
Perivascular feet
• tight junctions between cells of
capillaries prevent movement of
unwanted materials
Erythrocyte
inside
• continuous basement membrane
capillary
is 3rd layer
• lipid-soluble compounds can
diffuse through plasma membrane
and enter brain (nicotine, alcohol,
some anesthetics, etc.)
Capillary
Continuous basement membrane
Tight junction between
endothelial cells
Nucleus of endothelial cell
Cerebral Hemispheres
Left cerebral Right cerebral
hemisphere hemisphere
Anterior
Frontal lobes
Parietal lobes
Occipital lobes
• Left and right hemispheres separated by
longitudinal fissure along midsaggital
plane
Gyrus
Sulcus
• hemispheres almost completely separate
• communication between hemispheres
through tracts, bundles of axons
Precentral gyrus
Central sulcus
• corpus callosum is largest
Postcentral gyrus
Longitudinal
fissure
Superior view
Fig. 15.10
Posterior
Cerebral Lobes
Left cerebral Right cerebral
hemisphere hemisphere
Anterior
Frontal lobes
Parietal lobes
Occipital lobes
• five lobes per hemisphere
• frontal lobe ends at central sulcus and lateral
sulcus on inferior side
• concerned with voluntary motor
functions, concentration, verbal
communication, decision making,
planning, personality
• precentral gyrus is mass of nervous
tissue anterior to central sulcus
• parietal
• temporal
• occipital
• insula (not visible at surface)
Gyrus
Sulcus
Precentral gyrus
Central sulcus
Postcentral gyrus
Longitudinal
fissure
Superior view
Posterior
Cerebral Lobes
Left cerebral Right cerebral
hemisphere hemisphere
Anterior
Frontal lobes
Parietal lobes
Occipital lobes
• five lobes per hemisphere
• parietal lobe bordered by central sulcus,
longitudinal fissure, and parieto-occipital
sulcus
• involved with general sensory functions
(ex. evaluating shape and texture of
objects being touched)
• temporal lobe is inferior to lateral sulcus
• involved with hearing and smell
Gyrus
Sulcus
Precentral gyrus
Central sulcus
Postcentral gyrus
Longitudinal
fissure
Superior view
Posterior
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Cerebral Lobes
Left cerebral Right cerebral
hemisphere hemisphere
Anterior
Frontal lobes
Parietal lobes
Occipital lobes
• five lobes per hemisphere
• occipital lobe
• resonsible for processing incoming
visual information and storing visual
memories
• insula (not visible at surface)
• deep to lateral sulcus
• probably involved in interoceptive
awareness, emotional responses,
empathy, and interpretation of taste
Gyrus
Sulcus
Precentral gyrus
Central sulcus
Postcentral gyrus
Longitudinal
fissure
Superior view
Posterior
Fig. 15.11
Frontal lobe (retracted)
Primary motor cortex
(in precentral gyrus)
Central sulcus
Premotor cortex
Parietal lobe
Primary somatosensory cortex
(in postcentral gyrus)
Somatosensory association area
Frontal eye field
Motor speech area
(Broca area)
Parieto-occipital sulcus
Wernicke area
Insula
Primary
gustatory
cortex
Gnostic
area
Lateral
sulcus
Temporal lobe (retracted)
Primary auditory cortex
Auditory association area
Primary olfactory cortex
Occipital lobe
Primary visual cortex
Visual association area
Primary motor cortex
(within precentral gyrus)
Trunk
Hip
Leg
Foot
Hip
Knee
Trunk
Neck
Primary somatosensory cortex
(within postcentral gyrus)
Toes
Ankle
Genitals
Toes
Pharynx
Intra-abdominal
Lateral
Medial
Primary somatosensory cortex
Medial
Lateral
Primary motor cortex
Fig. 15.12
How do we learn what different parts of the
brain do?
• Study people who have had brain injuries
• Ex. Phineas Gage
• railroad construction worker
• injured Sept. 1848: tamping rod (13 pounds, 3.5 feet long) went through his
head
Page 457
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Computer reconstructions of Phineas Gage’s skull injury.
Dornsife Neuroscience Imaging Center and Brain and Creativity Institute, University of Southern California. H. Damasio et al., “The return of Phineas Gage: Clues about the
brain from the skull of a famous patient,” Science, 264(5162):1102-1105 © 1994 American Association for the Advancement of Science
• Gage’s personality changed after he
recuperated
• became irreverent and profane, incapable
of making decisions
• Research into his case led to understanding of
working of frontal lobe
Other cases
• Rep. Gabrielle Giffords
• Shot while talking to constituents
• Bullet entered left side of forehead,
exited at back of left side of head
• After recovery, can understand language,
but has difficulty speaking clearly
• Dr. John Hamdi, retired professor of chemistry
• suffered a skull fracture during a skiing accident, then a stroke
• paralysis on the right side of the body
• inability to speak properly
• took great effort to say “I want water.”
• “Dr. Hamdi could convey the general sense of what he was trying to say, but his speech
was slow and effortful, conveyed in a flat monotone, filled with pauses, and almost
completely devoid of [grammatical structure].”
• Writing also had bad grammatical structure
• Could sing perfectly well, without missing any words
From The Tell-Tale Brain by V.S. Ramachandran
Fig. 15.11
Frontal lobe (retracted)
Primary motor cortex
(in precentral gyrus)
Central sulcus
Premotor cortex
Parietal lobe
Primary somatosensory cortex
(in postcentral gyrus)
Somatosensory association area
Frontal eye field
Motor speech area
(Broca area)
Parieto-occipital sulcus
Wernicke area
Insula
Primary
gustatory
cortex
Gnostic
area
Lateral
sulcus
Temporal lobe (retracted)
Primary auditory cortex
Auditory association area
Primary olfactory cortex
Occipital lobe
Primary visual cortex
Visual association area
Functional areas of the cerebrum
• Primary motor cortex (AKA somatic motor area)
• controls voluntary skeletal muscle activity
• neurons cross to the opposite side of brainstem and
spinal cord
• left primary motor cortex controls right side of body
• information processed in premotor cortex (AKA somatic motor association
area) anterior to primary motor cortex
• coordinates learned, skilled motor activities (moving eyes while reading)
• Frontal eye field
• superior surface of middle frontal gyrus
• control and regulate eye movement for reading, and coordinating binocular vision
• Sometimes considered part of motor cortex
Page 469
Frontal Lobotomy
• Introduced as “cure” for mental
disturbances, especially violence
• 1936 by Portuguese neurologist Egas Moniz
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Prefrontal
cortex
• no existing treatments except heavy
sedation, physical restraint
• Destroyed connections between
prefrontal areas and rest of brain
• Moniz earned Nobel prize in 1949
• Procedure became overused, had
serious side effects; was not effective on
many patients
Needle
probe
Orbit
Functional areas of the cerebrum
• Motor speech area (AKA Broca area)
• interolateral portion of left frontal lobe
• responsible for controlling muscular movements for speaking
• Wernicke area
• overlaps parietal and occipital lobes on left hemisphere
• association area involved in recognizing, understanding and comprehending
spoken or written language
Functional areas of the cerebrum
• Primary somatosensory cortex
• located in postcentral gyrus of parietal lobes
• receives somatic sensory information (touch, pressure,
pain, temperature)
somatosensory association area
• Somatosensory association area located posterior to somatosensory
cortex
• interprets sensory information
• integrates sensations to determine texture, temperature, pressure, shape
Functional areas of the cerebrum
• Primary visual cortex
• receives and processes incoming visual information
• Primary auditory cortex
• receives and processes incoming auditory information
• Primary gustatory cortex
• located in insula
• processes taste information
• Primary olfactory cortex
• provides conscious awareness of smells
somatosensory association area
Functional areas of the cerebrum
• Visual association area
• located in occipital lobe
• surrounds primary visual area
• enables processing of visual information
• analyze color, movement, and form to identify
what it is we are seeing
• integrates disparate shapes and colors into a
single things (such as a face)
visual
cortex
visual
association area
Functional areas of the cerebrum
• Gnostic area
• covers regions of parietal occipital, and temporal lobes
• integrates sensory, visual, and auditory information
• provides comprehensive understanding of complex sets of stimuli
Fig. 15.11
Frontal lobe (retracted)
Primary motor cortex
(in precentral gyrus)
Central sulcus
Premotor cortex
Parietal lobe
Primary somatosensory cortex
(in postcentral gyrus)
Somatosensory association area
Frontal eye field
Motor speech area
(Broca area)
Parieto-occipital sulcus
Wernicke area
Insula
Primary
gustatory
cortex
Gnostic
area
Lateral
sulcus
Temporal lobe (retracted)
Primary auditory cortex
Auditory association area
Primary olfactory cortex
Occipital lobe
Primary visual cortex
Visual association area
What does that tell us?
• If someone can understand language but not speak properly (Gabby
Giffords and Dr. Hamdi) where is the damage?
• What areas are not damaged?
Fig. 15.13
Arcuate fibers
(a) Sagittal view
Association Tracts
Corpus callosum
Longitudinal
fasciculi
Parietal lobe
Longitudinal fissure
Cortex
Frontal lobe
Temporal lobe
Occipital lobe
• groups of axons with similar
function
• connect different regions of
same hemisphere
Commissural tracts
(in corpus callosum)
Cerebral
nuclei
Lateral ventricle
Thalamus
Lateral
sulcus
Third ventricle
Projection
tracts
Pons
Decussation
in pyramids
Medulla oblongata
(b) Coronal section
Fig. 15.13
Arcuate fibers
Longitudinal
fasciculi
(a) Sagittal view
Corpus callosum
• Arcuate fibers are short and
connect neighboring gyri in
same hemisphere
• ex. tract connects primary motor
cortex to motor association area
Frontal lobe
Temporal lobe
• Longer association tracts are
composed of longitudinal
fasciculi; connect gyri in
different lobes of same
hemisphere
• ex. tract connects Wernicke area
to motor speech (Broca) area
Fig. 15.13
• Commissural tracts
connect two
hemispheres
• commissure =
axonal bridge
• ex. Corpus callosum
Longitudinal fissure
Cortex
Commissural tracts
(in corpus callosum)
Cerebral
nuclei
Lateral
sulcus
Lateral ventricle
Thalamus
Third ventricle
Projection
tracts
Decussation
in pyramids
Pons
Medulla oblongata
(b) Coronal section
Fig. 15.13
• Projection tracts link
cerebral cortex to
inferior brain regions
and spinal cord
Longitudinal fissure
Cortex
Commissural tracts
(in corpus callosum)
Cerebral
nuclei
Lateral
sulcus
Lateral ventricle
Thalamus
Third ventricle
Projection
tracts
Decussation
in pyramids
Pons
Medulla oblongata
(b) Coronal section
Fig. 15.15
Diencephalon
Diencephalon
Corpus
callosum
Fornix
Septum
pellucidum
Choroid plexus in 3rd ventricle
Habenular nucleus
EpithalPineal gland
amus
Posterior commissure
Interthalamic
adhesion
Anterior
commissure
Tectal plate
Midsagittal section
Diencephalon
• Sandwiched between inferior
regions of cerebral hemispheres
Diencephalon
• Epithalamus
• includes pineal gland (secretes
melatonin, regulates circadian
rhythm)
Diencephalon
• Thalamus
• made of 12 thalamic nuclei
• axons from nuclei project into regions
of cerebral cortex
• impulses from all conscious senses
except olfaction converge on
thalamus, relayed to the primary
somatosensory cortex
Diencephalon
• Hypothalamus
• Master control of autonomic
nervous system and endocrine
system (hormones)
• Regulation of body temperature
• Control of emotional behavior, and
food and water intake
• Regulation of circadian (sleep-wake)
rhythms
Fig. 15.18
Diencephalon
Thalamus
Pineal gland
Superior
colliculi
Thalamus
Diencephalon
Optic chiasm
Infundibulum
Mammillary bodies
Tectal
Midbrain plate
Inferior
colliculi
Optic tract
Cerebral peduncle
Superior cerebellar peduncle
Midbrain
Optic tract
Middle cerebellar peduncle
Pons
Cranial
nerves
Inferior cerebellar peduncle
Pons
Brainstem
Pyramids
Olive
Decussation of
the pyramids
Medulla
oblongata
Medulla
oblongata
Fourth ventricle
Olive
Nucleus cuneatus
Nucleus gracilis
(b) Posterolateral view
(a) Anterior view
Fig. 15.18
Midbrain
Diencephalon
Thalamus
Pineal gland
• somatic motor
axons pass through
from primary motor
Superior
cortex to spinal cord Midbrain
colliculi
Tectal
• integrates information from
Inferior
plate
cerebrum and cerebellum
colliculi
• controls involuntary
movement of erector spinae
Pons
muscles
• produce neurotransmitter
dopamine
Medulla
oblongata
Optic tract
Cerebral peduncle
Superior cerebellar peduncle
Middle cerebellar peduncle
Inferior cerebellar peduncle
Fourth ventricle
Olive
Nucleus cuneatus
Nucleus gracilis
(b) Posterolateral view
Fig. 15.19
Midbrain
• substantia nigra
houses clusters of
Tectum
neurons that
• affects movement, Tegmentum
emotional
response, ability
to experience
pleasure and pain
• degeneration
causes Parkinson’s
disease
Posterior
Superior colliculus
Cerebral aqueduct
Reticular formation
Periaqueductal gray matter
Nucleus for oculomotor nerv
Medial lemniscus
Red nucleus
Substantia nigra
Cerebral peduncle
Oculomotor nerve (CN III)
Anterior
Midbrain, cross-sectional view
Page 470
Boxer Muhammad Ali and actor Michael J. Fox are two famous
Parkinson disease patients.
© Kenneth Lambert/AP Photo
Fig. 15.18
Midbrain
• Tectum = tectal plate
• contains sensory nuclei
• superior colliculi are visual reflex
center; help visually track moving
objects and control reflexes in
response to visual stimulus
• inferior colliculi are auditory
reflex centers; control reflexive
response to sound
Diencephalon
Thalamus
Pineal gland
Superior
colliculi
Midbrain
Tectal Inferior
plate colliculi
Pons
Medulla
oblongata
(b) Posterolateral view
Fig. 15.18
Diencephalon
Pons
• Contains sensory and motor tracts
that connect brain to spinal cord
• helps regulate breathing
Pineal gland
Superior
colliculi
Midbrain
Tectal
plate
Inferior
colliculi
Pons
Medulla
oblongata
(b) Posterolateral view
Fig. 15.21
Medulla oblongata
• Continuous with spinal cord
• All communication between brain and
spinal cord goes through medulla
• Pyramids hold corticospinal
(pyramidal) tracts
• some cross to opposite side of
brain at decussation of the
pyramids
• Olives relay sensory impulses to
cerebellum, especially proprioceptive
information
Posterior
Fourth ventricle
Olive
Pyramid
Inferior
olivary
nucleus
Decussation
of pyramids
Spinal cord
Anterior
(a) Medulla oblongata, cross-sectional view
(a) Midsagittal section
Fig. 15.22
Cerebral
aqueduct
Cerebellum
• convoluted surface covered by cerebellar
cortex
Midbrain
• folia = folds in cerebellum
• arbor vitae = white matter
Fourth ventricle
• functions:
Pons
• fine-tunes and coordinates skeletal
muscle movements
• enables precise, smooth movements
Medulla
• maintains posture and equilibrium
oblongata
Tectal plate
White matter
(arbor vitae)
Folia
Gray matter
Fig. 15.22
Cerebellum
• two cerebellar hemispheres
• anterior lobe and posterior lobe
separated by primary fissure
• vermis is narrow band of cortex
• separates hemispheres
• helps maintain balance
Anterior
Cerebellar
hemisphere
Primary
fissure
Anterior lobe
Vermis
Posterior
lobe
Folia
Posterior
(b) Cerebellum, superior view
Fig. 15.23
Corpus callosum Anterior commissure
Limbic System
• Includes structures from
cerebrum and diencephalon
• Processes and experiences
emotion
• motivation
• emotion
Olfactory bulb Olfactory tract
• emotional memory
Midsagittal section
Cingulate gyrus
Fornix
Ant. thalamic nucleus
Septal nucleus
Mammillary body
Hippocampus
Amygdaloid body
Parahippocampal gyrus
Fig. 15.23
Corpus callosum Anterior commissure
Cingulate gyrus
Fornix
Ant. thalamic nucleus
Septal nucleus
Limbic System
• Cingulate gyrus = cerebral
cortex within longitudinal
fissure
• receives input from rest of
limbic system, focuses
attention
Olfactory bulb
Midsagittal section
Mammillary body
Hippocampus
Amygdaloid body
Olfactory tract
Parahippocampal gyrus
Fig. 15.23
Corpus callosum Anterior commissure
Cingulate gyrus
Fornix
Ant. thalamic nucleus
Septal nucleus
Limbic System
• Parahippocampal gyrus =
cortical tissue in temporal lobe
Mammillary body
Hippocampus
• works with hippocampus
• Hippocampus stores memories,
forms long-term memories
• Fornix connects hippocampus
with other limbic structures Olfactory bulb
Midsagittal section
Amygdaloid body
Olfactory tract
Parahippocampal gyrus
Fig. 15.23
Corpus callosum Anterior commissure
Limbic System
• Amygdaloid body involved with
emotion, especially fear
• codes and stores memories
based on emotion
• olfactory bulbs, tracts, and
cortex process odor sensation
Olfactory bulb Olfactory tract
Midsagittal section
Cingulate gyrus
Fornix
Ant. thalamic nucleus
Septal nucleus
Mammillary body
Hippocampus
Amygdaloid body
Parahippocampal gyrus
Fig. 15.24
Cranial nerves
Cranial Nerves
Olfactory bulb, termination
of olfactory nerve (CN I)
Olfactory tract
Optic chiasm
Optic nerve (CN II)
Infundibulum
Optic tract
Oculomotor nerve (CN III)
Trochlear nerve (CN IV)
Pons
Trigeminal nerve (CN V)
Abducens nerve (CN VI)
Facial nerve (CN VII)
Vestibulocochlear nerve (CN VIII)
Medulla
oblongata
Glossopharyngeal nerve (CN IX)
Vagus nerve (CN X)
Hypoglossal nerve (CN XII)
Accessory nerve (CN XI)
Spinal cord
• Originate on inferior surface of brain
• Part of peripheral nervous system (PNS)
• Numbered starting with most anterior
Fig. 15.24
Cranial nerves
Cranial Nerves
Olfactory bulb, termination
of olfactory nerve (CN I)
Olfactory tract
Optic chiasm
Optic nerve (CN II)
Infundibulum
Optic tract
Oculomotor nerve (CN III)
Trochlear nerve (CN IV)
Pons
Trigeminal nerve (CN V)
Abducens nerve (CN VI)
Facial nerve (CN VII)
Vestibulocochlear nerve (CN VIII)
Medulla
oblongata
Glossopharyngeal nerve (CN IX)
Vagus nerve (CN X)
Hypoglossal nerve (CN XII)
Accessory nerve (CN XI)
Spinal cord
• Some are motor only
•
•
•
•
•
oculomotor (CN III)
trochlear (CN IV)
abducens (CN VI)
accessory (CN II)
hypoglossal (CN XII)
• Some are sensory only
• olfactory (CN I)
• optic (CN II)
• vestibulocochlear (CN VIII)
• Some carry both signals
•
•
•
•
trigeminal (CN V)
facial (CN VII)
glossopharyngeal (CN IX)
vagus (CN X)
Fig. 15.24
Cranial nerves
Cranial Nerves
Olfactory bulb, termination
of olfactory nerve (CN I)
• Mnemonics
Olfactory tract
Optic chiasm
Optic nerve (CN II)
Infundibulum
Optic tract
Oculomotor nerve (CN III)
Trochlear nerve (CN IV)
Pons
Trigeminal nerve (CN V)
Abducens nerve (CN VI)
Facial nerve (CN VII)
Vestibulocochlear nerve (CN VIII)
Medulla
oblongata
Glossopharyngeal nerve (CN IX)
Vagus nerve (CN X)
Accessory nerve (CN XI)
Hypoglossal nerve (CN XII)
Spinal cord
•
•
•
•
•
•
•
•
•
•
•
•
On
Occasion
Our
Trusty
Truck
Acts
Funny
Very
Good
Vehicle
Any
How
• for function:
•
•
•
•
•
•
•
•
•
•
•
•
Oh
Once
One
Takes
The
Anatomy
Final
Very
Good
Vacations
Are
Heavenly
•
•
•
•
•
•
•
•
•
•
•
•
Some
Say
Marry
Money
But
My
Brother
Says
Big
Brains
Matter
More
Table 15.8a
Olfactory Nerve (CN I)
Olfactory tract
(to cerebral cortex) Olfactory bulb
Cribriform plate
of ethmoid bone
• Senses smell
Axons of olfactory
nerves (CN I)
Optic Nerve (CNII)
• Vision from lateral side of
eye travels to same side of
visual cortex
• Vision from medial side of
eye crosses in optic chiasm,
travels to opposite side of
visual cortex
Eye
Table 15.8a-4
Optic nerve (CN II)
Optic chiasm
Optic tract
Lateral geniculate
nucleus of thalamus
Optic projection axons
Visual cortex (in occipital lobe)
Oculomotor Nerve (CNII)
• Innervates upper
eyelid muscleand
4 of 6 extrinsic eye
muscles
•
•
•
•
Medial rectus
Medial rectus
Inferior rectus
Oculomotor
Inferior oblique nerve (CN III)
Levator
Ciliary ganglion
palpebrae
Inferior rectus
superioris
Inferior oblique
• Superior rectus
Levator palpebrae
superioris Optic
nerve
Superior
rectus
To ciliary
muscles
To sphincter
pupillae
Trochlear CNIV
• Controls movement of
superior oblique eye muscle
Optic
nerve (CN II)
Trochlear nerve (CN IV)
Superior
oblique
Table 15.8c
CN V Trigeminal Nerve
Ophthalmic branch (V1)
Trigeminal nerve
Ophthalmic branch (V1)
Maxillary branch (V2)
Mandibular branch (V3)
Trigeminal ganglion
Trigeminal nerve
(CN V)
Mandibular
branch (V3)
Chorda tympani
(from facial nerve)
Maxillary
branch (V2)
Superior
alveolar
nerves
To muscles
of mastication
Lingual nerve
Sensory distribution
of trigeminal nerve
Inferior alveolar nerve
Submandibular
ganglion
To mylohyoid muscle
Mental nerve
Primary functions:
• controls muscles of mastication
• receives sensation from face
Abducens Nerve CN VI
• Innervates lateral rectus eye
muscle
Lateral rectus (cut)
Abducens nerve (CN VI)
Optic nerve
Facial Nerve CN VII
Geniculate ganglion
Pons
Facial nerve (CN VII)
Posterior auricular branch
Stylomastoid foramen
Parotid gland
Branch of lingual nerve of CN V
Cervical branch
• Innervates muscles of facial expression, lacrimal gland, salivary
glands
• Conducts taste from anterior 2/3 of tongue
Temporal branch
Lacrimal gland
Greater petrosal nerve
Pterygopalatine ganglion
Zygomatic branch
Chorda tympani nerve
(traveling to mandibular
branch of CN V)
Buccal branch
Submandibular ganglion
Mandibular branch
Vestibulocochlear Nerve
Vestibular branch
Semicircular canals
CN VIII
Internal acoustic meatus
Vestibulocochlear
nerve (CN VIII)
• Conducts equilibrium and
auditory information from
inner ear to brain
• Originates in vestibular
nerve and cochlear nerve
within middle ear
Pons
Medulla
oblongata
Cochlea
Cochlear branch
Glossopharyngeal Nerve CN IX
• Receives taste and touch
sensation from posterior
tongue
• Innervates one pharynx
muscle and parotid
salivary gland
Superior ganglion
Otic ganglion
To parotid gland
Inferior ganglion
Glossopharyngeal
nerve (CN IX)
To stylopharyngeus
muscle
To carotid body
and carotid sinus
To posterior 1/3
of tongue for taste
and general sensation
Table 15.8f-2
CN X Vagus Nerve
Superior ganglion
Inferior ganglion
Pharyngeal branch
• Visceral sensory information
from most internal organs
Right vagus nerve (CN X)
• Control of pharynx and
larynx muscles
• Control of smooth and
cardiac muscle
• Innervates glands, lungs, etc.
Superior laryngeal nerve
Internal laryngeal nerve
External laryngeal nerve
Left vagus nerve (CN X)
Right recurrent
laryngeal branch
Left recurrent
laryngeal branch
Cardiac branch
Lung
Pulmonary plexus
Heart
Anterior vagal trunk
(formed from left vagus)
Kidney
Spleen
Liver
Stomach
Pancreas
Small intestine
Ascending
colon
Appendix
Accessory Nerve CN XI
• Innervates trapezius,
sternocleidomastoid, and
other pharynx muscles
Cervical region of
spinal cord (C1–C5)
Accessory nerve (CN XI)
Sternocleidomastoid muscle
Trapezius muscle
Hypoglossal Nerve CN XII
Hypoglossal
nerve (CN XII)
• Innervates intrinsic and
extrinsic tongue muscles
C1
C2
C3
Ansa cervicalis to
infrahyoid muscles
(cervical nerves
running with
hypoglossal)
To tongue muscles
To geniohyoid muscle