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Chapter 14 The Brain and Cranial Nerves Lecture Presentation by Lee Ann Frederick University of Texas at Arlington © 2015 Pearson Education, Inc. An Introduction to the Brain and Cranial Nerves • The Adult Human Brain • Volume ranges from 750 mL to 2100 mL • 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. 5. 6. Cerebrum Cerebellum Diencephalon Midbrain Pons Medulla oblongata © 2015 Pearson Education, Inc. 14-1 The Brain • Cerebrum • Largest part of brain • Controls higher mental functions • Divided into left and right cerebral hemispheres • Surface layer of gray matter (neural cortex) © 2015 Pearson Education, Inc. 14-1 The Brain • Cerebellum • Second largest part of brain • Coordinates repetitive body movements • Two hemispheres • Covered with cerebellar cortex © 2015 Pearson Education, Inc. 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 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 • Five Secondary Brain Vesicles 1. 2. 3. 4. 5. Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon © 2015 Pearson Education, Inc. Table 14-1 Development of the Brain. © 2015 Pearson Education, Inc. Figure 14-2a Ventricles of the Brain. 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 14-2b Ventricles of the Brain. 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 • 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. Figure 14-3a 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. 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 mL of CSF/day © 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 3 of 3). Dura mater Arachnoid 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 • 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 (O2, CO2), 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. 14-2 Brain Protection and Support • Protection and Support • Meninges stabilize brain in cranial cavity • Cerebrospinal fluid protects against sudden movement • CSF provides nutrients and removes wastes • Blood–brain barrier and blood–CSF barrier • Selectively isolate brain from chemicals in blood that might disrupt neural function © 2015 Pearson Education, Inc. 14-3 The Medulla Oblongata • The Medulla Oblongata • Allows brain and spinal cord to communicate • Coordinates complex autonomic reflexes • Controls visceral functions • Nuclei in the medulla • Autonomic nuclei control visceral activities • Sensory and motor nuclei of cranial nerves • Relay stations along sensory and motor pathways © 2015 Pearson Education, Inc. Figure 14-5a 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 VI N VII N VIII N IX NX N XI Middle cerebellar peduncle Inferior cerebellar peduncle Medulla oblongata N XII Spinal nerve C1 Spinal nerve C2 © 2015 Pearson Education, Inc. Spinal cord a Lateral view Figure 14-5b 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 VI N VII N VIII N IX NX N XI N XII Medulla oblongata Ventral roots of spinal nerves C1 and C2 Spinal cord © 2015 Pearson Education, Inc. b Anterior view 14-3 The Medulla Oblongata • The Medulla Oblongata • Includes three groups of nuclei 1. Autonomic nuclei 2. Sensory and motor nuclei of cranial nerves 3. Relay stations along sensory and motor pathways © 2015 Pearson Education, Inc. 14-5 The Cerebellum • Functions of the Cerebellum 1. Adjusts postural muscles 2. Fine-tunes conscious and subconscious movements © 2015 Pearson Education, Inc. 14-5 The Cerebellum • Disorders of the Cerebellum • Ataxia • Damage from trauma or stroke • Intoxication (temporary impairment) • Disturbs muscle coordination © 2015 Pearson Education, Inc. Figure 14-8a 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 14-8b 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 14-7 The Diencephalon • The Diencephalon • Integrates sensory information and motor commands • Thalamus, epithalamus, and hypothalamus • The pineal gland • Found in posterior epithalamus • Secretes hormone melatonin © 2015 Pearson Education, Inc. 14-7 The Diencephalon • The Thalamus • Filters ascending sensory information for primary sensory cortex • Relays information between basal nuclei and cerebral cortex © 2015 Pearson Education, Inc. Figure 14-10a 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 14-11b The Hypothalamus in Sagittal Section. Interthalamic adhesion The Hypothalamus Thalamus 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. Figure 14-13d 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. Figure 14-14a Fibers of the White Matter of the Cerebrum. 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 14-14b Fibers of the White Matter of the Cerebrum. 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 Figure 14-15c The Basal Nuclei. 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. Figure 14-16a 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 • Integrative Centers • Are located in lobes and cortical areas of both cerebral hemispheres • Receive information from association areas • Direct complex motor or analytical activities © 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 14-16b 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 of cellular organization in cerebral cortex © 2015 Pearson Education, Inc. Figure 14-16c 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. 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 • Four Categories of Brain Waves 1. 2. 3. 4. Alpha waves Beta waves Theta waves Delta waves © 2015 Pearson Education, Inc. 14-9 The Cerebrum • Alpha Waves • Found in healthy, awake adults at rest with eyes closed • Beta Waves • Higher frequency • Found in adults concentrating or mentally stressed © 2015 Pearson Education, Inc. Figure 14-18a Brain Waves. a Alpha waves are characteristic of normal resting adults 0 Seconds © 2015 Pearson Education, Inc. 1 2 3 4 Figure 14-18b Brain Waves. b Beta waves typically accompany intense concentration 0 Seconds © 2015 Pearson Education, Inc. 1 2 3 4 14-9 The Cerebrum • Theta Waves • Found in children • Found in intensely frustrated adults • May indicate brain disorder in adults • Delta Waves • During sleep • Found in awake adults with brain damage © 2015 Pearson Education, Inc. Figure 14-18c Brain Waves. c Theta waves are seen in children and in frustrated adults 0 Seconds © 2015 Pearson Education, Inc. 1 2 3 4 Figure 14-18d Brain Waves. d Delta waves occur in deep sleep and in certain pathological conditions © 2015 Pearson Education, Inc. 0 Seconds 1 2 3 4 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 • 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 • 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. 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 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) 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 Figure 14-24a 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 14-24b 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 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 VI N VII Medulla oblongata Tympanic membrane © 2015 Pearson Education, Inc. Auditory tube Cochlea Cochlear branch (N VIII) N IX N XII NX N XI 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. 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 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. 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. Table 14-4 Cranial Nerve Branches and Functions (Part 1 of 2). © 2015 Pearson Education, Inc. Table 14-4 Cranial Nerve Branches and Functions (Part 2 of 2). © 2015 Pearson Education, Inc. Table 14-5 Cranial Reflexes. © 2015 Pearson Education, Inc.
