Chapter 14 The Brain and Cranial Nerves Lecture

An Introduction to the Brain and Cranial Nerves • The Adult Human Brain • Volume ranges from 750 m. L to 2100 m. L • Contains almost 97 percent of the body’s neural tissue • Average weight about 1. 4 kg (3 lb) © 2015 Pearson Education, Inc.

14 -1 The Brain • Six Regions of the Brain 1. 2. 3. 4.

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) © 2015 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) © 2015 Pearson Education, Inc.

14 -1 The Brain • Cerebellum • • Second largest part of brain Coordinates

Figure 14 -1 An Introduction to Brain Structures and Functions (Part 1 of 2). Left cerebral hemisphere Gyri Sulci Cerebrum • Conscious thought processes, intellectual functions • Memory storage and processing • Conscious and subconscious regulation of skeletal muscle contractions Fissures Cerebellum Spinal cord © 2015 Pearson Education, Inc. • Coordinates complex somatic motor patterns • Adjusts output of other somatic motor centers in brain and spinal cord

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 © 2015 Pearson Education, Inc.

14 -1 The Brain • Diencephalon • Thalamus • Relays and processes sensory information

14 -1 The Brain • Diencephalon • Pituitary gland • • Major endocrine gland

14 -1 The Brain • The Brain Stem • Processes information between: • Spinal

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 © 2015 Pearson Education, Inc.

14 -1 The Brain • Medulla Oblongata • Connects brain to spinal cord •

Figure 14 -1 An Introduction to Brain Structures and Functions (Part 2 of 2). Diencephalon Thalamus • Relay and processing centers for sensory information Hypothalamus • Centers controlling emotions, autonomic functions, and hormone production Midbrain Brain stem • Processing of visual and auditory date • Generation of reflexive somatic motor responses • Maintenance of consciousness Pons • Relays sensory information to cerebellum and thalamus • Subconscious somatic and visceral motor centers © 2015 Pearson Education, Inc. 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)

14 -1 The Brain • Embryonic Development • Determines organization of brain structures • Neural tube • Origin of brain • Enlarges into three primary brain vesicles 1. 2. 3. © 2015 Pearson Education, Inc. Prosencephalon Mesencephalon Rhombencephalon

14 -1 The Brain • Five Secondary Brain Vesicles 1. 2. 3. 4. 5.

14 -1 The Brain • Origins of Brain Structures • Diencephalon and mesencephalon persist • Telencephalon • Becomes cerebrum • Metencephalon • Forms cerebellum and pons • Myelencephalon • Becomes medulla oblongata © 2015 Pearson Education, Inc.

Table 14 -1 Development of the Brain. © 2015 Pearson Education, Inc.

14 -1 The Brain • Ventricles of the Brain • Origins of ventricles • Neural tube encloses neurocoel • Neurocoel expands to form chambers (ventricles) lined with ependyma • Each cerebral hemisphere contains one large lateral ventricle • Separated by a thin medial partition (septum pellucidum) © 2015 Pearson Education, Inc.

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) © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

Figure 14 -2 a Ventricles of the Brain Cerebral hemispheres Lateral ventricles Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Pons Medulla oblongata Spinal cord Central canal a Ventricles, lateral view © 2015 Pearson Education, Inc.

Figure 14 -2 b Ventricles of the Brain Cerebral hemispheres Lateral ventricles Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Central canal Cerebellum b Ventricles, anterior view © 2015 Pearson Education, Inc.

14 -1 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 © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Physical Protection of the Brain • Bones of the cranium • Cranial meninges • Cerebrospinal fluid • Biochemical Isolation • Blood–brain barrier © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • The Cranial Meninges • Dura mater • Inner fibrous layer (meningeal layer) • Outer fibrous layer (periosteal layer) fused to periosteum • Venous sinuses between two layers © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Dural Folds • • • Folded inner layer of dura mater Extend into cranial cavity Stabilize and support brain Contain collecting veins (dural sinuses) Three largest dural folds 1. Falx cerebri 2. Tentorium cerebelli 3. Falx cerebelli © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Falx Cerebri • Projects between the cerebral hemispheres • Contains superior sagittal sinus and inferior sagittal sinus • Tentorium Cerebelli • Separates cerebellum and cerebrum • Contains transverse sinus • Falx Cerebelli • Divides cerebellar hemispheres below the tentorium cerebelli © 2015 Pearson Education, Inc.

Figure 14 -3 a The Relationship among the Brain, Cranium, and Cranial Meninges. Cranium Dura mater (periosteal layer) Dural sinus Dura mater (meningeal layer) Subarachnoid space Pia mater Subdural space Cerebral cortex Arachnoid mater Cerebrum Cerebellum Medulla oblongata Spinal cord a A lateral view of the brain, showing its position in the cranium and the organization of the meninges © 2015 Pearson Education, Inc.

Figure 14 -3 b The Relationship among the Brain, Cranium, and Cranial Meninges. Dura mater Superior sagittal sinus Cranium Inferior sagittal sinus Dural folds Falx cerebri Tentorium cerebelli Falx cerebelli Transverse sinus b A diagrammatic view, showing the orientation of the three largest dural folds: the falx cerebri, tentorium cerebelli, and falx cerebelli © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Cerebrospinal Fluid (CSF) • Choroid plexus • Specialized ependymal cells and capillaries • Secrete CSF into ventricles • Remove waste products from CSF • Adjust composition of CSF • Produces about 500 m. L of CSF/day © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

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 • Arachnoid granulations • Large clusters of villi • Absorb CSF into venous circulation © 2015 Pearson Education, Inc.

Figure 14 -4 Formation and Circulation of Cerebrospinal Fluid (Part 2 of 3). Choroid plexus of third ventricle Choroid plexus of fourth ventricle 2 The CSF circulates from the choroid plexuses through the ventricles and fills the central canal of the spinal cord. As it circulates, materials diffuse between the CSF and the interstitial fluid of the CNS across the ependymal cells. 3 The CSF reaches the subarachnoid space through two lateral apertures and a single median aperture in the roof of the fourth ventricle. Spinal cord Central canal Dura mater Cauda equina Arachnoid mater Filum terminale © 2015 Pearson Education, Inc. 4 Cerebrospinal fluid then flows through the subarachnoid space surrounding the brain, spinal cord, and cauda equina.

Figure 14 -4 Formation and Circulation of Cerebrospinal Fluid (Part 1 of 3). Nutrients, O 2 Interstitial Fluid in thalamus Capillaries Waste products, CO 2 Neuron Astrocyte 1 Choroid plexus ependymal cells Ependymal cells The choroid plexus produces and maintains CSF. Two extensive folds of the choroid plexus originate in the roof of the third ventricle and extend through the interventricular foramina. These folds cover the floors of the lateral ventricles. In the inferior brain stem, a region of the choroid plexus in the roof of the fourth ventricle projects between the cerebellum and the pons. Removal of waste Production of CSF Tight junction Choroid plexus © 2015 Pearson Education, Inc. Cerebrospinal Fluid in third ventricle

Figure 14 -4 Formation and Circulation of Cerebrospinal Fluid (Part 3 of 3). Dura mater Arachnoid (periosteal layer) granulation trabecula Cranium Superior sagittal sinus CSF fluid movement Dura mater (meningeal layer) Subdural space Arachnoid mater Cerebral cortex 5 Subarachnoid space Pia mater Fingerlike extensions of the arachnoid membrane, called the arachnoid villi, penetrate the meningeal layer of the dura mater and extend into the superior sagittal sinus. In adults, these extensions form large arachnoid granulations. CSF is absorbed into the venous circulation at the arachnoid granulations. © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Blood–Brain Barrier (BBB) • Isolates CNS neural tissue from general circulation • Formed by network of tight junctions • Between endothelial cells of CNS capillaries • Lipid-soluble compounds (O 2, CO 2), steroids, and prostaglandins • Diffuse into interstitial fluid of brain and spinal cord • Astrocytes control blood–brain barrier by: • Releasing chemicals that control permeability of endothelium © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Blood–CSF Barrier • • Formed by special ependymal cells Surrounds capillaries of choroid plexus Limits movement of compounds transferred Allows chemical composition of blood and CSF to differ © 2015 Pearson Education, Inc.

14 -2 Brain Protection and Support • Four Breaks in the BBB 1. Portions of hypothalamus • Secrete hypothalamic hormones 2. Posterior lobe of pituitary gland • Secretes hormones ADH and oxytocin 3. Pineal gland • Pineal secretions 4. Choroid plexus • Where special ependymal cells maintain blood– CSF barrier © 2015 Pearson Education, Inc.

14 -3 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 © 2015 Pearson Education, Inc.

Figure 14 -5 a The Diencephalon and Brain Stem. Diencephalon Cerebral peduncle Lateral geniculate nucleus Thalamus Optic tract Medial geniculate nucleus Cranial nerves Midbrain N II Superior colliculus Inferior colliculus N III N IV Cerebellar peduncles Superior cerebellar peduncle NV Pons N VIII N IX NX N XI Middle cerebellar peduncle Inferior cerebellar peduncle Medulla oblongata N XII Spinal nerve C 1 Spinal nerve C 2 Spinal cord a Lateral view © 2015 Pearson Education, Inc.

Figure 14 -5 b The Diencephalon and Brain Stem. Optic chiasm Thalamus Infundibulum Cranial nerves N II Optic tract N III Cerebral peduncle N IV Mammillary body Pons NV N VIII N IX NX N XII Medulla oblongata Ventral roots of spinal nerves C 1 and C 2 Spinal cord © 2015 Pearson Education, Inc. b Anterior view

Figure 14 -5 c The Diencephalon and Brain Stem. Thalamus Choroid plexus in third and fourth ventricles Third ventricle Pineal gland Corpora quadrigemina Superior colliculi Inferior colliculi N IV Cerebral peduncle Cerebellar peduncles Superior Middle Choroid plexus in roof of fourth ventricle Inferior Dorsal roots of spinal nerves C 1 and C 2 © 2015 Pearson Education, Inc. c Posterior view

Figure 14 -5 d The Diencephalon and Brain Stem. Thalamus Third ventricle Pineal gland Corpora quadrigemina Superior colliculi Inferior colliculi Cerebral peduncle Cerebellar peduncles Superior Trochlear nerve (N IV) Middle Inferior Fourth ventricle © 2015 Pearson Education, Inc. d Posterior view, cadaver dissection

14 -3 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 © 2015 Pearson Education, Inc.

14 -3 The Medulla Oblongata • Autonomic Nuclei of the Medulla Oblongata • Reticular

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 © 2015 Pearson Education, Inc.

14 -3 The Medulla Oblongata • Sensory and Motor Nuclei of the Medulla Oblongata

14 -3 The Medulla Oblongata • Relay Stations of the Medulla Oblongata • Nucleus gracilis and nucleus cuneatus • Pass somatic sensory information to thalamus • Solitary nucleus • Receives visceral sensory information • Olivary nuclei (olives) • Relay information about somatic motor commands © 2015 Pearson Education, Inc.

Figure 14 -6 a The Medulla Oblongata. Autonomic centers Reticular formation Cardiovascular centers Medulla oblongata Solitary nucleus Pons Relay stations Olivary nucleus Nucleus cuneatus Olive Pyramids Decussation of pyramids © 2015 Pearson Education, Inc. Spinal cord a Anterior view Nucleus gracilis Lateral white columns

Figure 14 -6 b The Medulla Oblongata Region/Nucleus Function GRAY MATTER Attachment to membranous roof of fourth ventricle Olivary nucleus Relay information from the red nuclei, other midbrain centers, and the cerebral cortex to the cerebellum Reflex centers Regulate heart rate and force of contraction Set the basic pace of respiratory movements Cardiovascular center Respiratory rhythmicity center Nucleus gracilis Relay somatic information to the thalamus Nucleus cuneatus Posterior median sulcus Other nuclei/centers Cranial nerves VIII (in part), IX, X, XI (in part), and XII Sensory and motor nuclei of five cranial nerves; nuclei relay ascending information from the spinal cord to higher centers Reticular formation Contains nuclei and centers that regulate vital autonomic functions; extends into the pons and midbrain Lateral white column WHITE MATTER Posterior white columns b Posterolateral view © 2015 Pearson Education, Inc. Ascending and descending tracts within columns Link the brain with the spinal cord

14 -4 The Pons • The Pons 1. Sensory and motor nuclei of cranial nerves (V, VII, VIII) 2. Nuclei involved with respiration • Apneustic center and pneumotaxic center • Modify respiratory rhythmicity center activity 3. Nuclei that process and relay information to and from cerebellum 4. Ascending, descending, and transverse tracts • Transverse fibers (axons) • Link nuclei of pons with opposite cerebellar hemisphere © 2015 Pearson Education, Inc.

Figure 14 -7 The Pons Region/Nucleus Function WHITE MATTER Pons Cerebellum Fourth ventricle Medulla oblongata Spinal cord Olivary nucleus © 2015 Pearson Education, Inc. Descending tracts Carry motor commands from higher centers to nuclei of cranial or spinal nerves Ascending tracts Carry sensory information from brain stem nuclei to the thalamus Transverse fibers Interconnect cerebellar hemispheres GRAY MATTER Apneustic and pneumotaxic centers Adjust activities of the respiratory rhythmicity centers in the medulla oblongata Reticular formation Automatic processing of incoming sensations and outgoing motor commands Cranial nerve nuclei N V, VII, and VIII (in part) Relay sensory information and issue somatic motor commands Other nuclei/relay centers Relay sensory and motor Information to the cerebellum

14 -5 The Cerebellum • Functions of the Cerebellum 1. Adjusts postural muscles 2.

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 © 2015 Pearson Education, Inc.

14 -5 The Cerebellum • Structures of the Cerebellum • Vermis • Narrow band

14 -5 The Cerebellum • Structures of the Cerebellum • Purkinje cells • Large, branched cells • Found in cerebellar cortex • Receive input from up to 200, 000 synapses • Arbor vitae (“tree of life”) • Highly branched, internal white matter of cerebellum • Cerebellar nuclei embedded in arbor vitae • Relay information to Purkinje cells © 2015 Pearson Education, Inc.

14 -5 The Cerebellum • Structures of the Cerebellum • The peduncles • Tracts link cerebellum with brain stem, cerebrum, and spinal cord • Superior cerebellar peduncles • Middle cerebellar peduncles • Inferior cerebellar peduncles © 2015 Pearson Education, Inc.

14 -5 The Cerebellum • Disorders of the Cerebellum • Ataxia • Damage from

Figure 14 -8 a The Cerebellum (Part 1 of 2). Vermis Anterior lobe Primary fissure Folia Posterior lobe Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum a The posterior, superior surface of the cerebellum, showing major anatomical landmarks and regions © 2015 Pearson Education, Inc.

Figure 14 -8 a The Cerebellum (Part 2 of 2). Vermis Anterior lobe Primary fissure Folia Posterior lobe Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum a The posterior, superior surface of the cerebellum, showing major anatomical landmarks and regions © 2015 Pearson Education, Inc.

Figure 14 -8 b The Cerebellum (Part 1 of 2). The Cerebellum Region/Nuclei Function GRAY MATTER Anterior lobe Midbrain Pons Choroid plexus of the fourth ventricle Cerebellar cortex Involuntary coordination and control of ongoing body movements Cerebellar nuclei Involuntary coordination and control of ongoing body movements WHITE MATTER Arbor vitae Flocculonodular lobe Connects cerebellar cortex and nuclei with cerebellar peduncles Cerebellar peduncles Medulla oblongata Posterior lobe b A sectional view of the cerebellum, showing the arrangement of gray matter and white matter © 2015 Pearson Education, Inc. Superior Link cerebellum with midbrain, diencephalon, and cerebrum Middle Carry communications between the cerebellum and pons Inferior Link the cerebellum with the medulla oblongata and spinal cord Transverse fibers Interconnect pontine nuclei with the opposite cerebellar hemisphere

Figure 14 -8 b The Cerebellum (Part 2 of 2). Dendrites Cell body of Purkinje cell Axons Purkinje cells LM × 320 b A sectional view of the cerebellum, showing the arrangement of gray matter and white matter © 2015 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) © 2015 Pearson Education, Inc.

14 -6 The Midbrain • Structures of the Midbrain • Cerebral peduncles • Nerve fiber bundles on ventrolateral surfaces • Contain: 1. Descending fibers to cerebellum 2. Motor command fibers © 2015 Pearson Education, Inc.

Figure 14 -9 a The Midbrain Region/Nuclei Function GRAY MATTER Pineal gland Thalamus Tectum (roof) Superior colliculus Inferior colliculus Walls and floor Substantia nigra a A posterior view. The underlying nuclei are colored only on the right. © 2015 Pearson Education, Inc. Integrate visual information with other sensory input; initiate reflex responses to visual stimuli Relay auditory information to medial geniculate nuclei; initiate reflex responses to auditory stimuli Regulates activity in the basal nuclei Red nucleus Subconscious control of upper limb position and background muscle tone Reticular formation Automatic processing of incoming sensations and outgoing motor commands; can initiate involuntary motor responses to stimuli; helps maintain consciousness Other nuclei/centers: Nuclei associated with cranial nerves III and IV WHITE MATTER Cerebral peduncles Connect primary motor cortex with motor neurons in brain and spinal cord; carry ascending sensory information to thalamus

Figure 14 -9 b The Midbrain. Thalamus Corpora quadrigemina Superior colliculi Inferior colliculi Cerebral peduncle Trochlear nerve (N IV) Superior cerebellar peduncle Fourth ventricle b © 2015 Pearson Education, Inc. Posterior view of a cadaver dissection of the diencephalon and brain stem.

Figure 14 -9 c The Midbrain. Cerebral peduncle ANTERIOR Substantia nigra Red nucleus Tegmentum Cerebral aqueduct Superior colliculus Cerebellum Tectum (roof) POSTERIOR c A superior view of a transverse © 2015 Pearson Education, Inc. section at the level of the midbrain.

14 -7 The Diencephalon • Integrates sensory information and motor commands • Thalamus, epithalamus, and hypothalamus • The pineal gland • Found in posterior epithalamus • Secretes hormone melatonin © 2015 Pearson Education, Inc.

14 -7 The Diencephalon • The Thalamus • Filters ascending sensory information for primary

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 © 2015 Pearson Education, Inc.

14 -7 The Diencephalon • The Thalamus • Thalamic nuclei • Are rounded masses

14 -7 The Diencephalon • Five Groups of Thalamic Nuclei 1. Anterior group • Anterior nuclei • Part of limbic system (emotions) 2. Medial group • Provides awareness of emotional states 3. Ventral group • Relays sensory information © 2015 Pearson Education, Inc.

14 -7 The Diencephalon • Five Groups of Thalamic Nuclei 4. Posterior group • Pulvinar nucleus (sensory) • Lateral geniculate nucleus (visual) • Medial geniculate nucleus (auditory) 5. Lateral group • Affects emotional states • Integrates sensory information © 2015 Pearson Education, Inc.

Figure 14 -10 The Thalamus. Frontal lobe Parietal lobe Occipital lobe a A lateral view of the brain, color coded to indicate the regions that receive input from the thalamic nuclei shown in part (b) Limbic system Frontal lobes Anterior group Parietal lobe and cingulate gyrus Association areas of cerebral cortex Medial group Lateral group V e n t r a l g r o u p Posterior group Auditory input Medial geniculate nucleus Basal nuclei Cerebellum © 2015 Pearson Education, Inc. Pulvinar nucleus General Sensory input Visual input Lateral geniculate nucleus b An enlarged view of the thalamic nuclei of the left side

Figure 14 -10 a The Thalamus. Frontal lobe Parietal lobe Occipital lobe a A lateral view of the brain, color coded to indicate the regions that receive input from the thalamic nuclei shown in part (b) © 2015 Pearson Education, Inc.

Figure 14 -10 b The Thalamus. Limbic system Frontal lobes Parietal lobe and cingulate gyrus Anterior group Medial group Association areas of cerebral cortex Lateral group V e n t r a l g r o u p Posterior group Pulvinar nucleus Auditory input Medial geniculate nucleus Basal nuclei Cerebellum General sensory input Visual input Lateral geniculate nucleus b An enlarged view of the thalamic nuclei of the left side © 2015 Pearson Education, Inc.

Table 14 -2 The Thalamus. © 2015 Pearson Education, Inc.

14 -7 The Diencephalon • The Hypothalamus • Mammillary bodies • Process olfactory and other sensory information • Control reflex eating movements • Infundibulum • A narrow stalk • Connects hypothalamus to pituitary gland • Tuberal area • Located between the infundibulum and mammillary bodies • Helps control pituitary gland function © 2015 Pearson Education, Inc.

Figure 14 -11 a The Hypothalamus in Sagittal Section. Parietal lobe Corpus callosum Septum pellucidum Choroid plexus Thalamus (surrounds third ventricle) Fornix Anterior cerebral artery Pineal gland Hypothalamus Frontal lobe Cerebral aqueduct Anterior commissure Cerebellum Optic chiasm Optic nerve a The hypothalamus and adjacent portions of the brain © 2015 Pearson Education, Inc. Fourth ventricle Infundibulum (cut) Tuberal area Mammillary body

Figure 14 -11 b The Hypothalamus in Sagittal Section. Interthalamic adhesion The Hypothalamus Tuberal area Pituitary gland b Paraventricular nucleus Secretes oxytocin, stimulating smooth muscle contractions in uterus and mammary glands Preoptic area Regulates body temperature by control of autonomic centers in the medulla oblongata Autonomic centers Sympathetic Control heart rate and blood pressure by regulation of autonomic centers in the medulla oblongata Parasympathetic Tuberal nucleus Produces inhibitory and releasing hormones that control endocrine cells of the anterior lobe of the pituitary gland (adenohypophysis) Mammillary body Control feeding reflexes (licking, swallowing, etc. ) Suprachiasmatic nucleus Regulates daily (circadian) rhythms Supraoptic nucleus Secretes antidiuretic hormone, restricting water loss by the kidneys Midbrain Pons A diagrammatic view of the hypothalamus, showing the locations and functions of major nuclei and centers © 2015 Pearson Education, Inc. Function Hypothalamus Optic chiasm Infundibulum Region/Nuclei

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 © 2015 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 • Preoptic area of hypothalamus 8. Controls circadian rhythms (day–night cycles) • Suprachiasmatic nucleus © 2015 Pearson Education, Inc.

14 -8 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 © 2015 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 © 2015 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 mammillary body to cingulate gyrus • Reticular formation • Stimulation or inhibition affects emotions (rage, fear, pain, sexual arousal, pleasure) © 2015 Pearson Education, Inc.

Figure 14 -12 a The Limbic System. Corpus callosum Fornix Pineal gland Cingulate gyrus (superior portion of limbic lobe) Anterior group of thalamic nuclei Parahippocampal gyrus (inferior portion of limbic lobe) Hypothalamus Mammillary body Temporal lobe of cerebrum a 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. © 2015 Pearson Education, Inc. Hippocampus (within dentate gyrus)

Figure 14 -12 b The Limbic System Cerebral Components The Limbic System Diencephalic Components Corpus callosum Thalamus Anterior nuclei group Hypothalamus Dentate gyrus Hypothalamic nuclei Tracts Fornix Mammillary body Other Components Reticular formation (not shown) Nuclei Amygdaloid body Olfactory tract b A three-dimensional reconstruction of the limbic system, showing the relationships among the major components. © 2015 Pearson Education, Inc. Limbic lobe cortical areas Cingulate gyrus (superior portion of limbic lobe) Parahippocampal gyrus (inferior portion of limbic lobe) Hippocampus (within dentate gyrus)

14 -9 The Cerebrum • Is the largest part of the brain • Controls

14 -9 The Cerebrum • Gray Matter • In cerebral cortex and basal nuclei

14 -9 The Cerebrum • Structures of the Cerebrum • Gyri of neural cortex • Increase surface area (number of cortical neurons) • Insula (“island” of cortex) • Lies medial to lateral sulcus • Longitudinal fissure • Separates cerebral hemispheres • Lobes • Divisions of hemispheres © 2015 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 © 2015 Pearson Education, Inc.

Figure 14 -13 a The Brain in Lateral View. Central sulcus Frontal lobe Parietal lobe Occipital lobe Lateral sulcus Temporal lobe Pons Medulla oblongata a Lateral view, cadaver brain © 2015 Pearson Education, Inc. Cerebellum

Figure 14 -13 b The Brain in Lateral View. Precentral Central Postcentral gyrus sulcus Frontal lobe Parietal lobe Occipital lobe Temporal lobe Lateral sulcus Cerebellum Pons Medulla oblongata b Lateral view © 2015 Pearson Education, Inc.

Figure 14 -13 c The Brain in Lateral View. Insula c © 2015 Pearson

Figure 14 -13 d The Brain in Lateral View. Precentral gyrus Central sulcus Postcentral gyrus Cingulate gyrus Parietal lobe Frontal lobe Parietooccipital sulcus Occipital lobe Temporal lobe Medulla oblongata d Midsagittal section © 2015 Pearson Education, Inc. Pons Cerebellum

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 © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • White Matter of the Cerebrum • Association fibers • Connections within one hemisphere • Commissural fibers • Bands of fibers connecting two hemispheres • Projection fibers • Connect cerebrum with lower areas © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • Commissural Fibers • Corpus callosum • Anterior commissure ©

14 -9 The Cerebrum • Projection Fibers • Pass through diencephalon • Link cerebral cortex with: • Diencephalon, brain stem, cerebellum, and spinal cord • Internal capsule • All ascending and descending projection fibers © 2015 Pearson Education, Inc.

Figure 14 -14 a Fibers of the White Matter of the Cerebrum a Lateral view © 2015 Pearson Education, Inc. Fibers/Tracts Function Association fibers Interconnect cortical areas within the same hemisphere Arcuate fibers Interconnect gyri within a lobe Longitudinal fasciculi Interconnect the frontal lobe with other cerebral lobes

Figure 14 -14 b Fibers of the White Matter of the Cerebrum Fibers/Tracts Function Commissures Interconnect and permit communication between the cerebral hemispheres Corpus callosum Longitudinal fissure Anterior commissure Projection fibers Internal capsule b Anterior view © 2015 Pearson Education, Inc. Connect cerebral cortex to diencephalon, brain stem, cerebellum, and spinal cord

14 -9 The Cerebrum • The Basal Nuclei • Are masses of gray matter

14 -9 The Cerebrum • Anatomy of Basal Nuclei • Caudate nucleus • Curving,

Figure 14 -15 a The Basal Nuclei. Head of caudate nucleus Lentiform nucleus Tail of caudate nucleus Amygdaloid body a The relative positions of the basal nuclei in the intact brain, lateral view © 2015 Pearson Education, Inc. Thalamus

Figure 14 -15 c The Basal Nuclei Corpus callosum Lateral ventricle Nuclei Function Caudate nucleus Subconscious adjustment and modification of voluntary motor commands Lentiform nucleus Subconscious adjustment and modification of voluntary motor commands Septum pellucidum Internal capsule Putamen Globus pallidus Lateral sulcus Insula Anterior commissure Tip of inferior horn of lateral ventricle c Frontal section © 2015 Pearson Education, Inc. Claustrum Plays a role in the subconscious processing of visual information Amygdaloid body Component of limbic system

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) © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • Motor and Sensory Areas of the Cortex • Central sulcus separates motor and sensory areas • Motor areas • Precentral gyrus of frontal lobe • Directs voluntary movements • Primary motor cortex • Is the surface of precentral gyrus • Pyramidal cells • Are neurons of primary motor cortex © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • Motor and Sensory Areas of the Cortex • Sensory areas • Postcentral gyrus of parietal lobe • Receives somatic sensory information (touch, pressure, pain, vibration, taste, and temperature) • Primary sensory cortex • Surface of postcentral gyrus © 2015 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 © 2015 Pearson Education, Inc.

Figure 14 -16 a Motor and Sensory Regions of the Cerebral Cortex. Central sulcus Parietal Lobe Frontal 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 Lateral sulcus Auditory association area Auditory cortex Olfactory cortex a Major anatomical landmarks on the surface of the left cerebral hemisphere. The lateral sulcus has been pulled apart to expose the insula. © 2015 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) © 2015 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) © 2015 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 © 2015 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) © 2015 Pearson Education, Inc.

Figure 14 -16 b Motor and Sensory Regions of the Cerebral Cortex. Frontal eye field Speech center Prefrontal cortex General interpretive area b 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. © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • Interpretive Areas of Cortex • Brodmann areas • Patterns

Figure 14 -16 c Motor and Sensory Regions of the Cerebral Cortex. 4 6 1 44 41 40 39 42 18 17 c Regions of the cerebral cortex as determined by histological analysis. Several of the 50 Brodmann areas are shown for comparison with the results of functional mapping. © 2015 Pearson Education, Inc.

Table 14 -3 The Cerebral Cortex. © 2015 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 © 2015 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) © 2015 Pearson Education, Inc.

Figure 14 -17 Hemispheric Lateralization (Part 1 of 2). Left Cerebral Hemisphere LEFT HAND Prefrontal cortex Speech center Writing Auditory cortex (right ear) General interpretive center (language and mathematical calculation) Visual cortex (right visual field) © 2015 Pearson Education, Inc. C O R P U S C A L L O S U M

Figure 14 -17 Hemispheric Lateralization (Part 2 of 2). Right Cerebral Hemisphere RIGHT HAND Prefrontal cortex Anterior commissure C O R P U S C A L L O S U M Analysis by touch Auditory cortex (left ear) Spatial visualization and analysis Visual cortex (left visual field) © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • Monitoring Brain Activity • Brain activity is assessed by an electroencephalogram (EEG) • Electrodes are placed on the skull • Patterns of electrical activity (brain waves) are printed out © 2015 Pearson Education, Inc.

14 -9 The Cerebrum • Synchronization • A pacemaker mechanism • Synchronizes electrical activity between hemispheres • Brain damage can cause desynchronization • Seizure • Is a temporary cerebral disorder • Changes the electroencephalogram • Symptoms depend on regions affected © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • 12 pairs connected to brain • Four Classifications of Cranial Nerves 1. Sensory nerves: carriers of somatic sensory information, including touch, pressure, vibration, temperature, and pain 2. Special sensory nerves: carriers of sensations such as smell, sight, hearing, and balance 3. Motor nerves: axons of somatic motor neurons 4. Mixed nerves: mixture of motor and sensory fibers © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • Are classified by primary functions • May also have important secondary functions • Distributing autonomic fibers to peripheral ganglia • The 12 cranial nerve groups are identified by: • • Primary function Origin Pathway Destination © 2015 Pearson Education, Inc.

Figure 14 -19 Origins of the Cranial Nerves (Part 1 of 2). Olfactory bulb: termination of olfactory nerve (N I) Olfactory tract Optic nerve (N II) Infundibulum Oculomotor nerve (N III) Basilar artery Pons Vertebral artery Medulla oblongata Cerebellum Spinal cord © 2015 Pearson Education, Inc.

Figure 14 -19 Origins of the Cranial Nerves (Part 2 of 2). Optic chiasm Optic tract Mammillary body 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) © 2015 Pearson Education, Inc. Accessory nerve (N XI)

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 © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • Olfactory Nerve Structures • Olfactory bulbs • Located on either side of crista galli • Olfactory tracts • Axons of postsynaptic neurons • Leading to cerebrum © 2015 Pearson Education, Inc.

Figure 14 -20 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 Olfactory of ethmoid bone epithelium © 2015 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 © 2015 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 © 2015 Pearson Education, Inc.

Figure 14 -21 The Optic Nerve. Eye Pituitary gland Olfactory bulb Olfactory tract Optic nerve (N II) Optic chiasm Optic tract Lateral geniculate nucleus (in thalamus) Midbrain (cut) © 2015 Pearson Education, Inc. Visual cortex (in occipital lobes) Optic projection fibers

14 -10 Cranial Nerves • Oculomotor Nerves (III) • Primary function: • Motor (eye

14 -10 Cranial Nerves • Oculomotor Nerves (III) • Destination: • Somatic motor • Superior, inferior, and medial rectus muscles • Inferior oblique muscle • Levator palpebrae superioris muscle • Visceral motor • Intrinsic eye muscles © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • Oculomotor Nerve Structures • Oculomotor nerve • Controls four of six eye-movement muscles • Delivers autonomic fibers to ciliary ganglion • Ciliary ganglion controls intrinsic muscles of iris and lens © 2015 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 © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • The Abducens Nerves (VI) • Primary function: • Motor (eye movements) • Origin: • Pons • Pathway: • Superior orbital fissures of sphenoid • Destination: • Lateral rectus muscle © 2015 Pearson Education, Inc.

Figure 14 -22 Cranial Nerves Controlling the Extrinsic Eye Muscles. Superior oblique muscle Superior rectus muscle Optic nerve (N II) Optic chiasm Oculomotor nerve (N III) Trochlear nerve (N IV) Trochlea Levator palpebrae superioris muscle Trigeminal nerve (N V), cut Inferior oblique muscle Vestibulocochlear nerve (N VIII), cut Inferior rectus Ciliary muscle ganglion © 2015 Pearson Education, Inc. Medial rectus muscle Facial nerve (N VII), cut Lateral rectus muscle (cut) Abducens nerve (N VI)

14 -10 Cranial Nerves • The Trigeminal Nerves (V) • Primary function: • Mixed (sensory and motor) to face • Origin: • Ophthalmic branch (sensory) • • © 2015 Pearson Education, Inc. Orbital structures Nasal cavity Skin of forehead, upper eyelid, and eyebrow Part of nose

14 -10 Cranial Nerves • The Trigeminal Nerves (V) • Origin: • Maxillary branch (sensory) • • © 2015 Pearson Education, Inc. Lower eyelid Upper lip, gums, and teeth Cheek and nose Palate and part of pharynx

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 © 2015 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 © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • The Trigeminal Nerves (V) • Destination: • Sensory nerves

14 -10 Cranial Nerves • Trigeminal Nerve Structures • Trigeminal nerves • Largest cranial nerves • With three major branches • Semilunar ganglion • Contains cell bodies of sensory neurons © 2015 Pearson Education, Inc.

Figure 14 -23 The Trigeminal Nerve. Superior orbital fissure Ophthalmic branch Supraorbital nerves Semilunar ganglion Ciliary ganglion Foramen rotundum Pons Trigeminal nerve (N V) Maxillary branch Infraorbital nerve Foramen ovale Lingual nerve Submandibular ganglion Mental nerve © 2015 Pearson Education, Inc. Otic ganglion Mandibular branch Pterygopalatine ganglion

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 nuclei of pons • Pathway: • Internal acoustic meatus to facial canals (stylomastoid foramina) © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • The Facial Nerves (VII) • Destination: • Sensory nuclei of pons • Somatic motor • Muscles of facial expression • Visceral motor • Tear and nasal mucous glands • Submandibular and sublingual salivary glands © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • Facial Nerve Structures • Facial nerve branches • •

Figure 14 -24 a The Facial Nerve. Pterygopalatine Greater petrosal ganglion nerve Geniculate ganglion Facial nerve (N VII) Temporal branch Pons Posterior auricular branch Zygomatic branches Buccal branch Stylomastoid foramen Chorda tympani nerve (with mandibular branch of N V) Mandibular branch Lingual branch (with lingual nerve of N V) Cervical branch a © 2015 Pearson Education, Inc. The origin and branches of the facial nerve Submandibular ganglion

Figure 14 -24 b The Facial Nerve. Temporal branch Zygomatic branch Buccal branch Mandibular branch Cervical branch b © 2015 Pearson Education, Inc. The superficial distribution of the five major branches of the facial nerve

14 -10 Cranial Nerves • The Vestibulocochlear Nerves (VIII) • Primary function: • Special sensory • Vestibular branch • Balance and equilibrium • Cochlear branch • Hearing © 2015 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 © 2015 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 © 2015 Pearson Education, Inc.

Figure 14 -25 The Vestibulocochlear Nerve. Tympanic cavity (middle ear) Semicircular canals Vestibular branch (N VIII) Facial nerve Internal (N VII), cut acoustic meatus Vestibulocochlear nerve (N VIII) NV Pons N VII Medulla oblongata Tympanic membrane © 2015 Pearson Education, Inc. Auditory tube Cochlear branch (N VIII) N IX N XII NX N XI

14 -10 Cranial Nerves • The Glossopharyngeal Nerves (IX) • Primary function: • Mixed

14 -10 Cranial Nerves • The Glossopharyngeal Nerves (IX) • Origins: • Sensory • Posterior 1/3 of tongue • Part of pharynx and palate • Carotid arteries • Motor nuclei of medulla oblongata © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • The Glossopharyngeal Nerves (IX) • Pathway: • Jugular foramina between occipital and temporal bones • Destination: • Sensory nuclei of medulla oblongata • Somatic motor • Nerves involved in swallowing • Visceral motor • Parotid salivary gland © 2015 Pearson Education, Inc.

Figure 14 -26 The Glossopharyngeal Nerve. Pons N VII N VI Otic ganglion NV N VIII Glossopharyngeal nerve (N IX) 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.

14 -10 Cranial Nerves • The Vagus Nerves (X) • Primary function: • Mixed

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 nuclei in medulla oblongata © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • The Vagus Nerves (X) • Pathway: • Jugular foramina

14 -10 Cranial Nerves • The Vagus Nerves (X) • Destination: • 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 © 2015 Pearson Education, Inc.

Figure 14 -27 The Vagus Nerve (Part 1 of 2). Pharyngeal branch Vagus nerve (N X) Pons Medulla oblongata Auricular branch to external ear Inferior ganglion of vagus nerve Superior ganglion of vagus nerve Pharyngeal branch Superior laryngeal nerve Internal branch External branch © 2015 Pearson Education, Inc.

Figure 14 -27 The Vagus Nerve (Part 2 of 2). Cardiac branches Recurrent laryngeal nerve Cardiac plexus Left lung Right lung Liver Anterior vagal trunk Spleen Stomach Celiac plexus Pancreas Colon Small intestine Hypogastric plexus © 2015 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 © 2015 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 © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • Accessory Nerve Structures • Spinal root • Motor fibers that originate in anterior gray horns of first five cervical segments of spinal cord • Cranial root • Motor fibers that originate in medulla oblongata © 2015 Pearson Education, Inc.

14 -10 Cranial Nerves • Accessory Nerve Structures • Internal branch • Joins the

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 © 2015 Pearson Education, Inc.

Figure 14 -28 The Accessory and Hypoglossal Nerves. Hypoglossal nerve (N XII) Accessory nerve (N XI) Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve Trigeminal nerve (N V) Medulla oblongata Cranial root of N XI Spinal root of N XI Intrinsic muscles of tongue 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 Sternothyroid muscle Ansa cervicalis (cervical plexus) Omohyoid muscle © 2015 Pearson Education, Inc.