the adult human brain - houston community college
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© 2012 Pearson Education, Inc.
PowerPoint® Lecture Presentations prepared by
Jason LaPres
Lone Star College—North Harris
14 The Brain and Cranial Nerves
© 2012 Pearson Education, Inc.
An Introduction to the Brain and Cranial Nerves
• The Adult Human Brain
• Average weight about 1.4 kg (3 lb)
© 2012 Pearson Education, Inc.
14-1 The Brain
• Six Regions of the Brain
1. Cerebrum
2. Cerebellum
3. Diencephalon
4. Mesencephalon
5. Pons
6. Medulla oblongata
© 2012 Pearson Education, Inc.
14-1 The Brain
• Cerebrum
• Largest part of brain
• Controls higher mental functions
• Divided into left and right cerebral hemispheres
• Surface layer of gray matter (neural cortex)
© 2012 Pearson Education, Inc.
14-1 The Brain
• Cerebrum
• Neural cortex
• Also called cerebral cortex
• Folded surface increases surface area
• Elevated ridges (gyri)
• Shallow depressions (sulci)
• Deep grooves (fissures)
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14-1 The Brain
• Cerebellum
• Second largest part of brain
• Coordinates repetitive body movements
• Two hemispheres
• Covered with cerebellar cortex
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Figure 14-1 An Introduction to Brain Structures and Functions
CEREBRUM
• Conscious thought processes,
• Memory storage and processing • Conscious and subconscious regulation
of skeletal muscle contractions
intellectual functions
CEREBELLUM
• Coordinates complex somatic motor patterns
other somatic motor centers in brain and spinal cord
Fissures
Sulci
Gyri
Left cerebral
hemisphere
• Adjusts output of
Spinal cord
© 2012 Pearson Education, Inc.
14-1 The Brain
• Diencephalon
• Located under cerebrum and cerebellum
• Links cerebrum with brain stem
• Three divisions of the diencephalon
1. Left thalamus
2. Right thalamus
3. Hypothalamus
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14-1 The Brain
• Diencephalon
• Thalamus
• Relays and processes sensory information
• Hypothalamus
• Hormone production
• Emotion
• Autonomic function
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14-1 The Brain
• Diencephalon
• Pituitary gland
• Major endocrine gland
• Connected to hypothalamus
• Interfaces nervous and endocrine systems
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14-1 The Brain
• The Brain Stem
• Processes information between:
• Spinal cord and cerebrum or cerebellum
• Includes:
• Midbrain
• Pons
• Medulla oblongata
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14-1 The Brain
• Midbrain
• Also called mesencephalon
• Processes sight, sound, and associated reflexes
• Maintains consciousness
• Pons
• Connects cerebellum to brain stem
• Is involved in somatic and visceral motor control
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14-1 The Brain
• Medulla Oblongata
• Connects brain to spinal cord
• Relays information
• Regulates autonomic functions
• Heart rate, blood pressure, and digestion
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Figure 14-1 An Introduction to Brain Structures and Functions
DIENCEPHALON
THALAMUS
• Relay and processing centers for sensory
information
• Centers controlling
HYPOTHALAMUS
emotions, autonomic
functions, and
hormone production
MIDBRAIN
• Generation of reflexive
and auditory data
somatic motor responses
consciousness
PONS
MEDULLA OBLONGATA
function (cardiovascular, respiratory, and
digestive system activities)
• Relays sensory information to thalamus and to other portions of the brain stem
• Autonomic centers for regulation of visceral
Brain stem • Processing of visual
• Maintenance of
• Relays sensory information to cerebellum and thalamus • Subconscious somatic and visceral motor centers
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14-1 The Brain
• Ventricles of the Brain
• Each cerebral hemisphere contains one large lateral
ventricle
• Separated by a thin medial partition (septum
pellucidum)
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14-1 The Brain
• Ventricles of the Brain
• Third ventricle
• Ventricle of the diencephalon
• Lateral ventricles communicate with third ventricle
• Via interventricular foramen (foramen of Monro)
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14-1 The Brain
• Ventricles of the Brain
• Fourth ventricle
• Extends into medulla oblongata
• Becomes continuous with central canal of the spinal cord
• Connects with third ventricle
• Via narrow canal in midbrain called the cerebral
aqueduct
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Figure 14-2a Ventricles of the Brain
Cerebral hemispheres
Pons
Medulla oblongata
Spinal cord Central canal
Ventricular system, lateral view
Lateral ventricles
Interventricular foramen
Third ventricle
Cerebral aqueduct
Fourth ventricle
Ventricles of the Brain
© 2012 Pearson Education, Inc.
Figure 14-2b Ventricles of the Brain
Lateral ventricles
Interventricular foramen
Third ventricle
Cerebral aqueduct
Fourth ventricle
Ventricles of the Brain
Cerebral hemispheres
Central canal Cerebellum
Ventricular system, anterior view
© 2012 Pearson Education, Inc.
14-1 The Brain
• The Brain
• The brain is a large, delicate mass of neural tissue
• Containing internal passageways and chambers filled
with cerebrospinal fluid
• Each of the six major brain regions has specific
functions
• Ascending from the medulla oblongata to the cerebrum,
brain functions become more complex and variable
• Conscious thought and intelligence
• Are produced in the neural cortex of the cerebral
hemispheres
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14-2 Brain Protection and Support
• Physical Protection of the Brain
• Bones of the cranium
• Cranial meninges
• Cerebrospinal fluid
• Biochemical Isolation
• Blood–brain barrier
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14-2 Brain Protection and Support
• The Cranial Meninges
• Have three layers
1. Dura mater
2. Arachnoid mater
3. Pia mater
• Are continuous with spinal meninges
• Protect the brain from cranial trauma
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14-2 Brain Protection and Support
• The Cranial Meninges
• Dura mater
• Inner fibrous layer (meningeal layer)
• Outer fibrous layer (endosteal layer) fused to
periosteum
• Venous sinuses between two layers
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14-2 Brain Protection and Support
• The Cranial Meninges
• Arachnoid mater
• Covers brain
• Contacts epithelial layer of dura mater
• Subarachnoid space between arachnoid mater and pia mater
• Pia mater
• Attached to brain surface by astrocytes
© 2012 Pearson Education, Inc.
Figure 14-3a The Relationship among the Brain, Cranium, and Meninges
Cranium (skull)
Cerebellum
Medulla oblongata
Spinal cord
A lateral view of the brain, showing its
position in the cranium and the organization
of the meninges
Cerebral cortex
Dura mater (endosteal layer)
Dural sinus
Dura mater (meningeal layer)
Subdural space
Arachnoid mater
Subarachnoid space
Arachnoid trabeculae
Pia mater
Cerebral cortex
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14-2 Brain Protection and Support
• Cerebrospinal Fluid (CSF)
• Surrounds all exposed surfaces of CNS
• Interchanges with interstitial fluid of brain
• Functions of CSF
• Cushions delicate neural structures
• Supports brain
• Transports nutrients, chemical messengers, and waste
products
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14-2 Brain Protection and Support
• Cerebrospinal Fluid (CSF)
• Choroid plexus
• Specialized ependymal cells and capillaries
• Secrete CSF into ventricles
• Produces about 500 mL of CSF/day
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14-2 Brain Protection and Support
• Cerebrospinal Fluid (CSF)
• CSF circulates:
• From choroid plexus
• Through ventricles
• To central canal of spinal cord
• Into subarachnoid space via two lateral apertures and
one median aperture around the brain, spinal cord,
and cauda equina
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14-2 Brain Protection and Support
• Cerebrospinal Fluid (CSF)
• CSF in subarachnoid space
• Arachnoid villi
• Extensions of subarachnoid space
• Extend through dura mater to superior sagittal sinus
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Figure 14-4a The Formation and Circulation of Cerebrospinal Fluid
Choroid plexus
of third ventricle
Cerebral
aqueduct
Lateral aperture
Choroid plexus of
fourth ventricle
Arachnoid mater
Subarachnoid space
Dura mater
Filum terminale
Spinal cord
Central canal
Superior
sagittal
sinus
Extension of choroid
plexus into
lateral ventricle
Arachnoid
granulations
Median aperture
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Figure 14-4b The Formation and Circulation of Cerebrospinal Fluid
Cerebral
cortex
The relation-
ship of the
arachnoid
granulations
and dura
mater.
Pia
mater
Subarachnoid
space
Arachnoid
mater
Subdural
space
Dura mater
(meningeal
layer)
Arachnoid
trabeculae
Fluid
movement
Arachnoid
granulation
Dura mater
(endosteal
layer)
Cranium Superior
sagittal sinus
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14-2 Brain Protection and Support
• Blood Supply to the Brain
• Supplies nutrients and oxygen to brain
• Delivered by internal carotid arteries and vertebral
arteries
• Removed from dural sinuses by internal jugular veins
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Figure 21–23 Arteries of the Neck and Head
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Figure 21–24a Arteries of the Brain
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Figure 21–24b Arteries of the Brain
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Figure 21–29a Major Veins of the Head, Neck, and Brain
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Figure 21–29b Major Veins of the Head, Neck, and Brain
© 2012 Pearson Education, Inc.
Figure 21–29c Major Veins of the Head, Neck, and Brain
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14-2 Brain Protection and Support
• Cerebrovascular Disease
• Disorders interfere with blood circulation to brain
• Stroke or cerebrovascular accident (CVA)
• Shuts off blood to portion of brain
• Neurons die
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14-3 The Medulla Oblongata
• The Medulla Oblongata
• Allows brain and spinal cord to communicate
• Coordinates complex autonomic reflexes
• Controls visceral functions
• Nuclei in the Medulla
• Autonomic nuclei control visceral activities
• Sensory and motor nuclei of cranial nerves
• Relay stations along sensory and motor pathways
© 2012 Pearson Education, Inc.
Figure 14-5a The Diencephalon and Brain Stem
Cerebral peduncle
Diencephalon
Optic tract
Lateral geniculate nucleus
Midbrain
Cerebellar peduncles
Medial geniculate nucleus
Superior colliculus
Inferior colliculus
Inferior cerebellar peduncle
Middle cerebellar peduncle
Superior cerebellar peduncle
Cranial nerves
Medulla
oblongata
Thalamus
N II
N IV
N V
N VI N VII
N VIII N IX N X N XI
Pons
Spinal cord
Spinal
nerve C1
Spinal
nerve C2
Lateral view
N III
N XII
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Figure 14-5b The Diencephalon and Brain Stem
Optic chiasm
Thalamus
Pons
Optic tract
Cerebral
peduncle
Mamillary
body
Infundibulum
Cranial nerves
N II
N IV
N V
N VI
N VII
N VIII
N IX
N X
N XI
N XII
N III
Medulla oblongata
Ventral roots of spinal nerves C1 and C2
Spinal cord
Anterior view
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Figure 14-5c The Diencephalon and Brain Stem
Choroid plexus in roof
of fourth ventricle
N IV
Choroid plexus
Thalamus
Third ventricle
Pineal gland
Superior colliculi
Inferior colliculi
Inferior
Middle
Superior
Cerebellar peduncles
Corpora quadrigemina
Cerebral peduncle
Dorsal roots
of spinal nerves
C1 and C2
Posterior view
© 2012 Pearson Education, Inc.
14-3 The Medulla Oblongata
• The Medulla Oblongata
• Includes three groups of nuclei
1. Autonomic nuclei
2. Sensory and motor nuclei of cranial nerves
3. Relay stations along sensory and motor pathways
© 2012 Pearson Education, Inc.
14-3 The Medulla Oblongata
• Autonomic Nuclei of the Medulla Oblongata
• Reticular formation
• Gray matter with embedded nuclei
• Regulates autonomic functions
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14-3 The Medulla Oblongata
• Autonomic Nuclei of the Medulla Oblongata
• Reflex centers
• Control peripheral systems
• Cardiovascular centers
• Cardiac center
• Control blood flow through peripheral tissues
• Respiratory rhythmicity centers
• Set pace for respiratory movements
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14-3 The Medulla Oblongata
• Sensory and Motor Nuclei of the Medulla
Oblongata
• Associated with 5 of 12 cranial nerves (VIII, IX, X,
XI, XII)
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14-4 The Pons
• The Pons
1. Sensory and motor nuclei of cranial nerves (V, VI, VII, VIII)
2. Nuclei involved with respiration
• Apneustic center and pneumotaxic center
• Modify respiratory rhythmicity center activity
3. Nucei that process and relay information to and from
cerebellum
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Figure 14-6c The Medulla Oblongata and Pons
Tracts
Ascending tracts Descending tracts
Transverse fibers
Respiratory Centers
Pneumotaxic center
Apneustic center
Cerebellum
Fourth ventricle
Reticular formation
Medulla oblongata
Olivary nucleus
Lateral view
Midbrain
Pons
Medulla
oblongata
Spinal cord
© 2012 Pearson Education, Inc.
14-5 The Cerebellum
• Functions of the Cerebellum
1. Adjusts postural muscles
2. Fine-tunes conscious and subconscious movements
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14-5 The Cerebellum
• Structures of the Cerebellum
• Folia
• Surface of cerebellum
• Highly folded neural cortex
• Anterior and posterior lobes
• Separated by primary fissure
• Cerebellar hemispheres
• Separated at midline by vermis
© 2012 Pearson Education, Inc.
Figure 14-7a The Cerebellum
Anterior
lobe
Vermis
Primary
fissure
Right Hemisphere
of Cerebellum
Left Hemisphere
of Cerebellum
The posterior, superior surface of the cerebellum, showing
major anatomical landmarks and regions
Posterior
lobe Folia
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Figure 14-7a The Cerebellum
Left Hemisphere
of Cerebellum Right Hemisphere
of Cerebellum
Folia
Vermis
Anterior lobe
Primary fissure
Posterior lobe
The posterior, superior surface of the cerebellum,
showing major anatomical landmarks and regions
© 2012 Pearson Education, Inc.
Figure 14-7b The Cerebellum
Midbrain
Anterior lobe
Pons Cerebellar Peduncles
Superior cerebellar
peduncle
Middle cerebellar
peduncle
Inferior cerebellar
peduncle
Medulla oblongata Flocculonodular lobe
Choroid plexus of
the fourth ventricle
Posterior
lobe
Cerebellar
cortex
Cerebellar
nucleus
Arbor
vitae
A sectional view of the cerebellum, showing the arrangement of gray matter and white matter
© 2012 Pearson Education, Inc.
14-6 The Midbrain
• Structures of the Midbrain
• Tectum
• Two pairs of sensory nuclei (corpora quadrigemina)
• Superior colliculus (visual)
• Inferior colliculus (auditory)
• Tegmentum
• Red nucleus (many blood vessels)
• Substantia nigra (pigmented gray matter)
© 2012 Pearson Education, Inc.
Figure 14-8a The Midbrain
Thalamus
Cerebral peduncle
Pineal gland
Red nucleus
Substantia nigra
Corpora quadrigemina
Superior colliculus
Inferior colliculus
Reticular formation
A posterior view. The underlying nuclei are colored only on the right.
© 2012 Pearson Education, Inc.
Figure 14-8b The Midbrain
Cerebral peduncle
Substantia nigra
Red nucleus
Cerebral aqueduct
Superior colliculus
Tectum
Tegmentum
ANTERIOR
POSTERIOR
Cerebellum
A superior view of a transverse section at the level of the midbrain.
© 2012 Pearson Education, Inc.
14-7 The Diencephalon
• The Diencephalon
• Integrates sensory information and motor commands
• Thalamus, epithalamus, and hypothalamus
• The pineal gland
• Found in posterior epithalamus
• Secretes hormone melatonin
© 2012 Pearson Education, Inc.
14-7 The Diencephalon
• The Thalamus
• Filters ascending sensory information for primary
sensory cortex
• Relays information between basal nuclei and cerebral
cortex
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14-7 The Diencephalon
• The Thalamus
• The third ventricle
• Separates left thalamus and right thalamus
• Interthalamic adhesion
• Projection of gray matter
• Extends into ventricle from each side
© 2012 Pearson Education, Inc.
Figure 14-9a The Thalamus
Frontal lobe
A lateral
view of the brain, color coded
to indicate the regions that
receive input from the thalamic
nuclei shown in part (b)
Parietal lobe
Occipital
lobe
© 2012 Pearson Education, Inc.
Figure 14-10a The Hypothalamus in Sagittal Section
A diagrammatic view of the hypothalamus, showing the locations of major nuclei and centers
Suprachiasmatic nucleus
Autonomic centers (parasympathetic)
Paraventricular nucleus
Autonomic centers (sympathetic)
Supraoptic nucleus
Tuberal nuclei
Optic chiasm
Infundibulum
Pituitary gland
Thalamus
Preoptic area
Interthalamic adhesion
Hypothalamus
Mid- brain
Pons
Mamillary body
Tuberal area
© 2012 Pearson Education, Inc.
Figure 14-10b The Hypothalamus in Sagittal Section
Choroid plexus
Pineal gland
Hypothalamus
Aqueduct of midbrain
Cerebellum
Fourth ventricle
Mamillary body
Thalamus (surrounds third ventricle)
Parietal lobe
The hypothalamus and adjacent portions of the brain
© 2012 Pearson Education, Inc.
14-7 The Diencephalon
• Eight Functions of the Hypothalamus
1. Provides subconscious control of skeletal muscle
2. Controls autonomic function
3. Coordinates activities of nervous and endocrine
systems
4. Secretes hormones
• Antidiuretic hormone (ADH) by supraoptic nucleus
• Oxytocin (OT; OXT) by paraventricular nucleus
© 2012 Pearson Education, Inc.
14-7 The Diencephalon
• Eight Functions of the Hypothalamus
5. Produces emotions and behavioral drives
• The feeding center (hunger)
• The thirst center (thirst)
6. Coordinates voluntary and autonomic functions
7. Regulates body temperature
8. Controls circadian rhythms (day–night cycles)
© 2012 Pearson Education, Inc.
14-8 The Limbic System
• The Limbic System
• Is a functional grouping that:
• Establishes emotional states
• Links conscious functions of cerebral cortex with
autonomic functions of brain stem
• Facilitates memory storage and retrieval
© 2012 Pearson Education, Inc.
14-8 The Limbic System
• Components of the Limbic System
• Amygdaloid body
• Acts as interface between the limbic system, the
cerebrum, and various sensory systems
• Limbic lobe of cerebral hemisphere
• Cingulate gyrus
• Dentate gyrus
• Parahippocampal gyrus
• Hippocampus
© 2012 Pearson Education, Inc.
14-8 The Limbic System
• Components of the Limbic System
• Fornix
• Tract of white matter
• Connects hippocampus with hypothalamus
• Anterior nucleus of the thalamus
• Relays information from mamillary body to cingulate
gyrus
• Reticular formation
• Stimulation or inhibition affects emotions (rage, fear,
pain, sexual arousal, pleasure)
© 2012 Pearson Education, Inc.
Figure 14-11a The Limbic System
A diagrammatic sagittal section through the
cerebrum, showing the cortical areas associated
with the limbic system. The parahippocampal
gyrus is shown as though transparent to make
deeper limbic components visible.
Temporal lobe
of cerebrum
Anterior group of
thalamic nuclei
Hypothalamus
Mamillary body
Components of the
Limbic System in
the Diencephalon
Corpus
callosum Fornix
Pineal
gland
Components of the Limbic
System in the Cerebrum
The region of the cerebral
hemisphere shown in green
is known as the limbic lobe.
Cingulate gyrus
(superior portion of
limbic lobe)
Parahippocampal
gyrus (inferior portion
of limbic lobe)
Hippocampus
© 2012 Pearson Education, Inc.
Figure 14-11b The Limbic System
Anterior nucleus of thalamus
Hypothalamic nuclei
Olfactory tract
Amygdaloid body Hippocampus (with dentate gyrus)
Cingulate gyrus
Corpus callosum
Fornix
Mamillary body
Hypothalamus
Parahippocampal gyrus
A three-dimensional reconstruction of the limbic system, showing the relationships among the major components.
© 2012 Pearson Education, Inc.
Table 14-7 The Limbic System
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• The Cerebrum
• Is the largest part of the brain
• Controls all conscious thoughts and intellectual
functions
• Processes somatic sensory and motor information
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Gray Matter
• In cerebral cortex and basal nuclei
• White Matter
• Deep to basal cortex
• Around basal nuclei
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Structures of the Cerebrum
• Gyri of neural cortex
• Increase surface area (number of cortical neurons)
• Longitudinal fissure
• Separates cerebral hemispheres
• Lobes
• Divisions of hemispheres
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Structures of the Cerebrum
• Central sulcus divides:
• Anterior frontal lobe from posterior parietal lobe
• Lateral sulcus divides:
• Frontal lobe from temporal lobe
• Parieto-occipital sulcus divides:
• Parietal lobe from occipital lobe
© 2012 Pearson Education, Inc.
Figure 14-12a The Brain in Lateral View
Lateral sulcus
Pons
Medulla oblongata
FRONTAL
LOBE
Central sulcus
TEMPORAL LOBE
Lateral view, cadaver brain
Cerebellum
OCCIPITAL
LOBE
PARIETAL LOBE
© 2012 Pearson Education, Inc.
Figure 14-12b The Brain in Lateral View
FRONTAL
LOBE
Precentral
gyrus
Central
sulcus
Postcentral
gyrus
Lateral sulcus
Pons
PARIETAL LOBE
OCCIPITAL
LOBE
TEMPORAL
LOBE
Cerebellum
Medulla oblongata
Lateral view
© 2012 Pearson Education, Inc.
Figure 14-12d The Brain in Lateral View
Central sulcus Postcentral gyrus
PARIETAL LOBE
OCCIPITAL
LOBE
Parieto-
occipital sulcus
Cerebellum Pons
Medulla oblongata
Midsagittal section
TEMPORAL LOBE
FRONTAL
LOBE
Precentral gyrus
Cingulate
gyrus
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Three Functional Principles of the Cerebrum
1. Each cerebral hemisphere receives sensory
information from, and sends motor commands to,
the opposite side of the body
2. The two hemispheres have different functions,
although their structures are alike
3. Correspondence between a specific function and a
specific region of cerebral cortex is not precise
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• The Basal Nuclei
• Are masses of gray matter
• Are embedded in white matter of cerebrum
• Direct subconscious activities
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Anatomy of Basal Nuclei
• Caudate nucleus
• Curving, slender tail
• Lentiform nucleus
• Globus pallidus
• Putamen
© 2012 Pearson Education, Inc.
Figure 14-14a The Basal Nuclei
Lentiform
nucleus
Tail of caudate
nucleus
Thalamus
Head of
caudate
nucleus
Amygdaloid
body
The relative
positions of the
basal nuclei in the
intact brain, lateral view
© 2012 Pearson Education, Inc.
Figure 14-14b The Basal Nuclei
Head of caudate nucleus
Internal capsule
Putamen
Thalamus
Choroid plexus
Pineal gland
Lateral ventricle
(posterior horn)
Fornix
Third ventricle
Fornix (cut edge)
Septum pellucidum
Corpus callosum
Lateral ventricle
(anterior horn)
A horizontal section as seen in a dissection
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Figure 14-14c The Basal Nuclei
Head of caudate
nucleus
Lateral
ventricle
Corpus callosum
Septum pellucidum
Internal capsule
Lateral sulcus
Anterior
commissure
Tip of lateral
ventricle
Frontal section
Insula
Claustrum
Putamen
Globus
pallidus
Lentiform
nucleus
Amygdaloid body
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Functions of Basal Nuclei
• Involved with:
• The subconscious control of skeletal muscle tone
• The coordination of learned movement patterns
(walking, lifting)
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Motor and Sensory Areas of the Cortex
• Central sulcus separates motor and sensory areas
• Motor areas
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Motor and Sensory Areas of the Cortex
• Sensory areas
• Primary sensory cortex
• Surface of postcentral gyrus
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Special Sensory Cortexes
• Visual cortex
• Information from sight receptors
• Auditory cortex
• Information from sound receptors
• Olfactory cortex
• Information from odor receptors
• Gustatory cortex
• Information from taste receptors
© 2012 Pearson Education, Inc.
Figure 14-15a Motor and Sensory Regions of the Cerebral Cortex
Major anatomical landmarks on the surface of
the left cerebral hemisphere. The lateral sulcus
has been pulled apart to expose the insula.
FRONTAL LOBE
Prefrontal cortex
Gustatory cortex
Insula
Lateral sulcus
Olfactory cortex
Somatic motor association area (premotor cortex)
Primary motor cortex (precentral gyrus)
Central sulcus Primary sensory cortex (postcentral gyrus)
PARIETAL LOBE
TEMPORAL LOBE
OCCIPITAL LOBE
Somatic sensory association area
Visual association area
Visual cortex
Auditory cortex
Auditory association area
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Association Areas
• Sensory association areas
• Monitor and interpret arriving information at sensory
areas of cortex
• Somatic sensory association area
• Interprets input to primary sensory cortex (e.g.,
recognizes and responds to touch)
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Sensory Association Areas
• Visual association area
• Interprets activity in visual cortex
• Auditory association area
• Monitors auditory cortex
• Somatic motor association area (premotor cortex)
• Coordinates motor responses (learned movements)
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Integrative Centers
• Are located in lobes and cortical areas of both
cerebral hemispheres
• Receive information from association areas
• Direct complex motor or analytical activities
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• General Interpretive Area
• Also called Wernicke’s area
• Present in only one hemisphere
• Receives information from all sensory association
areas
• Coordinates access to complex visual and auditory
memories
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Other Integrative Areas
• Speech center
• Is associated with general interpretive area
• Coordinates all vocalization functions
• Prefrontal cortex of frontal lobe
• Integrates information from sensory association areas
• Performs abstract intellectual activities (e.g., predicting
consequences of actions)
© 2012 Pearson Education, Inc.
Figure 14-15b Motor and Sensory Regions of the Cerebral Cortex
General interpretive area
Frontal eye field
Speech center
Prefrontal cortex
The left hemisphere generally contains the
general interpretive area and the speech center.
The prefrontal cortex of each hemisphere is
involved with conscious intellectual functions.
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• Hemispheric Lateralization
• Functional differences between left and right
hemispheres
• Each cerebral hemisphere performs certain functions
that are not ordinarily performed by the opposite
hemisphere
© 2012 Pearson Education, Inc.
14-9 The Cerebrum
• The Left Hemisphere
• In most people, left brain (dominant hemisphere) controls:
• Reading, writing, and math
• Decision making
• Speech and language
• The Right Hemisphere
• Right cerebral hemisphere relates to:
• Senses (touch, smell, sight, taste, feel)
• Recognition (faces, voice inflections)
© 2012 Pearson Education, Inc.
Figure 14-16 Hemispheric Lateralization
Left Cerebral Hemisphere
LEFT HAND
Prefrontal
cortex
Speech center
Writing
Auditory cortex
General interpretive center
(language and mathematical
calculation)
Visual cortex
(right visual field)
C O R P U S
C A L L O S U M
© 2012 Pearson Education, Inc.
Figure 14-16 Hemispheric Lateralization
Right Cerebral Hemisphere
RIGHT HAND
Prefrontal
cortex
Anterior commissure
Analysis by touch
Auditory cortex
Spatial visualization
and analysis
Visual cortex
(left visual field)
C O R P U S
C A L L O S U M
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Cranial Nerves
• 12 pairs connected to brain
• Four Classifications of Cranial Nerves
1. Sensory nerves carry somatic sensory information, including
touch, pressure, vibration, temperature, and pain
2. Special sensory nerves carry sensations such as smell, sight,
hearing, balance
3. Motor nerves: axons of somatic motor neurons
4. Mixed nerves: mixture of motor and sensory fibers
© 2012 Pearson Education, Inc.
Figure 14-18 Origins of the Cranial Nerves
Olfactory bulb: termination
of olfactory nerve (I)
Olfactory tract
Optic nerve (II)
Infundibulum
Oculomotor nerve (III)
Pons
Basilar artery
Vertebral artery
Cerebellum
Medulla oblongata
Spinal cord
© 2012 Pearson Education, Inc.
Figure 14-18 Origins of the Cranial Nerves
Optic chiasm
Optic tract
Mamillary body
Trochlear nerve (IV)
Trigeminal nerve (V)
Abducens nerve (VI)
Vestibulocochlear
nerve (VIII)
Facial nerve (VII)
Glossopharyngeal
nerve (IX)
Vagus nerve (X)
Hypoglossal nerve (XII)
Accessory nerve (XI)
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Olfactory Nerves (I)
• Primary function:
• Special sensory (smell)
• Origin:
• Receptors of olfactory epithelium
• Pathway:
• Olfactory foramina in cribriform plate of ethmoid
• Destination:
• Olfactory bulbs
© 2012 Pearson Education, Inc.
Figure 14-19 The Olfactory Nerve
Olfactory tract
(to olfactory cortex
of cerebrum)
Left olfactory
bulb (termination
of olfactory nerve)
OLFACTORY
NERVE (N I)
Olfactory
nerve fibers
Cribriform plate
of ethmoid
Olfactory
epithelium
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Optic Nerves (II)
• Primary function:
• Special sensory (vision)
• Origin:
• Retina of eye
• Pathway:
• Optic canals of sphenoid
• Destination:
• Diencephalon via optic chiasm
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Optic Nerve Structures
• Optic chiasm
• Where sensory fibers converge
• And cross to opposite side of brain
• Optic tracts
• Reorganized axons
• Leading to lateral geniculate nuclei
© 2012 Pearson Education, Inc.
Figure 14-20 The Optic Nerve
Pituitary
gland
Midbrain
(cut)
Visual cortex
(in occipital lobes)
Optic projection
fibers
Optic tract
Optic chiasm
OPTIC NERVE
(N II)
Olfactory bulb
Olfactory tract
Eye
Lateral geniculate nucleus (in thalamus)
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Oculomotor Nerves (III)
• Primary function:
• Motor (eye movements)
• Origin:
• Midbrain
• Pathway:
• Superior orbital fissures of sphenoid
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Trochlear Nerves (IV)
• Primary function:
• Motor (eye movements)
• Origin:
• Midbrain
• Pathway:
• Superior orbital fissure of sphenoid
• Destination:
• Superior oblique muscle
© 2012 Pearson Education, Inc.
Figure 14-21 Cranial Nerves Controlling the Extra-Ocular Muscles
Superior
oblique
muscle
Trochlea
Superior
rectus
muscle
Levator
palpebrae
superioris
muscle
Inferior
rectus
muscle
Ciliary
ganglion
Lateral rectus
muscle (cut)
ABDUCENS
NERVE (N VI)
OPTIC
NERVE (N II) Optic
chiasm
OCULOMOTOR
NERVE (N III)
TROCHLEAR
NERVE (N IV)
Trigeminal
nerve (N V), cut
Vestibulocochlear
nerve (N VIII), cut
Facial nerve
(N VII), cut Medial
rectus
muscle
Inferior
oblique
muscle
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Trigeminal Nerves (V)
• Primary function:
• Mixed (sensory and motor) to face
• Origin:
• Ophthalmic branch (sensory)
• Orbital structures
• Nasal cavity
• Skin of forehead, upper eyelid, and eyebrow
• Part of nose
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Trigeminal Nerves (V)
• Origin:
• Maxillary branch (sensory)
• Lower eyelid
• Upper lip, gums, and teeth
• Cheek and nose
• Palate and part of pharynx
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Trigeminal Nerves (V)
• Origin:
• Mandibular branch (sensory)
• Lower gums, teeth, and lips
• Palate and part of tongue
• Mandibular branch (motor)
• Motor nuclei of pons
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Trigeminal Nerves (V)
• Pathway:
• Ophthalmic branch
• Superior orbital fissure
• Maxillary branch
• Foramen rotundum
• Mandibular branch
• Foramen ovale
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Trigeminal Nerves (V)
• Destination:
• Sensory nerves
• Sensory nuclei in pons
• Motor nerves of mandibular branch
• Muscles of mastication
© 2012 Pearson Education, Inc.
Figure 14-22 The Trigeminal Nerve
Supra-orbital
nerves
Ciliary ganglion
Foramen
rotundum
Infra-orbital
nerve
Lingual nerve
Submandibular
ganglion
Mental nerve
Pterygopalatine
ganglion
Mandibular
branch
Otic ganglion
Foramen ovale
Maxillary
branch
Pons
TRIGEMINAL
NERVE (N V)
Semilunar
ganglion
Ophthalmic
branch
Superior orbital fissure
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Facial Nerves (VII)
• Primary function:
• Mixed (sensory and motor) to face
• Origin:
• Sensory
• Taste receptors on anterior 2/3 of tongue
• Motor
• Motor nuclei of pons
• Pathway:
• Internal acoustic meatus to facial canals (stylomastoid foramina)
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Facial Nerves (VII)
• Destination:
• Sensory
• Sensory nuclei of pons
• Somatic motor
• Muscles of facial expression
• Visceral motor
• Tear and nasal mucous glands
• Submandibular and sublingual salivary glands
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Facial Nerve Structures
• Facial nerve branches
• Temporal
• Zygomatic
• Buccal
• Mandibular
• Cervical branches
© 2012 Pearson Education, Inc.
Figure 14-23a The Facial Nerve
Pterygopalatine
ganglion
Greater petrosal
nerve
Geniculate
ganglion
Pons
FACIAL
NERVE (N VII)
Posterior
auricular
branch
Stylomastoid
foramen
Chorda tympani nerve
(with mandibular
branch of N V)
Lingual branch
(with lingual nerve
of N V)
Submandibular
ganglion
Temporal
branch
Zygomatic
branches
Buccal
branch
Mandibular
branch
Cervical
branch
The origin and branches of the facial nerve
© 2012 Pearson Education, Inc.
Figure 14-23b The Facial Nerve
Temporal
branch
Zygomatic
branch
Buccal branch
Mandibular
branch
Cervical branch
The superficial distribution
of the five major branches
of the facial nerve
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Vestibulocochlear Nerves (VIII)
• Primary function:
• Special sensory
• Vestibular branch
• Balance and equilibrium
• Cochlear branch
• Hearing
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Vestibulocochlear Nerves (VIII)
• Origin:
• Receptors of inner ear
• Pathway:
• Internal acoustic meatus of temporal bones
• Destination:
• Vestibular and cochlear nuclei of pons and medulla
oblongata
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Vestibulocochlear Nerve Structures
• Vestibular branch
• Originates at receptors of vestibule (balance)
• Connects to vestibular nuclei of pons and medulla
oblongata
• Cochlear branch
• Originates at sensors of cochlea (hearing)
• Connects with cochlear nuclei of pons and medulla
oblongata
© 2012 Pearson Education, Inc.
Figure 14-24 The Vestibulocochlear Nerve
Tympanic cavity
(middle ear)
Semicircular
canals
Vestibular
branch (N VIII)
Facial nerve
(N VII),
cut
Internal
acoustic
meatus
VESTIBULOCOCHLEAR
NERVE (N VIII)
N V
Pons
N VI
N VII
N XII
N IX
N X
N XI
Medulla
oblongata
Cochlear branch (N VIII) Cochlea Auditory tube Tympanic membrane
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Glossopharyngeal Nerves (IX)
• Primary function:
• Mixed (sensory and motor) to head and neck
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Glossopharyngeal Nerves (IX)
• Origins:
• Sensory
• Posterior 1/3 of tongue
• Part of pharynx and palate
• Carotid arteries
• Motor
• Motor nuclei of medulla oblongata
© 2012 Pearson Education, Inc.
Figure 14-25 The Glossopharyngeal Nerve
Otic ganglion
Inferior
(petrosal)
ganglion
Lingual
branch
Carotid body
Carotid sinus
Common carotid artery
Carotid sinus branch
Pharyngeal branches
Parotid salivary gland
Superior (jugular)
ganglion
Medulla oblongata
GLOSSOPHARYNGEAL
NERVE (N IX)
Pons
N VII
N VI
N V
N VIII
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Vagus Nerves (X)
• Primary function:
• Mixed (sensory and motor)
• Widely distributed in thorax and abdomen
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Vagus Nerves (X)
• Origins:
• Sensory
• Part of pharynx
• Auricle and external acoustic meatus
• Diaphragm
• Visceral organs of thoracic and abdominopelvic cavities
• Motor
• Motor nuclei in medulla oblongata
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Vagus Nerves (X)
• Pathway:
• Jugular foramina
• Between occipital and temporal bones
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Vagus Nerves (X)
• Destination:
• Sensory
• Sensory nuclei and autonomic centers of
medulla oblongata
• Visceral motor
• Muscles of the palate and pharynx
• Muscles of the digestive, respiratory, and
cardiovascular systems in thoracic and
abdominal cavities
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• Vagus Nerve Structures
• Vagus nerves
• Branch and radiate extensively
• Superior (jugular) ganglion and inferior (nodose)
ganglion
• Hold sensory neurons
© 2012 Pearson Education, Inc.
Figure 14-26 The Vagus Nerve
Superior
pharyngeal
branch
VAGUS
NERVE (N X)
Pons
Superior
laryngeal nerve
Internal branch
External branch
Inferior
ganglion
of vagus
nerve
Medulla oblongata
Auricular branch
to external ear
Superior ganglion
of vagus nerve
Pharyngeal branch
Superior laryngeal nerve
© 2012 Pearson Education, Inc.
Figure 14-26 The Vagus Nerve
Recurrent
laryngeal nerve
Cardiac branches
Cardiac plexus
Right lung Left lung
Anterior vagal trunk
Spleen
Celiac plexus
Stomach
Liver
Colon
Pancreas
Small intestine
Hypogastric plexus
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Accessory Nerves (XI)
• Primary function:
• Motor to muscles of neck and upper back
• Origin:
• Motor nuclei of spinal cord and medulla oblongata
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Accessory Nerves (XI)
• Pathway:
• Jugular foramina between occipital and temporal bones
• Destination:
• Internal branch
• Voluntary muscles of palate, pharynx, and larynx
• External branch
• Sternocleidomastoid and trapezius muscles
© 2012 Pearson Education, Inc.
14-10 Cranial Nerves
• The Hypoglossal Nerves (XII)
• Primary function:
• Motor (tongue movements)
• Origin:
• Motor nuclei of medulla oblongata
• Pathway:
• Hypoglossal canals of occipital bone
• Destination:
• Muscles of tongue
© 2012 Pearson Education, Inc.
Figure 14-27 The Accessory and Hypoglossal Nerves
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal,
pharyngeal, and laryngeal
muscles with vagus nerve
Intrinsic muscles of tongue
Styloglossus muscle
Genioglossus muscle
Geniohyoid muscle
Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Sternohyoid muscle
Sternothyroid muscle
Trigeminal nerve (N V)
Medulla oblongata
Cranial root of N XI
Spinal
root of N XI
External
branch of N XI
Spinal cord
Omohyoid muscle
Sternocleidomastoid
muscle
Ansa cervicalis
(cervical plexus)
Trapezius muscle
© 2012 Pearson Education, Inc.
14-10 Cranial Reflexes
• Cranial Reflexes
• Monosynaptic and polysynaptic reflex arcs
• Involve sensory and motor fibers of cranial nerves
• Clinically useful to check cranial nerve for brain
damage
© 2012 Pearson Education, Inc.
Table 14-10 Cranial Reflexes
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