14 The Brain and Cranial Nerves C h a p t e r PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Cerebellum Second largest part of brain Coordinates repetitive body movements Two hemispheres Covered with cerebellar cortex Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain Diencephalon Thalamus Hypothalamus Pituitary gland Relays and processes sensory information Hypothalamus Hormone production Emotion Autonomic function Pituitary gland Major endocrine gland Connected to hypothalamus Via infundibulum (stalk) Interfaces nervous and endocrine systems Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain The Brain Stem Processes information between Includes Spinal cord and cerebrum or cerebellum Includes Mesencephalon Pons Medulla oblongata Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain The Brain Stem Mesencephalon Pons Also called midbrain Processes sight, sound, and associated reflexes Maintains consciousness Pons Connects cerebellum to brain stem Is involved in somatic and visceral motor control Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Brain The Brain Stem Medulla oblongata Connects brain to spinal cord Relays information Regulates autonomic functions: heart rate, blood pressure, and digestion Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–5a The Diencephalon and Brain Stem. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–5b The Diencephalon and Brain Stem. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–5c The Diencephalon and Brain Stem. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Autonomic Nuclei of the Medulla Oblongata Reticular formation Gray matter with embedded nuclei Regulates autonomic functions Reflex centers Control peripheral systems: cardiovascular centers: cardiac center control blood flow through peripheral tissues respiratory rhythmicity centers sets pace for respiratory movements Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Sensory and Motor Nuclei of the Medulla Oblongata Associated with 5 of 12 cranial nerves (VIII, IX, X, XI, XII) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–6a The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Medulla Oblongata Figure 14–6b The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons The Pons Links cerebellum with mesencephalon, diencephalon, cerebrum, and spinal cord Sensory and motor nuclei of cranial nerves V, VI, VII, VIII Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons The Pons Nuclei involved with respiration Nuclei and tracts Apneustic center and pneumotaxic center: modify respiratory rhythmicity center activity Nuclei and tracts Process and relay information to and from cerebellum Ascending, descending, and transverse tracts: transverse fibers (axons): link nuclei of pons with opposite cerebellar hemisphere Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Figure 14–6a The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Figure 14–6b The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Figure 14–6c The Medulla Oblongata and Pons. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Pons Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Functions of the Cerebellum Adjusts postural muscles Fine-tunes conscious and subconscious movements Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Vermis Narrow band of cortex Flocculonodular lobe Below fourth ventricle Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Structures of the Cerebellum Purkinje cells Arbor vitae Large, branched cells Found in cerebellar cortex Receive input from up to 200,000 synapses Arbor vitae Highly branched, internal white matter of cerebellum Cerebellar nuclei: embedded in arbor vitae: relay information to Purkinje cells Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Disorders of the Cerebellum Ataxia Damage from trauma or stroke Intoxication (temporary impairment) Disturbs muscle coordination Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Figure 14–7a The Cerebellum. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Figure 14–7b The Cerebellum. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebellum Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Structures of the Mesencephalon Tectum Two pairs of sensory nuclei (corpora quadrigemina): superior colliculus (visual) inferior colliculus (auditory) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Structures of the Mesencephalon Cerebral peduncles Nerve fiber bundles on ventrolateral surfaces Contain: descending fibers to cerebellum motor command fibers Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Figure 14–8a The Mesencephalon. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Figure 14–8b The Mesencephalon. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Mesencephalon Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Integrates sensory information and motor commands Thalamus, epithalamus, and hypothalamus The pineal gland Found in posterior epithalamus Secretes hormone melatonin Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon The Thalamus Filters ascending sensory information for primary sensory cortex Relays information between basal nuclei and cerebral cortex The third ventricle Separates left thalamus and right thalamus Interthalamic adhesion (or intermediate mass): projection of gray matter extends into ventricle from each side Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–9 The Thalamus. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–9a The Thalamus. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–10a The Hypothalamus in Sagittal Section. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Figure 14–10b The Hypothalamus in Sagittal Section. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Eight Functions of the Hypothalamus Provides subconscious control of skeletal muscle Controls autonomic function Coordinates activities of nervous and endocrine systems Secretes hormones Antidiuretic hormone (ADH) by supraoptic nucleus Oxytocin (OT; OXT) by paraventricular nucleus Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Eight Functions of the Hypothalamus Produces emotions and behavioral drives The feeding center (hunger) The thirst center (thirst) Coordinates voluntary and autonomic functions Regulates body temperature Preoptic area of hypothalamus Controls circadian rhythms (day–night cycles) Suprachiasmatic nucleus Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Diencephalon Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum The Cerebrum Is the largest part of the brain Controls all conscious thoughts and intellectual functions Processes somatic sensory and motor information Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–12a The Brain in Lateral View. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–12b The Brain in Lateral View. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–12c The Brain in Lateral View. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Three Functional Principles of the Cerebrum Each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of the body The two hemispheres have different functions, although their structures are alike Correspondence between a specific function and a specific region of cerebral cortex is not precise Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Special Sensory Cortexes Visual cortex Auditory cortex Information from sight receptors Auditory cortex Information from sound receptors Olfactory cortex Information from odor receptors Gustatory cortex Information from taste receptors Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–15a Motor and Sensory Regions of the Cerebral Cortex. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Association Areas Sensory association areas Monitor and interpret arriving information at sensory areas of cortex Somatic motor association area (premotor cortex) Coordinates motor responses (learned movements) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Sensory Association Areas Somatic sensory association area Interprets input to primary sensory cortex (e.g., recognizes and responds to touch) Visual association area Interprets activity in visual cortex Auditory association area Monitors auditory cortex Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum General Interpretive Area Also called Wernicke area Present in only one hemisphere Receives information from all sensory association areas Coordinates access to complex visual and auditory memories Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–15b Motor and Sensory Regions of the Cerebral Cortex. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Interpretive Areas of Cortex Brodmann areas Patterns of cellular organization in cerebral cortex Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–15c Motor and Sensory Regions of the Cerebral Cortex. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum The Left Hemisphere The Right 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) Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cerebrum Figure 14–16 Hemispheric Lateralization. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings