The Brain and Cranial Nerves

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1 14 The Brain and Cranial Nerves PowerPoint Lecture Presentations prepared by Jason LaPres Lone Star College North Harris

2 An Introduction to the Brain and Cranial Nerves The Adult Human Brain Average weight about 1.4 kg (3 lb)

3 14-1 The Brain Six Regions of the Brain 1. Cerebrum 2. Cerebellum 3. Diencephalon 4. Mesencephalon 5. Pons 6. Medulla oblongata

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)

5 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)

6 14-1 The Brain Cerebellum Second largest part of brain Coordinates repetitive body movements Two hemispheres Covered with cerebellar cortex

Figure 14-1 An Introduction to Brain Structures and Functions Left cerebral hemisphere Gyri CEREBRUM Conscious thought processes, intellectual functions Memory storage and processing Conscious and

7 Figure 14-1 An Introduction to Brain Structures and Functions Left cerebral hemisphere Gyri CEREBRUM Conscious thought processes, intellectual functions Memory storage and processing Conscious and subconscious regulation of skeletal muscle contractions Sulci Fissures CEREBELLUM Spinal cord Coordinates complex somatic motor patterns Adjusts output of other somatic motor centers in brain and spinal cord

8 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

9 14-1 The Brain Diencephalon Thalamus Relays and processes sensory information Hypothalamus Hormone production Emotion Autonomic function

10 14-1 The Brain Diencephalon Pituitary gland Major endocrine gland Connected to hypothalamus Interfaces nervous and endocrine systems

11 14-1 The Brain The Brain Stem Processes information between: Spinal cord and cerebrum or cerebellum Includes: Midbrain Pons Medulla oblongata

12 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

13 14-1 The Brain Medulla Oblongata Connects brain to spinal cord Relays information Regulates autonomic functions Heart rate, blood pressure, and digestion

Figure 14-1 An Introduction to Brain Structures and Functions DIENCEPHALON THALAMUS Relay and processing centers for sensory information HYPOTHALAMUS Centers controlling emotions, autonomic

14 Figure 14-1 An Introduction to Brain Structures and Functions DIENCEPHALON THALAMUS Relay and processing centers for sensory information HYPOTHALAMUS Centers controlling emotions, autonomic functions, and hormone production MIDBRAIN Processing of visual and auditory data Generation of reflexive somatic motor responses Maintenance of consciousness Brain stem 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)

15 14-1 The Brain Ventricles of the Brain Each cerebral hemisphere contains one large lateral ventricle Separated by a thin medial partition (septum pellucidum)

16 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)

17 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

18 Figure 14-2a Ventricles of the Brain Cerebral hemispheres Ventricles of the Brain Lateral ventricles Interventricular foramen Third ventricle Cerebral aqueduct Pons Medulla oblongata Spinal cord Ventricular system, lateral view Central canal Fourth ventricle

19 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 Ventricular system, anterior view

20 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

21 14-2 Brain Protection and Support Physical Protection of the Brain Bones of the cranium Cranial meninges Cerebrospinal fluid Biochemical Isolation Blood brain barrier

22 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

23 14-2 Brain Protection and Support The Cranial Meninges Dura mater Inner fibrous layer (meningeal layer) Outer fibrous layer (endosteal layer) fused to periosteum Venous sinuses between two layers

24 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

Figure 14-3a The Relationship among the Brain, Cranium, and Meninges Dura mater (endosteal layer) Dural sinus Dura mater (meningeal layer) Subdural space Arachnoid mater Subarachnoid space Arachnoid

25 Figure 14-3a The Relationship among the Brain, Cranium, and Meninges Dura mater (endosteal layer) Dural sinus Dura mater (meningeal layer) Subdural space Arachnoid mater Subarachnoid space Arachnoid trabeculae Pia mater Cerebral cortex Cranium (skull) Cerebral cortex Cerebellum Medulla oblongata Spinal cord A lateral view of the brain, showing its position in the cranium and the organization of the meninges

26 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

27 14-2 Brain Protection and Support Cerebrospinal Fluid (CSF) Choroid plexus Specialized ependymal cells and capillaries Secrete CSF into ventricles Produces about 500 ml of CSF/day

28 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

29 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

Figure 14-4a The Formation and Circulation of Cerebrospinal Fluid Extension of choroid plexus into lateral ventricle Arachnoid granulations Choroid plexus of third ventricle Cerebral

30 Figure 14-4a The Formation and Circulation of Cerebrospinal Fluid Extension of choroid plexus into lateral ventricle Arachnoid granulations Choroid plexus of third ventricle Cerebral aqueduct Superior sagittal sinus Lateral aperture Choroid plexus of fourth ventricle Median aperture Arachnoid mater Subarachnoid space Central canal Dura mater Spinal cord Filum terminale

Figure 14-4b The Formation and Circulation of Cerebrospinal Fluid Superior sagittal sinus Cranium Dura mater (endosteal layer) Arachnoid granulation Fluid movement Arachnoid

31 Figure 14-4b The Formation and Circulation of Cerebrospinal Fluid Superior sagittal sinus Cranium Dura mater (endosteal layer) Arachnoid granulation Fluid movement Arachnoid trabeculae Cerebral cortex The relationship of the arachnoid granulations and dura mater. Pia mater Subarachnoid space Dura mater (meningeal layer) Subdural space Arachnoid mater

32 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

33 Figure Arteries of the Neck and Head

34 Figure 21 24a Arteries of the Brain

35 Figure 21 24b Arteries of the Brain

36 Figure 21 29a Major Veins of the Head, Neck, and Brain

37 Figure 21 29b Major Veins of the Head, Neck, and Brain

38 Figure 21 29c Major Veins of the Head, Neck, and Brain

39 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

40 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

Figure 14-5a The Diencephalon and Brain Stem Cerebral peduncle Optic tract Cranial nerves N II N III N IV N V Thalamus Diencephalon Lateral geniculate nucleus Medial geniculate nucleus Midbrain

41 Figure 14-5a The Diencephalon and Brain Stem Cerebral peduncle Optic tract Cranial nerves N II N III N IV N V Thalamus Diencephalon Lateral geniculate nucleus Medial geniculate nucleus Midbrain Superior colliculus Inferior colliculus Cerebellar peduncles Superior cerebellar peduncle N VI N VII N VIII N IX N X N XI N XII Pons Spinal nerve C 1 Spinal nerve C 2 Medulla oblongata Spinal cord Middle cerebellar peduncle Inferior cerebellar peduncle Lateral view

42 Figure 14-5b The Diencephalon and Brain Stem Infundibulum Optic chiasm Cranial nerves Thalamus N II N III N IV N V N VI N VII N VIII N IX N X N XI N XII Pons Optic tract Cerebral peduncle Mamillary body Medulla oblongata Ventral roots of spinal nerves C 1 and C 2 Anterior view Spinal cord

Figure 14-5c The Diencephalon and Brain Stem Choroid plexus Thalamus Third ventricle Pineal gland Corpora quadrigemina Superior colliculi N IV Inferior colliculi

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

44 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

45 14-3 The Medulla Oblongata Autonomic Nuclei of the Medulla Oblongata Reticular formation Gray matter with embedded nuclei Regulates autonomic functions

46 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

47 14-3 The Medulla Oblongata Sensory and Motor Nuclei of the Medulla Oblongata Associated with 5 of 12 cranial nerves (VIII, IX, X, XI, XII)

48 14-4 The Pons The Pons 1. Sensory and motor nuclei of cranial nerves (V, VI, VII, VIII) 2. Nuclei involved with respiration Apneustic center and pneumotaxic center Modify respiratory rhythmicity center activity 3. Nucei that process and relay information to and from cerebellum

Figure 14-6c The Medulla Oblongata and Pons Tracts Ascending tracts Descending tracts Respiratory Centers Pneumotaxic center Apneustic center

49 Figure 14-6c The Medulla Oblongata and Pons Tracts Ascending tracts Descending tracts Respiratory Centers Pneumotaxic center Apneustic center Midbrain Transverse fibers Cerebellum Fourth ventricle Pons Medulla oblongata Medulla oblongata Olivary nucleus Reticular formation Spinal cord Lateral view

50 14-5 The Cerebellum Functions of the Cerebellum 1. Adjusts postural muscles 2. Fine-tunes conscious and subconscious movements

51 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

52 Figure 14-7a The Cerebellum Vermis Anterior lobe Primary fissure Posterior lobe Folia Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum The posterior, superior surface of the cerebellum, showing major anatomical landmarks and regions

53 Figure 14-7a The Cerebellum Vermis Anterior lobe Folia Primary fissure Posterior lobe Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum The posterior, superior surface of the cerebellum, showing major anatomical landmarks and regions

Figure 14-7b The Cerebellum Midbrain Anterior lobe Cerebellar Peduncles Superior cerebellar peduncle Pons Arbor vitae Cerebellar nucleus Middle cerebellar peduncle Inferior cerebellar peduncle

54 Figure 14-7b The Cerebellum Midbrain Anterior lobe Cerebellar Peduncles Superior cerebellar peduncle Pons Arbor vitae Cerebellar nucleus Middle cerebellar peduncle Inferior cerebellar peduncle Medulla oblongata Choroid plexus of the fourth ventricle Cerebellar cortex Posterior lobe Flocculonodular lobe A sectional view of the cerebellum, showing the arrangement of gray matter and white matter

55 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)

56 Figure 14-8a The Midbrain Thalamus Pineal gland Red nucleus Substantia nigra Corpora quadrigemina Cerebral peduncle Superior colliculus Inferior colliculus A posterior view. The underlying nuclei are colored only on the right. Reticular formation

57 Figure 14-8b The Midbrain Cerebral peduncle Substantia nigra ANTERIOR Cerebellum Red nucleus Cerebral aqueduct Superior colliculus Tectum Tegmentum POSTERIOR A superior view of a transverse section at the level of the midbrain.

58 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

59 14-7 The Diencephalon The Thalamus Filters ascending sensory information for primary sensory cortex Relays information between basal nuclei and cerebral cortex

60 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

61 Figure 14-9a The Thalamus Frontal lobe Parietal lobe Occipital lobe A lateral view of the brain, color coded to indicate the regions that receive input from the thalamic nuclei shown in part (b)

Figure 14-10a The Hypothalamus in Sagittal Section Autonomic centers (sympathetic) Paraventricular nucleus Thalamus Interthalamic adhesion Preoptic area Autonomic centers (parasympathetic)

62 Figure 14-10a The Hypothalamus in Sagittal Section Autonomic centers (sympathetic) Paraventricular nucleus Thalamus Interthalamic adhesion Preoptic area Autonomic centers (parasympathetic) Hypothalamus Suprachiasmatic nucleus Supraoptic nucleus Tuberal nuclei Optic chiasm Infundibulum Tuberal area Mamillary body Midbrain Pituitary gland Pons A diagrammatic view of the hypothalamus, showing the locations of major nuclei and centers

63 Figure 14-10b The Hypothalamus in Sagittal Section Parietal lobe Choroid plexus Thalamus (surrounds third ventricle) Pineal gland Hypothalamus Aqueduct of midbrain Cerebellum Fourth ventricle Mamillary body The hypothalamus and adjacent portions of the brain

64 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

65 14-7 The Diencephalon Eight Functions of the Hypothalamus 5. Produces emotions and behavioral drives The feeding center (hunger) The thirst center (thirst) 6. Coordinates voluntary and autonomic functions 7. Regulates body temperature 8. Controls circadian rhythms (day night cycles)

66 14-8 The Limbic System The Limbic System Is a functional grouping that: Establishes emotional states Links conscious functions of cerebral cortex with autonomic functions of brain stem Facilitates memory storage and retrieval

67 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

68 14-8 The Limbic System Components of the Limbic System Fornix Tract of white matter Connects hippocampus with hypothalamus Anterior nucleus of the thalamus Relays information from mamillary body to cingulate gyrus Reticular formation Stimulation or inhibition affects emotions (rage, fear, pain, sexual arousal, pleasure)

Figure 14-11a The Limbic System Corpus callosum Fornix Pineal gland Components of the Limbic System in the Cerebrum The region of the cerebral hemisphere shown in green is known as the limbic lobe.

69 Figure 14-11a The Limbic System Corpus callosum Fornix Pineal gland Components of the Limbic System in the Cerebrum The region of the cerebral hemisphere shown in green is known as the limbic lobe. Components of the Limbic System in the Diencephalon Anterior group of thalamic nuclei Cingulate gyrus (superior portion of limbic lobe) Parahippocampal gyrus (inferior portion of limbic lobe) Hippocampus Hypothalamus Mamillary body Temporal lobe of cerebrum 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.

Figure 14-11b The Limbic System Cingulate gyrus Corpus callosum Anterior nucleus of thalamus Fornix Hypothalamic nuclei Mamillary body Olfactory tract Amygdaloid body

70 Figure 14-11b The Limbic System Cingulate gyrus Corpus callosum Anterior nucleus of thalamus Fornix Hypothalamic nuclei Mamillary body Olfactory tract Amygdaloid body Hypothalamus Parahippocampal gyrus Hippocampus (with dentate gyrus) A three-dimensional reconstruction of the limbic system, showing the relationships among the major components.

71 Table 14-7 The Limbic System

72 14-9 The Cerebrum The Cerebrum Is the largest part of the brain Controls all conscious thoughts and intellectual functions Processes somatic sensory and motor information

73 14-9 The Cerebrum Gray Matter In cerebral cortex and basal nuclei White Matter Deep to basal cortex Around basal nuclei

74 14-9 The Cerebrum Structures of the Cerebrum Gyri of neural cortex Increase surface area (number of cortical neurons) Longitudinal fissure Separates cerebral hemispheres Lobes Divisions of hemispheres

75 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

76 Figure 14-12a The Brain in Lateral View Central sulcus FRONTAL LOBE PARIETAL LOBE Lateral sulcus TEMPORAL LOBE Pons OCCIPITAL LOBE Cerebellum Medulla oblongata Lateral view, cadaver brain

77 Figure 14-12b The Brain in Lateral View Precentral gyrus Central sulcus Postcentral gyrus FRONTAL LOBE PARIETAL LOBE OCCIPITAL LOBE Lateral sulcus TEMPORAL LOBE Cerebellum Lateral view Pons Medulla oblongata

78 Figure 14-12d The Brain in Lateral View Precentral gyrus Cingulate gyrus Central sulcus Postcentral gyrus PARIETAL LOBE FRONTAL LOBE Parietooccipital sulcus OCCIPITAL LOBE TEMPORAL LOBE Pons Cerebellum Medulla oblongata Midsagittal section

79 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

80 14-9 The Cerebrum The Basal Nuclei Are masses of gray matter Are embedded in white matter of cerebrum Direct subconscious activities

81 14-9 The Cerebrum Anatomy of Basal Nuclei Caudate nucleus Curving, slender tail Lentiform nucleus Globus pallidus Putamen

82 Figure 14-14a The Basal Nuclei Head of caudate nucleus Lentiform nucleus Amygdaloid body The relative positions of the basal nuclei in the intact brain, lateral view Tail of caudate nucleus Thalamus

Figure 14-14b The Basal Nuclei Head of caudate nucleus Internal capsule Putamen Thalamus Choroid plexus Pineal gland Corpus callosum Lateral ventricle

83 Figure 14-14b The Basal Nuclei Head of caudate nucleus Internal capsule Putamen Thalamus Choroid plexus Pineal gland Corpus callosum Lateral ventricle (anterior horn) Septum pellucidum Fornix (cut edge) Third ventricle Fornix Lateral ventricle (posterior horn) A horizontal section as seen in a dissection

84 Figure 14-14c The Basal Nuclei Lateral ventricle Head of caudate nucleus Lentiform nucleus Claustrum Insula Putamen Globus pallidus Amygdaloid body Frontal section Corpus callosum Septum pellucidum Internal capsule Lateral sulcus Anterior commissure Tip of lateral ventricle

85 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)

86 14-9 The Cerebrum Motor and Sensory Areas of the Cortex Central sulcus separates motor and sensory areas Motor areas

87 14-9 The Cerebrum Motor and Sensory Areas of the Cortex Sensory areas Primary sensory cortex Surface of postcentral gyrus

88 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

Figure 14-15a Motor and Sensory Regions of the Cerebral Cortex Primary motor cortex (precentral gyrus) Central sulcus Primary sensory cortex (postcentral gyrus) Somatic motor association area

89 Figure 14-15a Motor and Sensory Regions of the Cerebral Cortex Primary motor cortex (precentral gyrus) Central sulcus Primary sensory cortex (postcentral gyrus) Somatic motor association area (premotor cortex) FRONTAL LOBE Prefrontal cortex Gustatory cortex Insula Lateral sulcus Olfactory cortex TEMPORAL LOBE PARIETAL LOBE Somatic sensory association area Visual association area OCCIPITAL LOBE Visual cortex Auditory association area Auditory cortex Major anatomical landmarks on the surface of the left cerebral hemisphere. The lateral sulcus has been pulled apart to expose the insula.

90 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)

91 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)

92 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

93 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

94 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)

Figure 14-15b Motor and Sensory Regions of the Cerebral Cortex Frontal eye field Speech center Prefrontal cortex General interpretive area The left hemisphere

95 Figure 14-15b Motor and Sensory Regions of the Cerebral Cortex Frontal eye field Speech center Prefrontal cortex General interpretive area 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.

96 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

97 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)

Figure 14-16 Hemispheric Lateralization Left Cerebral Hemisphere LEFT HAND Prefrontal cortex Speech center Writing Auditory cortex

98 Figure Hemispheric Lateralization Left Cerebral Hemisphere LEFT HAND Prefrontal cortex Speech center Writing Auditory cortex General interpretive center (language and mathematical calculation) C O R P U S C A L L O S U M Visual cortex (right visual field)

Figure 14-16 Hemispheric Lateralization Right Cerebral Hemisphere RIGHT HAND Prefrontal cortex C O R P U S C A L L O S U M

99 Figure Hemispheric Lateralization Right Cerebral Hemisphere RIGHT HAND Prefrontal cortex C O R P U S C A L L O S U M Anterior commissure Analysis by touch Auditory cortex Spatial visualization and analysis Visual cortex (left visual field)

100 14-10 Cranial Nerves Cranial Nerves 12 pairs connected to brain Four Classifications of Cranial Nerves 1. Sensory nerves carry somatic sensory information, including touch, pressure, vibration, temperature, and pain 2. Special sensory nerves carry sensations such as smell, sight, hearing, balance 3. Motor nerves: axons of somatic motor neurons 4. Mixed nerves: mixture of motor and sensory fibers

Figure 14-18 Origins of the Cranial Nerves Olfactory bulb: termination of olfactory nerve (I) Olfactory tract Optic

101 Figure Origins of the Cranial Nerves Olfactory bulb: termination of olfactory nerve (I) Olfactory tract Optic nerve (II) Infundibulum Oculomotor nerve (III) Pons Basilar artery Vertebral artery Cerebellum Medulla oblongata Spinal cord

Figure 14-18 Origins of the Cranial Nerves Optic chiasm Optic tract Mamillary body Trochlear nerve (IV) Trigeminal nerve (V) Abducens nerve

102 Figure Origins of the Cranial Nerves Optic chiasm Optic tract Mamillary body Trochlear nerve (IV) Trigeminal nerve (V) Abducens nerve (VI) Facial nerve (VII) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Vagus nerve (X) Hypoglossal nerve (XII) Accessory nerve (XI)

103 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

Figure 14-19 The Olfactory Nerve Olfactory tract (to olfactory cortex of cerebrum) Left olfactory bulb

104 Figure The Olfactory Nerve Olfactory tract (to olfactory cortex of cerebrum) Left olfactory bulb (termination of olfactory nerve) OLFACTORY NERVE (N I) Olfactory nerve fibers Cribriform plate of ethmoid Olfactory epithelium

105 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

106 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

Figure 14-20 The Optic Nerve Pituitary gland Eye Olfactory bulb Olfactory tract OPTIC NERVE (N II) Optic chiasm Optic

107 Figure The Optic Nerve Pituitary gland Eye Olfactory bulb Olfactory tract OPTIC NERVE (N II) Optic chiasm Optic tract Lateral geniculate nucleus (in thalamus) Midbrain (cut) Visual cortex (in occipital lobes) Optic projection fibers

108 14-10 Cranial Nerves Oculomotor Nerves (III) Primary function: Motor (eye movements) Origin: Midbrain Pathway: Superior orbital fissures of sphenoid

109 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

Figure 14-21 Cranial Nerves Controlling the Extra-Ocular Muscles Superior oblique muscle Superior rectus muscle OPTIC NERVE (N II) Optic chiasm OCULOMOTOR NERVE (N III) TROCHLEAR NERVE (N IV)

110 Figure Cranial Nerves Controlling the Extra-Ocular 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 muscle Ciliary ganglion Medial rectus muscle Lateral rectus muscle (cut) ABDUCENS NERVE (N VI) Facial nerve (N VII), cut

111 14-10 Cranial Nerves The Trigeminal Nerves (V) Primary function: Mixed (sensory and motor) to face Origin: Ophthalmic branch (sensory) Orbital structures Nasal cavity Skin of forehead, upper eyelid, and eyebrow Part of nose

112 14-10 Cranial Nerves The Trigeminal Nerves (V) Origin: Maxillary branch (sensory) Lower eyelid Upper lip, gums, and teeth Cheek and nose Palate and part of pharynx

113 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

114 14-10 Cranial Nerves The Trigeminal Nerves (V) Pathway: Ophthalmic branch Superior orbital fissure Maxillary branch Foramen rotundum Mandibular branch Foramen ovale

115 14-10 Cranial Nerves The Trigeminal Nerves (V) Destination: Sensory nerves Sensory nuclei in pons Motor nerves of mandibular branch Muscles of mastication

116 Figure The Trigeminal Nerve Superior orbital fissure Supra-orbital nerves Ciliary ganglion Foramen rotundum Infra-orbital nerve Lingual nerve Submandibular ganglion Pons Ophthalmic branch Semilunar ganglion TRIGEMINAL NERVE (N V) Maxillary branch Foramen ovale Otic ganglion Mandibular branch Mental nerve Pterygopalatine ganglion

117 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 Pathway: Motor nuclei of pons Internal acoustic meatus to facial canals (stylomastoid foramina)

118 14-10 Cranial Nerves The Facial Nerves (VII) Destination: Sensory Sensory nuclei of pons Somatic motor Muscles of facial expression Visceral motor Tear and nasal mucous glands Submandibular and sublingual salivary glands

119 14-10 Cranial Nerves Facial Nerve Structures Facial nerve branches Temporal Zygomatic Buccal Mandibular Cervical branches

Figure 14-23a The Facial Nerve Pterygopalatine ganglion Greater petrosal nerve Geniculate ganglion FACIAL NERVE (N VII) Temporal branch Pons Zygomatic branches Buccal branch Mandibular branch

120 Figure 14-23a The Facial Nerve Pterygopalatine ganglion Greater petrosal nerve Geniculate ganglion FACIAL NERVE (N VII) Temporal branch Pons Zygomatic branches Buccal branch Mandibular branch Cervical branch Posterior auricular branch Stylomastoid foramen Chorda tympani nerve (with mandibular branch of N V) Lingual branch (with lingual nerve of N V) The origin and branches of the facial nerve Submandibular ganglion

121 Figure 14-23b The Facial Nerve Temporal branch Zygomatic branch Buccal branch Mandibular branch Cervical branch The superficial distribution of the five major branches of the facial nerve

122 14-10 Cranial Nerves The Vestibulocochlear Nerves (VIII) Primary function: Special sensory Vestibular branch Balance and equilibrium Cochlear branch Hearing

123 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

124 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

Figure 14-24 The Vestibulocochlear Nerve Tympanic cavity (middle ear) Semicircular canals Vestibular branch (N VIII) Facial nerve (N VII), cut Internal acoustic

125 Figure The Vestibulocochlear Nerve Tympanic cavity (middle ear) Semicircular canals Vestibular branch (N VIII) Facial nerve (N VII), cut Internal acoustic meatus VESTIBULOCOCHLEAR NERVE (N VIII) N V Pons N VI N VII Medulla oblongata N IX N XII N X N XI Tympanic membrane Auditory tube Cochlea Cochlear branch (N VIII)

126 14-10 Cranial Nerves The Glossopharyngeal Nerves (IX) Primary function: Mixed (sensory and motor) to head and neck

127 14-10 Cranial Nerves The Glossopharyngeal Nerves (IX) Origins: Sensory Posterior 1/3 of tongue Part of pharynx and palate Carotid arteries Motor Motor nuclei of medulla oblongata

Figure 14-25 The Glossopharyngeal Nerve Otic ganglion Inferior (petrosal) ganglion Lingual branch N VII N VI Pons N V N VIII GLOSSOPHARYNGEAL NERVE (N IX)

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

129 14-10 Cranial Nerves The Vagus Nerves (X) Primary function: Mixed (sensory and motor) Widely distributed in thorax and abdomen

130 14-10 Cranial Nerves The Vagus Nerves (X) Origins: Sensory Part of pharynx Auricle and external acoustic meatus Diaphragm Visceral organs of thoracic and abdominopelvic cavities Motor Motor nuclei in medulla oblongata

131 14-10 Cranial Nerves The Vagus Nerves (X) Pathway: Jugular foramina Between occipital and temporal bones

132 14-10 Cranial Nerves The Vagus Nerves (X) Destination: Sensory Sensory nuclei and autonomic centers of medulla oblongata Visceral motor Muscles of the palate and pharynx Muscles of the digestive, respiratory, and cardiovascular systems in thoracic and abdominal cavities

133 14-10 Cranial Nerves Vagus Nerve Structures Vagus nerves Branch and radiate extensively Superior (jugular) ganglion and inferior (nodose) ganglion Hold sensory neurons

Figure 14-26 The Vagus Nerve Superior pharyngeal branch VAGUS NERVE (N X) Pons Medulla oblongata Auricular branch to external ear Superior

134 Figure The Vagus Nerve Superior pharyngeal branch VAGUS NERVE (N X) Pons Medulla oblongata Auricular branch to external ear Superior laryngeal nerve Internal branch External branch Inferior ganglion of vagus nerve Superior ganglion of vagus nerve Pharyngeal branch Superior laryngeal nerve

Figure 14-26 The Vagus Nerve Recurrent laryngeal nerve Cardiac branches Cardiac plexus Right lung Left

135 Figure The Vagus Nerve 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

136 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

137 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

138 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

Figure 14-27 The Accessory and Hypoglossal Nerves HYPOGLOSSAL NERVE (N XII) ACCESSORY NERVE (N XI) Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve Trigeminal nerve (N

139 Figure 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 Intrinsic muscles of tongue Styloglossus muscle Genioglossus muscle Spinal root of N XI External branch of N XI Geniohyoid muscle Hyoglossus muscle Hyoid bone Spinal cord Trapezius muscle Thyrohyoid muscle Sternohyoid muscle Sternothyroid muscle Sternocleidomastoid muscle Ansa cervicalis (cervical plexus) Omohyoid muscle

140 14-10 Cranial Reflexes Cranial Reflexes Monosynaptic and polysynaptic reflex arcs Involve sensory and motor fibers of cranial nerves Clinically useful to check cranial nerve for brain damage

141 Table Cranial Reflexes

C h a p t e r PowerPoint Lecture Slides prepared by Jason LaPres North Harris College Houston, Texas

C h a p t e r PowerPoint Lecture Slides prepared by Jason LaPres North Harris College Houston, Texas C h a p t e r 15 The Nervous System: The Brain and Cranial Nerves PowerPoint Lecture Slides prepared by Jason LaPres North Harris College Houston, Texas Copyright 2009 Pearson Education, Inc., publishing