Download Occipital lobe

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
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
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
Table 15.1
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
Skin of scalp
Periosteum
Bone of skull
Arachnoid
granulation
Periosteal layer
Meningeal layer
Subdural space (potential space)
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Dural venous
sinus (superior
sagittal sinus)
• Pia mater
pia = tender; mater = mother
• deepest meningeal layer
• areolar connective tissue
• highly vascularized
• sticks to brain
Dura mater
Pia mater
Cerebral cortex
White matter
Falx cerebri
Fig. 15.4
Cranial meninges
Skin of scalp
Periosteum
Bone of skull
Arachnoid
granulation
Dural venous
sinus (superior
sagittal sinus)
• Arachnoid mater
(AKA arachnoid membrane)
Falx cerebri
• external to pia mater
• resembles spider web
• composed of collagen and elastic fibers called arachnoid trebeculae
• subarachnoid space filled with trebeculae
Periosteal layer
Meningeal layer
Dura mater
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Cerebral cortex
White matter
Fig. 15.4
Cranial meninges
• Dura mater
Arachnoid
dura = tough
granulation
• dense,
Dural venous
irregular
sinus (superior
sagittal sinus)
connective
tissue
• meningeal layer deep to
periosteal layer (layers usually
Falx cerebri
fused together)
• where not fused, dural venous sinuses form; large veins that
drain blood from brain
• epidural space and subdural space are potential spaces
between dura mater and bones
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
Cranium
Dura mater
Fig. 15.5
Cranial Dura Septa
•
•
•
•
Dural venous sinus
(superior sagittal sinus)
Inferior sagittal
sinus
folds of dura mater
4 partitions of cranial cavity
stabilize brain
falx cerebri
Falx cerebri
Tentorium
cerebelli
Straight sinus
Transverse sinus
Diaphragma
sellae
Confluence
of sinuses
Pituitary
gland
• 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
Sigmoid sinus
Falx cerebelli
Occipital 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
Tentorium
mater
cerebelli
• separates occipital and
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
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
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
Third
ventricle
Fourth
entricle
Posterior
Anterior
Interventricular
foramen
Lateral
ventricles
Cerebrum
Lateral ventricle
Interventricular
foramen
Third ventricle
Cerebral
aqueduct
Cerebral
aqueduct
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
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 is
capillary
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
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
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
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Frontal Lobotomy
• Introduced as “cure” for mental disturbances,
especially violence
• 1936 by Portuguese neurologist Egas Moniz
• 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
Prefrontal
cortex
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
(a) Sagittal view
Corpus callosum
Longitudinal
fasciculi
Parietal lobe
• 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
Occipital 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
• Projection tracts link cerebral
cortex to inferior brain regions
and spinal cord
• internal capsule is group of
axons passing to and from cortex
between cerebral nuclei (paired,
irregular masses of gray matter)
Longitudinal fissure
Cortex
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. 15.14
• Caudate nucleus
• produce pattern
and rhythm of arms
and legs in walking
• amygdaloid body
• at tail of caudate
nucleus
• emotions, behavior,
moods
Cerebral nuclei
Caudate nucleus
Putamen
Globus
pallidus
Lentiform
nucleus
Claustrum
Amygdaloid body
Corpus
striatum
Fig. 15.14
• putamen and
globus pallidus
• positioned
between insula and
and diencephalon
• together, form
lentiform nucleus
• controls muscular
movement at the
subconscious level
• claustrum
• processes visual
subconscious
information
Cerebral nuclei
Caudate nucleus
Putamen
Globus
pallidus
Lentiform
nucleus
Claustrum
Amygdaloid body
Corpus
striatum
Fig. 15.15
Corpus
callosum
Diencephalon
Septum
pellucidum
Fornix
Choroid plexus in third ventricle
Interthalamic
adhesion
Habenular nucleus
Pineal gland
Posterior commissure
Tectal plate
Anterior
commissure
Cerebral aqueduct
Fourth ventricle
Midsagittal section
Epithalamus
Diencephalon
• Sandwiched between inferior regions of
cerebral hemispheres
• Epithalamus
• includes pineal gland (secretes melatonin,
regulates circadian rhythm)
• habenular nuclei relays signals from limbic
system
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
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Fig. 15.17
Nuclei of
Hypothalamus
• Mammillary body processes
smell
• suprachiasmic nucleus
regulates sleep-wake cycle
• Arcuate nucleus regulates
appetite, release of growth
hormone
• Pituitary gland releases
hormones based on signal
from hypothalamus
Mammillary body
Suprachiasmatic
nucleus
Arcuate nucleus
Optic chiasm
Infundibulum
Posterior pituitary
Anterior pituitary
Midsagittal section of hypothalamus
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
• Cerebral aqueduct extends through
midbrain, connects 3rd and 4th
ventricles
• periaqueductal gray matter surrounds
aqueduct
• Contains nuclei of oculomotor nerve
(CN III) and trochlear nerve (CN IV)
• Cerebral peduncles = motor tracts
• somatic motor axons pass through from
primary motor cortex to spinal cord
• superior cerebellar peduncles connect
cerebellum to midbrain (stop here)
Diencephalon
Thalamus
Pineal gland
Superior
colliculi
Tectal
Midbrain plate
Inferior
colliculi
Optic tract
Cerebral peduncle
Superior cerebellar peduncle
Middle cerebellar peduncle
Pons
Inferior cerebellar peduncle
Medulla
oblongata
Fourth ventricle
Olive
Nucleus cuneatus
Nucleus gracilis
(b) Posterolateral view
Fig. 15.19
Midbrain
Posterior
• Tegmentum integrates
information from cerebrum and
cerebellum
Superior colliculus
Tectum
Cerebral aqueduct
Tegmentum
Reticular formation
Periaqueductal gray matter
Nucleus for oculomotor nerve
Medial lemniscus
• controls involuntary movement of
erector spinae muscles
• contains red nuclei and reticular
formation
Red nucleus
Substantia nigra
• substantia nigra houses clusters
of neurons that produce
dopamine (neurotransmitter)
• affects movement, emotional
response, ability to experience
pleasure and pain
• degeneration causes Parkinson’s
disease
Oculomotor nerve (CN III)
Cerebral peduncle
Anterior
Midbrain, cross-sectional view
Page 470
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Boxer Muhammad Ali and actor Michael J. Fox are two famous Parkinson
disease patients.
© Kenneth Lambert/AP Photo
Fig. 15.18
Midbrain
Diencephalon
Thalamus
Pineal gland
• Tectum 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
• four colliculi together called tectal plate
Superior
colliculi
Tectal
Midbrain plate
Inferior
colliculi
Optic tract
Cerebral peduncle
Superior cerebellar peduncle
Middle cerebellar peduncle
Pons
Inferior cerebellar peduncle
Medulla
oblongata
Fourth ventricle
Olive
Nucleus cuneatus
Nucleus gracilis
(b) Posterolateral view
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
Pons
Cranial
nerves
Inferior cerebellar peduncle
Brainstem
Pyramids
Olive
Decussation of
the pyramids
Medulla
oblongata
Middle cerebellar peduncle
Pons
Medulla
oblongata
Fourth ventricle
Olive
Nucleus cuneatus
Nucleus gracilis
(b) Posterolateral view
(a) Anterior view
Fig. 15.18
Pons
• Contains sensory and motor tracts
that connect brain to spinal cord
• middle cerebellar peduncles connect
pons to cerebellum
• helps regulate breathing, along
with pontine respiratory center
Diencephalon
Thalamus
Pineal gland
Superior
colliculi
Tectal
Midbrain plate
Inferior
colliculi
Optic tract
Cerebral peduncle
Superior cerebellar peduncle
Middle cerebellar peduncle
Pons
Inferior cerebellar peduncle
Medulla
oblongata
Fourth ventricle
Olive
Nucleus cuneatus
Nucleus gracilis
(b) Posterolateral view
Fig. 15.20
Pons
• Superior olivary nucleus receives
auditory input, helps determine
sound localization
Pontine respiratory center
Pons
Fourth
ventricle
Superior
olivary
nucleus
Medulla
oblongata
Olive
Inferior
olivary
nucleus
Reticular
formation
(a) Longitudinal section (cut-away)
Fig. 15.20
Pons
• Several sensory and motor
cranial nerve nuclei housed in
pons
• Trigeminal main sensory
nucleus and trigeminal
motor nucleus (CN V)
• Abducens (CN VI)
• Facial (CN VII)
Superior cerebellar peduncle
Posterior
Fourth ventricle
Middle cerebellar
peduncle
Trigeminal main sensory nucleus
Trigeminal motor nucleus
Reticular formation
Medial lemniscus
Superior olivary nuclei
Trigeminal nerve
Fibers of
pyramidal
tract
Pontine nuclei
Anterior
(b) Pons, cross-sectional 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
Nucleus of
vagus nerve
(CN X)
Inferior olivary
nucleus
Fourth ventricle
Nuclei of vestibulocochlear
nerve (CN VIII)
Nucleus of hypoglossal
nerve (CN XII)
Vagus nerve (CN X)
Medial lemniscus
Olive
Pyramid
Hypoglossal
nerve (CN XII)
Decussation
of pyramids
Lateral corticospinal
tract axons
Spinal nerve C1
Anterior corticospinal
tract axons
Spinal cord
Anterior
(a) Medulla oblongata, cross-sectional view
Fig. 15.21
Medulla oblongata
• Inferior cerebellar peduncles connect
medulla to cerebellum
Posterior
Nucleus of
vagus nerve
(CN X)
Inferior olivary
nucleus
Inferior cerebellar
peduncle
Fourth ventricle
Nuclei of vestibulocochlear
nerve (CN VIII)
Nucleus of hypoglossal
nerve (CN XII)
Vagus nerve (CN X)
Medial lemniscus
Olive
Pyramid
Hypoglossal
nerve (CN XII)
Decussation
of pyramids
Lateral corticospinal
tract axons
Spinal nerve C1
Anterior corticospinal
tract axons
Spinal cord
Anterior
(a) Medulla oblongata, cross-sectional view
Fig. 15.21
Medulla oblongata
• Cranial nerve nuclei
• Vestibulocochlear (CN VIII)
• Glossopharyngeal (CN IX)
• Vagus (CN X)
• Accessory (CN XI)
• Hypoglossal (CN XII)
Posterior
Nucleus of
vagus nerve
(CN X)
Inferior olivary
nucleus
Fourth ventricle
Nuclei of vestibulocochlear
nerve (CN VIII)
Nucleus of hypoglossal
nerve (CN XII)
Vagus nerve (CN X)
Medial lemniscus
Olive
Pyramid
Hypoglossal
nerve (CN XII)
Decussation
of pyramids
Lateral corticospinal
tract axons
Spinal nerve C1
Anterior corticospinal
tract axons
Spinal cord
Anterior
(a) Medulla oblongata, cross-sectional view
Fig. 15.21
Medulla oblongata
• Nucleus cuneatus and nucleus
gracilis relay sensory information to
thalamus
• Respiratory center helps control
breathing
• cardiac and vasomotor centers
control heartbeat and blood
pressure
Inferior
olivary
nucleus
Cardiac and
vasomotor
centers
Ventral
respiratory
group
Dorsal
respiratory
group
Respiratory
center
Nucleus cuneatus
Pyramid
Anterior
Nucleus gracilis
Posterior
Reticular formation
(b) Medulla oblongata, lateral view
Fig. 15.22
Cerebellum
• convoluted surface covered by cerebellar
cortex
• folia = folds in cerebellum
• arbor vitae = white matter
• functions:
• fine-tunes and coordinates skeletal muscle
movements
• enables precise, smooth movements
• maintains posture and equilibrium
Cerebral
aqueduct
Tectal plate
White matter
(arbor vitae)
Midbrain
Fourth ventricle
Pons
Medulla
oblongata
Folia
Gray matter
(a) Midsagittal section
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
Components of the limbic system
Cingulate gyrus
Limbic System
• Includes structures from
cerebrum and diencephalon
• Processes and experiences
emotion
• motivation
• emotion
• emotional memory
Fornix
Anterior thalamic nucleus
Septal nucleus
Mammillary body
Hippocampus
Amygdaloid body
Parahippocampal gyrus
Olfactory tract
Olfactory bulb
Midsagittal section
Fig. 15.23
Corpus callosum
Anterior commissure
Components of the limbic system
Cingulate gyrus
Limbic System
• Cingulate gyrus = cerebral
cortex within longitudinal
fissure
• receives input from rest of
limbic system, focuses
attention
Fornix
Anterior thalamic nucleus
Septal nucleus
Mammillary body
Hippocampus
Amygdaloid body
Parahippocampal gyrus
Olfactory tract
Olfactory bulb
Midsagittal section
Fig. 15.23
Corpus callosum
Anterior commissure
Components of the limbic system
Cingulate gyrus
Limbic System
Fornix
• Parahippocampal gyrus =
cortical tissue in temporal lobe
Anterior thalamic nucleus
Septal nucleus
Mammillary body
• works with hippocampus
• Hippocampus stores memories,
forms long-term memories
• Fornix connects hippocampus
with other limbic structures
Hippocampus
Amygdaloid body
Parahippocampal gyrus
Olfactory tract
Olfactory bulb
Midsagittal section
Fig. 15.23
Corpus callosum
Anterior commissure
Components of the limbic system
Cingulate gyrus
Limbic System
• Amygdaloid body involved with
emotion, especially fear
• codes and stores memories
based on emotion
• olfactory bulbs, tracts, and
cortex process odor sensation
Fornix
Anterior thalamic nucleus
Septal nucleus
Mammillary body
Hippocampus
Amygdaloid body
Parahippocampal gyrus
Olfactory tract
Olfactory bulb
Midsagittal section
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 15.7
Table 15.8a
Table 15.8a
Table 15.8a-4
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Eye
Optic nerve (CN II)
Optic chiasm
Optic tract
Lateral geniculate
nucleus of thalamus
Optic projection axons
Visual cortex (in occipital lobe)
Table 15.8b
Table 15.8b
Table 15.8c
CN V Trigeminal Nerve
Ophthalmic branch (V1)
Trigeminal nerve
Ophthalmic branch (V1)
Maxillary branch (V2)
Mandibular branch (V3)
Sensory distribution
of trigeminal nerve
Trigeminal ganglion
Maxillary
branch (V2)
Trigeminal nerve
(CN V)
Superior
alveolar
nerves
Mandibular
branch (V3)
To muscles
of mastication
Chorda tympani
(from facial nerve)
Lingual nerve
Inferior alveolar nerve
Submandibular
ganglion
To mylohyoid muscle
Mental nerve
Primary functions:
• controls muscles of
mastication
• sensation from face
Table 15.8d
Table 15.8d
Table 15.8d-3
CN VII Facial Nerve
Temporal branch
Geniculate ganglion
Lacrimal gland
Greater petrosal nerve
Pons
Facial nerve (CN VII)
Pterygopalatine ganglion
Zygomatic branch
Posterior auricular branch
Stylomastoid foramen
Chorda tympani nerve
(traveling to mandibular
branch of CN V)
Parotid gland
Buccal branch
Branch of lingual nerve of CN V
Submandibular ganglion
Mandibular branch
Cervical branch
Primary functions:
• controls muscles of facial expression
• sensation of taste from anterior end of tongue
Table 15.8e
Table 15.8e
Table 15.8f
Table 15.8f-2
CN X Vagus Nerve
Primary functions:
• Visceral sensory information from most
internal organs
• Control of pharynx and larynx muscles
• Control of smooth and cardiac muscle
• Innervates glands, lungs, etc.
Superior ganglion
Inferior ganglion
Pharyngeal branch
Superior laryngeal nerve
Internal laryngeal nerve
External laryngeal nerve
Right vagus nerve (CN X)
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
Table 15.8g
Table 15.8g