© 2015 Pearson Education, Inc.

Introduction The brain is a complex three-dimensional structure that performs a bewildering array of functions Think of the brain as an organic computer However, the brain is far more versatile than a computer The brain is far more complex than the spinal cord The brain consists of roughly 20 billion neurons © 2015 Pearson Education, Inc. 2

An Introduction to the Organization of the Brain
Embryology of the Brain The CNS begins as a neural tube The lumen of the tube (neurocoel) is filled with fluid The lumen of the tube will expand thus forming the various ventricles of the brain In the fourth week of development, the cephalic area of the neural tube enlarges to form: Prosencephalon Mesencephalon Rhombencephalon © 2015 Pearson Education, Inc. 3

Table 16.1 Development of the Human Brain
© 2015 Pearson Education, Inc.

Embryology of the Brain (continued) Prosencephalon eventually develops to form: Telencephalon forms: Cerebrum Diencephalon forms: Epithalamus, thalamus, and hypothalamus. © 2015 Pearson Education, Inc. 5

Embryology of the Brain (continued) Rhombencephalon Eventually develops to form: Metencephalon: forms the pons and cerebellum Myelencephalon: forms the medulla oblongata © 2015 Pearson Education, Inc. 9

Figure 16.1 Major Divisions of the Brain
Left cerebral hemisphere Gyri CEREBRUM Sulci • Conscious thought processes, intellectual functions • Memory storage and processing • Conscious and subconscious regulation of skeletal muscle contractions Fissures DIENCEPHALON THALAMUS • Relay and processing centers for sensory information HYPOTHALAMUS • Centers controlling emotions, autonomic functions, and hormone production CEREBELLUM • Coordinates complex somatic motor patterns • Adjusts output of other somatic motor centers in brain and spinal cord Spinal cord MESENCEPHALON Brain stem • Processing of visual and auditory data • Generation of reflexive somatic motor responses • Maintenance of consciousness PONS • Relays sensory information to cerebellum and thalamus • Subconscious somatic and visceral motor centers MEDULLA OBLONGATA • Relays sensory information to thalamus and to other portions of the brain stem • Autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities) © 2015 Pearson Education, Inc.

Figure 16.13a Sectional Views of the Brain
Precentral gyrus Central sulcus Postcentral gyrus Cingulate gyrus Fornix Corpus callosum Thalamus Membranous portion of epithalamus Septum pellucidum Hypothalamus Interventricular foramen Parieto-occipital sulcus Pineal gland Frontal lobe Corpora Quadrigemina Anterior commissure Superior colliculus Optic chiasm Inferior colliculus Mamillary body Aqueduct of midbrain Temporal lobe Cerebellum Mesencephalon Fourth ventricle Pons Medulla oblongata a A sagittal section through the brain © 2015 Pearson Education, Inc.

Major Regions and Landmarks Medulla oblongata Relays information to the thalamus and brain stem Regulates heart rate, blood pressure, and digestion Pons Relays information to the cerebellum and the thalamus Regulates somatic and visceral motor centers © 2015 Pearson Education, Inc. 14

Major Regions and Landmarks Mesencephalon (midbrain) Processes visual and auditory data Maintains consciousness and alertness Involved with reflexive somatic motor responses to stimuli © 2015 Pearson Education, Inc. 16

Major Regions and Landmarks Diencephalon Epithalamus Contains the pineal gland Thalamus Relays information to the cerebrum Processes sensory information Hypothalamus Involved in emotions, thirst, some habitual activity © 2015 Pearson Education, Inc. 18

Major Regions and Landmarks Cerebellum Coordinates somatic motor function Adjusts output of somatic motor centers resulting in smooth operation Cerebrum (telencephalon) Conscious thought processes Intellectual functions Memory storage Conscious regulation of skeletal muscle contractions © 2015 Pearson Education, Inc. 20

Gray Matter and White Matter Organization The cerebrum consists of: Inner region of gray matter Surrounded by tracts of white matter Gray matter consists of cell bodies © 2015 Pearson Education, Inc. 22

Figure 16.2d Ventricles of the Brain
Ventricular System of the Brain Lateral ventricles in cerebral hemispheres Septum pellucidum Interventricular foramen Third ventricle Aqueduct of midbrain Inferior horn of lateral ventricles Fourth ventricle Cerebellum Central canal d Diagrammatic coronal section showing the interconnections between the ventricles © 2015 Pearson Education, Inc.

The Ventricular System of the Brain Ventricles are fluid-filled cavities Filled with cerebrospinal fluid (CSF) Fluid transports nutrients to the CNS and transports waste away from the CNS CSF also provides cushion for the CNS © 2015 Pearson Education, Inc. 24

The Ventricular System of the Brain There are four ventricles Ventricles 1 and 2 (called lateral ventricles) Located in the cerebral hemispheres (separated by a partition called the septum pellucidum) Ventricle 3 is in the diencephalon Ventricle 4 lies between the pons and the cerebellum © 2015 Pearson Education, Inc. 25

Figure 16.2a Ventricles of the Brain
Anterior horns of lateral ventricles Cerebral hemispheres Lateral ventricles Interventricular foramen Third ventricle Posterior horns of lateral ventricles Inferior horns of lateral ventricles Aqueduct of midbrain Pons Fourth ventricle Medulla oblongata Central canal Cerebellum Spinal cord a Orientation and extent of the ventricles as seen in a lateral view of a transparent brain © 2015 Pearson Education, Inc.

The Ventricular System of the Brain Lateral ventricles (ventricles 1 and 2) Main portion of the ventricle lies in the parietal lobes Each has an anterior horn extending into the frontal lobe Each has a posterior horn extending into the occipital lobe Each has an inferior horn extending into the temporal lobe Each communicates with the third ventricle Through the interventricular foramen © 2015 Pearson Education, Inc. 27

The Ventricular System of the Brain Third ventricle Communicates with the fourth ventricle Through the aqueduct of the midbrain Fourth ventricle Communicates with the central canal of the spinal cord © 2015 Pearson Education, Inc. 28

Figure 16.2a Ventricles of the Brain
Anterior horns of lateral ventricles Cerebral hemispheres Lateral ventricles Interventricular foramen Third ventricle Posterior horns of lateral ventricles Inferior horns of lateral ventricles Aqueduct of midbrain Pons Fourth ventricle Medulla oblongata Central canal Cerebellum Spinal cord a Orientation and extent of the ventricles as seen in a lateral view of a transparent brain © 2015 Pearson Education, Inc.

Figure 16.2c Ventricles of the Brain
Longitudinal fissure Ventricular System of the Brain Lateral ventricles in cerebral hemispheres Interventricular foramen Third ventricle Inferior horn of lateral ventricle Aqueduct of midbrain Pons Fourth ventricle Cerebellum Medulla oblongata Central canal c Anterior view of the ventricles as if seen through a transparent brain © 2015 Pearson Education, Inc.

Protection and Support of the Brain
Protection involves: Bones of the skull Parietal, frontal, occipital, and temporal bones Cranial meninges Dura mater, arachnoid mater, and pia mater Cerebrospinal fluid Blood–brain barrier © 2015 Pearson Education, Inc. 31

The Cranial Meninges The cranial meninges surround the brain and the spinal cord There are three layers of the meninges Dura mater Most superficial layer (outermost layer) Arachnoid mater Middle layer Pia mater Deepest (innermost layer) © 2015 Pearson Education, Inc. 32

Figure 16.3a Relationships among the Brain, Cranium, and Meninges
Dura mater (endosteal layer) Cranium Dural sinus Dura mater (meningeal layer) Cerebral cortex Subdural space Arachnoid mater Cerebral cortex Pia mater Subarachnoid space Cerebellum Medulla oblongata Spinal cord a Lateral view of the brain showing its position in the cranium and the organization of the meningeal coverings. © 2015 Pearson Education, Inc.

Figure 16.4 The Cranial Meninges, Part I
ANTERIOR Cranium Loose connective tissue and periosteum of cranium Dura mater Subarachnoid space Epicranial aponeurosis Arachnoid mater Scalp Cerebral cortex covered by pia mater POSTERIOR © 2015 Pearson Education, Inc.

The Cranial Meninges The Dura Mater Consists of two layers Endosteal layer Outermost layer of the dura mater This is the layer felt within the anterior fontanel of a baby Fused to the periosteum lining of the cranial bones Meningeal layer Innermost layer of the dura mater Space between the two layers contains the dural sinus © 2015 Pearson Education, Inc. 35

Folds of the Dura Mater Falx cerebri Meningeal layer that extends into the longitudinal fissure Inferior/anterior portion attaches to the crista galli Inferior/posterior portion attaches to the internal occipital crest and the tentorium cerebelli Tentorium cerebelli Separates the cerebellar hemispheres from the cerebral hemispheres Extends across the cranium at right angles to the falx cerebri © 2015 Pearson Education, Inc. 38

Folds of the Dura Mater (continued) Falx cerebelli Extends from the tentorium cerebelli to separate the cerebellar hemispheres Diaphragma sellae Lines the sella turcica of the sphenoid bone It anchors the dura mater to the sphenoid bone It encases the pituitary gland © 2015 Pearson Education, Inc. 39

Figure 16.5a The Cranial Meninges, Part II
Superior sagittal sinus Cranial Meninges Dura mater Subdural space Arachnoid mater Arachnoid trabeculae Arachnoid granulation Pia mater Falx cerebri Cerebral vein Subarachnoid space Cerebral cortex a Organization and relationship of the cranial meninges to the brain. © 2015 Pearson Education, Inc.

Figure 16.3b Relationships among the Brain, Cranium, and Meninges
Superior sagittal sinus Inferior sagittal sinus Cranium Diaphragma sellae Dura Mater Falx cerebri Tentorium cerebelli Pituitary gland Diaphragma sellae Sella turcica of sphenoid Falx cerebelli Transverse sinus b A corresponding view of the cranial cavity with the brain removed showing the orientation and extent of the falx cerebri and tentorium cerebelli. © 2015 Pearson Education, Inc.

The Cranial Meninges The Arachnoid Mater Consists of projections called arachnoid granulations CSF flows through these to enter into venous circulation Consists of weblike material underlining the arachnoid layer These collagenous fibers help anchor cerebral blood vessels © 2015 Pearson Education, Inc. 42

The Cranial Meninges The Pia Mater Attached to the surface of the brain Follows the sulci and gyri of the brain Helps to anchor the larger blood vessels of the cerebrum © 2015 Pearson Education, Inc. 44

Figure 16.5a The Cranial Meninges, Part II
Superior sagittal sinus Cranial Meninges Dura mater Subdural space Arachnoid mater Arachnoid trabeculae Arachnoid granulation Pia mater Falx cerebri Cerebral vein Subarachnoid space Cerebral cortex a Organization and relationship of the cranial meninges to the brain. © 2015 Pearson Education, Inc.

Figure 16.5b The Cranial Meninges, Part II
Subdural space Subarachnoid space Cranial Meninges Dura mater Arachnoid mater Arachnoid trabeculae Pia mater Cerebral vein Cerebral cortex Perivascular space b A detailed view of the arachnoid mater, the subarachnoid space, and the pia mater. Note the relationship between the cerebral vein and the subarachnoid space. © 2015 Pearson Education, Inc.

Blood–Brain Barrier The lining of the blood vessels consists of endothelial cells that are highly interconnected by tight junctions Due to this tight connection, only lipid-soluble material can pass from the blood to the cells of the brain and spinal cord Water-soluble material can only pass via the action of transport mechanisms These transport mechanisms are very specific © 2015 Pearson Education, Inc. 47

Blood–Brain Barrier The blood-brain barrier is intact throughout the CNS except in three areas Portions of the hypothalamus Pineal gland The roof portions of the third and fourth ventricles © 2015 Pearson Education, Inc. 48

Cerebrospinal Fluid (CSF) Prevents contact of neural tissue with the surrounding bones Provides support Transports nutrients to the CNS tissue Transports waste away from the CNS © 2015 Pearson Education, Inc. 49

Formation of CSF Produced by the ependymal cells of the choroid plexus They actively transport nutrients, vitamins, and ions into the CSF They actively remove waste from the CSF © 2015 Pearson Education, Inc. 50

Figure 16.6 The Choroid Plexus and Blood–Brain Barrier
INTERSTITIAL FLUID IN THALAMUS Nutrients (especially glucose) Oxygen Ependymal cells Capillary Capillary Endothelial cell CO2 Waste products Blood–brain barrier Tight junction Astrocyte Neuron a The location of the choroid plexus in each of the four ventricles of the brain. Choroid plexus cells Waste products Ions Amino acids (when necessary) Ions (Na+, K+, Cl–, HCO3–, Ca2+, Mg2+) Vitamins Organic nutrients Oxygen b The structure and function of the choroid plexus. The ependymal cells are a selective barrier, actively transporting nutrients, vitamins, and ions into the CSF. When necessary, these cells also actively remove ions or compounds from the CSF to stabilize its composition. Tight junction CHOROID PLEXUS CEREBROSPINAL FLUID IN THIRD VENTRICLE © 2015 Pearson Education, Inc.

Circulation of CSF CSF from the choroid plexus of the lateral ventricles Flows through the interventricular foramen Flows into the third ventricle Flows into the aqueduct of the midbrain Flows into the fourth ventricle Through the lateral aperture and median aperture Most flows into the subarachnoid space and a small amount enters the central canal of the spinal cord Flows around the brain and spinal cord eventually enters circulation via the arachnoid granulations © 2015 Pearson Education, Inc. 52

Figure 16.7 Circulation of Cerebrospinal Fluid
Extension of choroid plexus into lateral ventricle Arachnoid granulations Superior sagittal sinus Dura mater (endosteal layer) Cranium Arachnoid granulation Fluid movement Arachnoid trabecula Cerebral cortex Dura mater (meningeal layer) Superior sagittal sinus Pia mater Subdural space Subarachnoid space Choroid plexus of third ventricle Arachnoid mater Aqueduct of midbrain Lateral aperture Choroid plexus of fourth ventricle Median aperture Central canal Arachnoid mater Subarachnoid space Dura mater Spinal cord Filum terminale © 2015 Pearson Education, Inc.

The Medulla Oblongata The medulla oblongata is continuous with the spinal cord to the brain stem All communication between the brain and spinal cord passes through the medulla oblongata Nuclei in the medulla oblongata are: Relay stations for sensory or motor pathways Associated with cranial nerves connected to the medulla oblongata Associated with the autonomic control of visceral organs © 2015 Pearson Education, Inc. 54

The Medulla Oblongata Relay Stations
Nucleus gracilis and nucleus cuneatus Pass somatic sensory information to the thalamus Olivary nuclei Pass information from the cerebrum, spinal cord, diencephalon, and brain stem to the cerebellum © 2015 Pearson Education, Inc. 55

Figure 16.8a The Medulla Oblongata
Olivary nucleus Cardiovascular centers Medulla oblongata Pons Solitary nucleus Nucleus cuneatus Olive Nucleus gracilis Pyramids Reticular formation Lateral white column Spinal cord a Anterior view © 2015 Pearson Education, Inc.

The Medulla Oblongata Nuclei of Cranial Nerves Autonomic Nuclei
Contains sensory and motor nuclei of cranial nerves: VIII, IX, X, XI, and XII Autonomic Nuclei Major reflex centers include: Cardiovascular centers (cardiac and vasomotor) Respiratory centers (rhythmic breathing) © 2015 Pearson Education, Inc. 57

Figure 16.8b The Medulla Oblongata
Olivary nuclei Attachment to membranous roof of fourth ventricle Cardiovascular centers Respiratory rhythmicity centers Nucleus gracilis Nucleus cuneatus Other nuclei/centers Lateral white column Reticular formation Posterior white columns Posterior median sulcus Spinal cord b Posterolateral view © 2015 Pearson Education, Inc.

The Pons The pons is a prominent bulge superior to the medulla oblongata and consists of: Sensory and motor nuclei for cranial nerves: V, VI, VII, and VIII Nuclei involved with involuntary control of breathing: Consist of apneustic center and pneumotaxic center Nuclei that relay cerebellar commands: Consist of cerebellar peduncles Ascending, descending, and transverse tracts © 2015 Pearson Education, Inc. 59

Figure 16.12a The Hypothalamus
Parietal lobe Corpus callosum Choroid plexus in epithalamus Septum pellucidum Thalamus (surrounds third ventricle) Fornix Anterior cerebral artery Pineal gland Frontal lobe Hypothalamus Aqueduct of midbrain Anterior commissure Cerebellum Optic chiasm Fourth ventricle Optic nerve Infundibulum (cut) Tuberal area Mamillary body a Midsagittal section through the brain. This view shows the major features of the diencephalon and adjacent portions of the brain stem. © 2015 Pearson Education, Inc.

Descending tracts Ascending tracts Transverse fibers Pons Cerebellum
Figure 16.9 The Pons Descending tracts Ascending tracts Transverse fibers Pons Cerebellum Fourth ventricle Pneumotaxic center Apneustic center Medulla oblongata Reticular formation Olivary nucleus © 2015 Pearson Education, Inc.

The Mesencephalon Mesencephalon (also called the midbrain)
Consists of two pairs of nuclei collectively called corpora quadrigemina Responsible for processing auditory and visual stimuli Auditory processing occurs in the inferior colliculus Visual processing occurs in the superior colliculus Consists of nuclei of the reticular formation Involved in maintaining alertness © 2015 Pearson Education, Inc. 62

The Mesencephalon Mesencephalon (continued) Consists of: Red nucleus
Integrates information between the cerebrum and cerebellum Substantia nigra Regulates motor output of the basal nuclei Cerebral peduncles Have ascending fibers that synapse in the thalamus and descending fibers of the corticospinal pathway © 2015 Pearson Education, Inc. 64

Figure 16.10b The Mesencephalon
Pineal gland Thalamus Superior colliculi Inferior colliculi Substantia nigra Red nuclei Reticular formation Cerebral peduncles b Diagrammatic view of the diencephalon and brain stem. This view is drawn as if transparent, to show the positions of important nuclei. © 2015 Pearson Education, Inc.

The Diencephalon The diencephalon consists of: Epithalamus Thalamus
Hypothalamus © 2015 Pearson Education, Inc. 66

The Diencephalon The Epithalamus Forms the roof of the third ventricle
Posterior portion contains the pineal gland Produces the hormone melatonin Regulates our day-night cycles © 2015 Pearson Education, Inc. 68

The Diencephalon The Thalamus Forms the walls of the third ventricle
There is a right and a left thalamus Thalamic nuclei are egg-shaped Each thalamic nucleus is divided into: Anterior nuclei: part of the limbic system Medial nuclei: relay information to the frontal lobe Ventral nuclei: relay information to the parietal lobes Posterior nuclei: relay information to the occipital lobe Lateral nuclei: adjust activity in the cingulate gyrus © 2015 Pearson Education, Inc. 69

Lateral view of the brain showing the positions of the major thalamic
Figure 16.11a The Thalamus Frontal lobe Parietal lobe Occipital lobe a Lateral view of the brain showing the positions of the major thalamic structures. Functional areas of cerebral cortex are also indicated, with colors corresponding to those of the associated thalamic nuclei. © 2015 Pearson Education, Inc.

Enlarged view of the thalamic nuclei of the left side. The color
Figure 16.11b The Thalamus Limbic system Frontal lobes Parietal lobe and cingulate gyrus Association areas of cerebral cortex Medial group Anterior group Lateral group Posterior group Pulvinar Ventral group Auditory input Medial geniculate nucleus Basal nuclei General sensory input Lateral geniculate nucleus Visual input Cerebellum b Enlarged view of the thalamic nuclei of the left side. The color of each nucleus or group of nuclei matches the color of the associated cortical region. The boxes either provide examples of the types of sensory input relayed to the basal nuclei and cerebral cortex or indicate the existence of important feedback loops involved with emotional states, learning, and memory. © 2015 Pearson Education, Inc.

The Diencephalon The Hypothalamus
Forms the floor of the third ventricle Consists of numerous nuclei Consists of an infundibulum, which connects to the pituitary gland Consists of the mamillary body on the posterior wall of the hypothalamus © 2015 Pearson Education, Inc. 72

The Diencephalon The Hypothalamus (continued)
Consists of nuclei to control: Subconscious control of skeletal muscles Heart rate, blood pressure, respiration, and digestive functions Secretion of antidiuretic hormone and oxytocin Emotional and behavioral drives and thirst drives Coordination between voluntary and autonomic functions Body temperature Circadian rhythm © 2015 Pearson Education, Inc. 74

Figure 16.12b The Hypothalamus
Enlarged view of the hypothalamus showing the locations of major nuclei and centers. Thalamus Paraventricular nucleus Preoptic area Tuberal area Hypothalamus Sympathetic Optic chiasm Parasympathetic Tuberal nuclei Infundibulum Posterior lobe of pituitary gland Mamillary bodies Suprachiasmatic nucleus Pars distalis Pons Anterior lobe of pituitary gland Pars intermedia Supraoptic nucleus © 2015 Pearson Education, Inc.

The Cerebellum The Cerebellum consists of: Two hemispheres
Folia cerebelli Folds similar to gyri of the cerebrum Anterior and posterior lobes Vermis (separates the hemispheres) Flocculonodular lobes Arbor vitae Cerebellar peduncles © 2015 Pearson Education, Inc. 76

Figure 16.15a The Cerebellum
Vermis Anterior lobe Primary fissure Posterior lobe Folia Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum a Superior surface of the cerebellum. This view shows major anatomical landmarks and regions. © 2015 Pearson Education, Inc.

Figure 16.15b The Cerebellum (2 of 3)
Dendrites projecting into the gray matter of the cerebellum Cell body of Purkinje cell Axons of Purkinje cells projecting into the white matter of the cerebellum Purkinje cells LM  120 b Sagittal view of the cerebellum showing the arrangement of gray matter and white matter. Purkinje cells are seen in the photomicrograph; these large neurons are found in the cerebellar cortex. © 2015 Pearson Education, Inc.

The Cerebellum The Cerebellum Cerebellar cortex Arbor vitae
Subconscious coordination of movements Arbor vitae Connects cerebellar cortex with cerebellar peduncles Cerebellar peduncles Superior: connect cerebellum with mesencephalon, diencephalon, and cerebrum Middle: communicate between cerebellum and pons Inferior: connect cerebellum with the medulla oblongata © 2015 Pearson Education, Inc. 80

The Cerebrum The cerebrum consists of: Two hemispheres Several lobes
Frontal, parietal, occipital, and temporal Gyri and sulci Longitudinal fissure Corpus callosum Basal nuclei Limbic system © 2015 Pearson Education, Inc. 81

Figure 16.16a The Cerebral Hemispheres, Part I
ANTERIOR Longitudinal fissure Right cerebral hemisphere Left cerebral hemisphere Cerebral veins and arteries covered by arachnoid mater Central sulcus Parieto-occipital sulcus Cerebellum POSTERIOR a Superior view. © 2015 Pearson Education, Inc.

Figure 16.21c The Basal Nuclei
Corpus callosum Lateral ventricle Caudate nucleus Septum pellucidum Putamen Insula Globus pallidus Lateral sulcus Internal capsule Claustrum Anterior commissure Amygdaloid body Tip of inferior horn of lateral ventricle c Frontal section © 2015 Pearson Education, Inc.

The Cerebrum The Cerebral Hemispheres The hemispheres consist of:
Gyri and sulci Central sulcus Longitudinal fissure Cerebral lobes Lateral sulcus © 2015 Pearson Education, Inc. 84

The Cerebrum The Cerebral Hemispheres The cerebral lobes Frontal lobe
Conscious control of skeletal muscles Occipital lobe Perception of visual stimuli Parietal lobe Conscious perception of touch, pressure, vibration, pain, temperature, and taste Temporal lobe Conscious perception of auditory and olfactory stimuli © 2015 Pearson Education, Inc. 85

Figure 16.17b The Cerebral Hemispheres, Part II
Precentral gyrus Postcentral gyrus Parietal Lobe Central sulcus Frontal lobe of left cerebral hemisphere Lateral sulcus Occipital lobe Branches of middle cerebral artery emerging from lateral sulcus Cerebellum Temporal lobe Pons b Lateral view of intact brain after removal of the dura mater and arachnoid mater showing superficial surface anatomy of the left hemisphere. Medulla oblongata © 2015 Pearson Education, Inc.

The Cerebrum The Insula Lies deep to the lateral sulcus
Consists of olfactory cortex and gustatory cortex © 2015 Pearson Education, Inc. 87

Figure 16.17a The Cerebral Hemispheres, Part II
Central sulcus Frontal Lobe (retracted to show insula) Parietal Lobe Primary sensory cortex (postcentral gyrus) Primary motor cortex (precentral gyrus) Somatic motor association area (premotor cortex) Somatic sensory association area Retractor Occipital Lobe Visual association area Prefrontal cortex Visual cortex Gustatory cortex Insula Temporal Lobe (retracted to show olfactory cortex) Lateral sulcus Auditory association area a Major anatomical landmarks on the surface of the left cerebral hemisphere. To expose the insula, the lateral sulcus has been pulled open. Auditory cortex Olfactory cortex © 2015 Pearson Education, Inc.

The Cerebrum Motor and Sensory Areas of the Cerebral Cortex
Precentral gyrus Anterior to the central sulcus Neurons direct voluntary movements by controlling somatic motor neurons in the brain stem and spinal cord Postcentral gyrus Posterior to the central sulcus Neurons receive somatic sensory information for touch, pressure, pain, taste, and temperature from the dorsal columns and spinothalamic tracts © 2015 Pearson Education, Inc. 89

Figure 16.17b The Cerebral Hemispheres, Part II
Precentral gyrus Postcentral gyrus Parietal Lobe Central sulcus Frontal lobe of left cerebral hemisphere Lateral sulcus Occipital lobe Branches of middle cerebral artery emerging from lateral sulcus Cerebellum Temporal lobe Pons b Lateral view of intact brain after removal of the dura mater and arachnoid mater showing superficial surface anatomy of the left hemisphere. Medulla oblongata © 2015 Pearson Education, Inc.

The Cerebrum Higher-Order Functions
Characteristics of higher-order functions They are performed by the cerebral cortex They involve communication between cerebral cortex areas and other areas of the brain They involve conscious and unconscious information processing The functions are subject to modifications and adjustments © 2015 Pearson Education, Inc. 91

The Cerebrum Integrative Regions of the Cerebral Cortex
The centers of the various regions of the cerebral cortex do the following: Integrate complex sensory stimuli Integrate complex motor responses The various centers are: General interpretive area The speech center The prefrontal cortex Brodmann’s areas © 2015 Pearson Education, Inc. 92

Figure 16.18a Integrative Regions of the Cerebral Cortex
Speech center (Broca’s area) Frontal eye field General interpretive area (gnostic area) Prefrontal association cortex a Higher-order integrative regions of the cerebral cortex © 2015 Pearson Education, Inc.

Figure 16.18b Integrative Regions of the Cerebral Cortex
4 6 1 40 39 44 41 42 18 17 b Selected Brodmann’s areas of the cerebral cortex © 2015 Pearson Education, Inc.

The general interpretive area Found only in one hemisphere, usually the left Analytical center The speech center Also called Broca’s area A motor center that regulates patterns of breathing and vocalization for speech © 2015 Pearson Education, Inc. 95

The prefrontal cortex Performs complicated learning and reasoning functions Brodmann’s areas and cortical function Assigned numbers to various brain regions by analyzing each area's cellular structure Perhaps the various cellular structures can correlate with specific functions © 2015 Pearson Education, Inc. 96

The Cerebrum Hemispheric Specialization Left hemisphere
Speech center, writing, language, mathematics Right hemisphere Analysis by touch, spatial visualization © 2015 Pearson Education, Inc. 97

Figure 16.19 Hemispheric Specialization
Left Cerebral Hemisphere Right Cerebral Hemisphere LEFT HAND RIGHT HAND Prefrontal cortex Prefrontal cortex Speech center Anterior commissure C O R P Writing U Analysis by touch S C Auditory cortex (right ear) A Auditory cortex (left ear) L L O S General interpretive center (language and mathematical calculation) U Spatial visualization and analysis M Visual cortex (right visual field) Visual cortex (left visual field) © 2015 Pearson Education, Inc.

The Cerebrum The Central White Matter Consists of bundles called:
Association fibers Tracts that interconnect areas of neural cortex within a hemisphere (arcuate fibers and longitudinal fasciculi) Commissural fibers Tracts that connect the two hemispheres (anterior commissure and corpus callosum) Projection fibers Tracts that link the cerebrum with other regions of the brain and spinal cord © 2015 Pearson Education, Inc. 99

Figure 16.20a The Central White Matter
Arcuate fibers Longitudinal fasciculi a Lateral aspect of the brain showing arcuate fibers and longitudinal fasciculi © 2015 Pearson Education, Inc.

Figure 16.20b The Central White Matter
Corpus callosum Longitudinal fissure Anterior commissure Projection fibers Internal capsule b Anterior view of the brain showing orientation of the commissural and projection fibers © 2015 Pearson Education, Inc.

The Cerebrum The Basal Nuclei
These are masses of gray matter embedded in the white matter inferior to the lateral ventricles General function: Involved with subconscious control and integration of skeletal muscle tone Involved with the coordination of learned movement patterns Involved in the processing, integration, and relay of information from the cerebral cortex © 2015 Pearson Education, Inc. 102

The Cerebrum The Basal Nuclei Consist of: Caudate nucleus
Amygdaloid body Claustrum Putamen Globus pallidus © 2015 Pearson Education, Inc. 103

Figure 16.21c The Basal Nuclei
Corpus callosum Lateral ventricle Caudate nucleus Septum pellucidum Putamen Insula Globus pallidus Lateral sulcus Internal capsule Claustrum Anterior commissure Amygdaloid body Tip of inferior horn of lateral ventricle c Frontal section © 2015 Pearson Education, Inc.

The Cerebrum The Basal Nuclei
Caudate nucleus, putamen, and globus pallidus Control the cycles of arm and leg movements when walking Claustrum Plays a role in subconscious processing of visual information Amygdaloid body Component of the limbic system © 2015 Pearson Education, Inc. 105

The Cerebrum The Limbic System
Located between the cerebrum and the diencephalon just superior to the corpus callosum Functions: Establishes emotional states Links the conscious functions with the unconscious autonomic functions Facilitates memory storage and retrieval © 2015 Pearson Education, Inc. 106

Figure 16.22a The Limbic System
Interthalamic adhesion Central sulcus Cingulate gyrus (limbic lobe) Fornix Pineal gland Corpus callosum Thalamus Hypothalamus Temporal lobe Parahippocampal gyrus (limbic lobe) Hippocampus (within dentate gyrus) Mamillary body a Sagittal section through the cerebrum showing the cortical areas associated with the limbic system. The parahippocampal and dentate gyri are shown as if transparent so that deeper limbic components can be seen. © 2015 Pearson Education, Inc.

The Cerebrum The limbic system consists of: Cingulate gyrus
Dentate gyrus Parahippocampal gyrus Hippocampus © 2015 Pearson Education, Inc. 108

Figure 16.22b The Limbic System
Corpus callosum Cingulate gyrus Fornix Anterior nucleus of thalamus Hypothalamic nuclei Olfactory tract Amygdaloid body Mamillary body Hippocampus (within dentate gyrus) Parahippocampal gyrus b Additional details concerning the three-dimensional structure of the limbic system. © 2015 Pearson Education, Inc.

The Cerebrum The Limbic System The fornix
Tract of white matter connecting the hippocampus with the hypothalamus Many fornix fibers extend to the mamillary bodies Mamillary bodies control reflex movements associated with eating © 2015 Pearson Education, Inc. 110

Figure 16.22b The Limbic System
Corpus callosum Cingulate gyrus Fornix Anterior nucleus of thalamus Hypothalamic nuclei Olfactory tract Amygdaloid body Mamillary body Hippocampus (within dentate gyrus) Parahippocampal gyrus b Additional details concerning the three-dimensional structure of the limbic system. © 2015 Pearson Education, Inc.

The Cranial Nerves There are 12 pairs of cranial nerves
These nerves innervate the periphery emerging from the brain (not the spinal cord) These nerves are on the ventrolateral surface of the brain They are numbered beginning at the anterior aspect of the brain They are numbered CN I to CN XII © 2015 Pearson Education, Inc. 112

Figure 16.23b Origins of the Cranial Nerves
Olfactory bulb, termination of olfactory nerve (N I) Olfactory tract Optic chiasm Optic nerve (N II) Infundibulum Oculomotor nerve (N III) Trochlear nerve (N IV) Trigeminal nerve (N V) Abducens nerve (N VI) Facial nerve (N VII) Vestibulocochlear nerve (N VIII) Glossopharyngeal nerve (N IX) Vagus nerve (N X) Hypoglossal nerve (N XII) Accessory nerve (N XI) b Diagrammatic inferior view of the human brain. Compare view with part (a). © 2015 Pearson Education, Inc.

Figure 16.23a Origins of the Cranial Nerves
Olfactory bulb, termination of olfactory nerve (N I) Olfactory tract Mamillary body Optic chiasm Optic nerve (N II) Basilar artery Infundibulum Oculomotor nerve (N III) Pons Trochlear nerve (N IV) Trigeminal nerve (N V) Abducens nerve (N VI) Facial nerve (N VII) Vestibulocochlear nerve (N VIII) Vertebral artery Glossopharyngeal nerve (N IX) Cerebellum Vagus nerve (N X) Medulla oblongata Hypoglossal nerve (N XII) Spinal cord Accessory nerve (N XI) a The inferior surface of the brain as it appears on gross dissection. The roots of the cranial nerves are clearly visible. © 2015 Pearson Education, Inc.

The Cranial Nerves CN I: The Olfactory Nerve Function Origin Foramen
Sensory (smell) Origin Olfactory epithelium Foramen Olfactory foramina Destination Olfactory bulbs © 2015 Pearson Education, Inc. 115

Figure 16.24 The Olfactory Nerve
Left olfactory bulb (termination of olfactory nerve) Olfactory tract (to olfactory cortex of cerebrum) OLFACTORY NERVE (N I) Olfactory nerve fibers Cribriform plate of ethmoid Olfactory epithelium © 2015 Pearson Education, Inc.

The Cranial Nerves CN II: The Optic Nerve Function Origin Foramen
Sensory (vision) Origin Retina Foramen Optic canal Destinatio Diencephalon, then to occipital lobe © 2015 Pearson Education, Inc. 117

Eye Visual cortex (in occipital lobes)
Figure The Optic Nerve Eye Olfactory bulb OPTIC NERVE (N II) Olfactory tract Optic chiasm Pituitary gland Optic tract Mesencephalon (cut) Lateral geniculate nucleus (in thalamus) Optic projection fibers Visual cortex (in occipital lobes) © 2015 Pearson Education, Inc.

The Cranial Nerves CN III: The Oculomotor Nerve
Function: controls extra-ocular eye muscles Motor function Superior, inferior, medial rectus, inferior oblique Levator palpebrae superioris Origin Mesencephalon Foramen Superior orbital fissure Destination Extra-ocular eye muscles © 2015 Pearson Education, Inc. 119

Figure 16.26 Cranial Nerves Controlling the Extra-Ocular Muscles
Superior rectus muscle OPTIC NERVE (N II) Optic chiasm OCULOMOTOR NERVE (N III) TROCHLEAR NERVE (N IV) Superior oblique muscle Trochlea Levator palpebrae superioris muscle Trigeminal nerve (N V), cut Inferior oblique muscle Vestibulocochlear nerve (N VIII), cut Facial nerve (N VII), cut Inferior rectus muscle Medial rectus muscle ABDUCENS NERVE (N VI) Lateral rectus muscle (cut) Ciliary ganglion © 2015 Pearson Education, Inc.

The Cranial Nerves CN IV: The Trochlear Nerve Function Origin Foramen
Controls extra-ocular eye muscles Motor function Superior oblique Origin Mesencephalon Foramen Superior orbital fissure Destination Superior oblique muscle © 2015 Pearson Education, Inc. 121

The Cranial Nerves CN V: The Trigeminal Nerve Function Origin
Mixed (sensory and motor) function Ophthalmic: sensations from the forehead, eyelids, and nose Maxillary: sensations from lower eyelid, upper lip, and cheek Mandibular: controls mastication Origin Ophthalmic, maxillary, and mandibular nerves © 2015 Pearson Education, Inc. 123

Figure 16.27 The Trigeminal Nerve
Superior orbital fissure Ophthalmic branch Semilunar ganglion Supraorbital nerves Ciliary ganglion Pons TRIGEMINAL NERVE (N V) Foramen rotundum Maxillary branch Infra-orbital nerve Foramen ovale Lingual nerve Otic ganglion Mandibular branch Mental nerve Pterygopalatine ganglion Submandibular ganglion © 2015 Pearson Education, Inc.

The Cranial Nerves CN V: The Trigeminal Nerve (continued) Foramen
Ophthalmic: superior orbital fissure Maxillary: foramen rotundum Mandibular: foramen ovale Destination Ophthalmic and maxillary: Pons Mandibular: mandibular muscles © 2015 Pearson Education, Inc. 125

The Cranial Nerves CN VI: The Abducens Nerve Function Origin Foramen
Controls eye movements Motor function Origin Pons Foramen Superior orbital fissure Destination Innervates the lateral rectus eye muscle © 2015 Pearson Education, Inc. 126

The Cranial Nerves CN VII: The Facial Nerve Function Origin
Mixed (sensory and motor) Sensory: sensations from the face/taste Motor: controls muscles of the face Origin Sensory: taste buds Motor: pons © 2015 Pearson Education, Inc. 128

The Cranial Nerves CN VII: The Facial Nerve Foramen Destination
Internal acoustic meatus Destination Sensory: pons Motor: muscles of the face © 2015 Pearson Education, Inc. 129

Figure 16.28a The Facial Nerve
Pterygopalatine ganglion Greater petrosal nerve Geniculate ganglion FACIAL NERVE (N VII) Temporal branch Pons Zygomatic branches Posterior auricular branch Stylomastoid foramen Buccal branch Chorda tympani nerve (with mandibular branch of N V) Mandibular branch Lingual branch (with lingual nerve of N V) Cervical branch Submandibular ganglion a Origin and branches of the facial nerve © 2015 Pearson Education, Inc.

The Cranial Nerves CN VIII: The Vestibulocochlear Nerve Function
Sensory: balance and hearing Origin Receptors of the vestibule and cochlea Foramen Internal acoustic meatus Destination Pons © 2015 Pearson Education, Inc. 131

Figure 16.29 The Vestibulocochlear Nerve (1 of 1)
Tympanic cavity (middle ear) Semicircular canals Vestibular branch (N VIII) Facial nerve (N VII), cut Internal acoustic canal VESTIBULOCOCHLEAR NERVE (N VIII) N V Pons N VI N VII N IX N XII N X Medulla oblongata N XI Tympanic membrane Auditory tube Cochlea Cochlear branch (N VIII) © 2015 Pearson Education, Inc.

The Cranial Nerves CN IX: The Glossopharyngeal Nerve Function Origin
Mixed (sensory and motor) Sensory function: tongue pain Motor function: swallowing Origin Sensory: posterior 1/3 of the tongue Motor: salivary gland © 2015 Pearson Education, Inc. 133

The Cranial Nerves CN IX: The Glossopharyngeal Nerve (continued)
Foramen Jugular foramen Destination Sensory: medulla oblongata Visceral motor: parotid salivary gland Somatic motor: pharyngeal muscles for swallowing © 2015 Pearson Education, Inc. 134

Figure 16.30 The Glossopharyngeal Nerve
N V Pons N VIII N VII GLOSSOPHARYNGEAL NERVE (N IX) Otic ganglion N VI Medulla oblongata Inferior (petrosal) ganglion Superior (jugular) ganglion Pharyngeal branches Lingual branch Parotid salivary gland Carotid sinus branch Carotid body Carotid sinus Common carotid artery © 2015 Pearson Education, Inc.

The Cranial Nerves CN X: The Vagus Nerve Function Origin
Sensory: information from organs Motor: sends information to the organs Origin Sensory: from the organs Motor: medulla oblongata © 2015 Pearson Education, Inc. 136

The Cranial Nerves CN X: The Vagus Nerve (continued) Foramen
Jugular foramen Destination Sensory: autonomic centers of the medulla oblongata Somatic motor: muscles of the palate and pharynx Visceral motor: respiratory, cardiovascular, and digestive organs © 2015 Pearson Education, Inc. 137

© 2015 Pearson Education, Inc.
Figure The Vagus Nerve VAGUS NERVE (N X) Pons Superior pharyngeal branch Medulla oblongata Auricular branch to external ear Superior ganglion of vagus nerve Inferior ganglion of vagus nerve Pharyngeal branch Superior laryngeal nerve Internal branch Superior laryngeal nerve External branch Recurrent laryngeal nerve Cardiac branches Cardiac plexus Right lung Left lung Liver Anterior vagal trunk Stomach Spleen Celiac plexus Pancreas Colon Small intestine Hypogastric plexus © 2015 Pearson Education, Inc.

The Cranial Nerves CN XI: The Accessory Nerve Function Origin
Motor: controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles Origin Spinal cord and medulla oblongata © 2015 Pearson Education, Inc. 139

The Cranial Nerves CN XI: The Accessory Nerve Foramen Destination
Jugular foramen Destination Internal branch: muscles of the palate, pharynx, and larynx External branch: sternocleidomastoid and trapezius muscles © 2015 Pearson Education, Inc. 140

Figure 16.32 The Accessory and Hypoglossal Nerves
HYPOGLOSSAL NERVE (N XII) Trigeminal nerve (N V) ACCESSORY NERVE (N XI) Medulla oblongata Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve Cranial root of N XI Intrinsic muscles of tongue Spinal root of N XI Styloglossus muscle External branch of N XI Genioglossus muscle Geniohyoid muscle Spinal cord Hyoglossus muscle Hyoid bone Trapezius muscle Thyrohyoid muscle Sternocleidomastoid muscle Sternohyoid muscle Ansa cervicalis (cervical plexus) Sternothyroid muscle Omohyoid muscle © 2015 Pearson Education, Inc.

The Cranial Nerves CN XII: The Hypoglossal Nerve Function Origin
Motor: controls tongue movement Origin Medulla oblongata Foramen Hypoglossal canal Destination Tongue muscles © 2015 Pearson Education, Inc. 142

Figure 16.32 The Accessory and Hypoglossal Nerves
HYPOGLOSSAL NERVE (N XII) Trigeminal nerve (N V) ACCESSORY NERVE (N XI) Medulla oblongata Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve Cranial root of N XI Intrinsic muscles of tongue Spinal root of N XI Styloglossus muscle External branch of N XI Genioglossus muscle Geniohyoid muscle Spinal cord Hyoglossus muscle Hyoid bone Trapezius muscle Thyrohyoid muscle Sternocleidomastoid muscle Sternohyoid muscle Ansa cervicalis (cervical plexus) Sternothyroid muscle Omohyoid muscle © 2015 Pearson Education, Inc.

The Cranial Nerves Summary of Cranial Nerve Branches and Functions
Mnemonic aid Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly © 2015 Pearson Education, Inc. 144

Table 16.12 The Cranial Nerves (1 of 2)

Table 16.12 The Cranial Nerves (2 of 2)

Table 16.13 Cranial Reflexes

© 2015 Pearson Education, Inc.

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