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Chapter 9: The Nervous System: The Brain and Cranial Nerves Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Brain • Cerebrum – Cerebral hemispheres – Longitudinal fissure (fissure is a deep groove) – Lobes • Diencephalon – Thalamus – Hypothalamus • Brain stem – Midbrain – Pons – Medulla oblongata • Cerebellum means “little brain” Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Brain, sagittal section. Main divisions are shown. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body External surface of the brain, superior view. The division into two hemisphere s and into lobes is visible. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Protective Structures of the Brain and Spinal Cord • Meninges-3 layers of connective tissue surrounding the brain and spinal cord – Dura mater • Outermost layer, thickest and toughest • Dural sinuses – Arachnoid • Middle layer – Pia mater • Innermost layer • Attached to the nervous tissue of the brain and spinal cord Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Frontal (coronal) section of the top of the head. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Cerebrospinal Fluid • Clear fluid circulating in and around the brain and spinal cord • Supports nervous tissue, cushions from shock • Carries nutrients to cells • Transports waste products from cells • Produced in ventricles – Choroid plexus – Lateral ventricles – Foramina – Cerebral aqueduct Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Ventricles • Choroid plexus – Forms CSF • Interventricular foramina-lateral ventricles communicate with the third ventricle Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Flow of (CSF). Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Ventricles of the brain. Three views are shown. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Cerebral Hemispheres • Lobes • Cerebral cortex – Frontal – Gyri – Parietal – Sulci – Temporal • Central sulcus – Occipital – Insula (within the hemisphere) • Lateral sulcus • Basal nuclei (basal ganglia) • Corpus callosum • Internal capsule Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body External surface of the brain, lateral view. The lobes and surface features of the cerebrum are visible. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Functions of the Cerebral Cortex • Frontal lobe • Temporal lobe – Motor area – Auditory area – Speech centers – Olfactory area • Parietal lobe • Occipital lobe – Sensory area – Visual receiving area – Estimation of distances, sizes, shapes – Visual association area Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Functional areas of the cerebral cortex. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Motor areas of the cerebral cortex (frontal lobe). Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Communication Areas • Auditory areas – Auditory receiving – Auditory association – Speech comprehension (Wernicke area) • Motor areas – Motor speech (Broca area) – Written speech center • Visual areas – Visual language images receiving Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Memory and the Learning Process • Short-term memory – Information lost unless reinforced • Long-term memory – Rehearsal (repetition) – Alertness Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Diencephalon • Thalamus – Sorts sensory impulses – Directs impulses within cerebral cortex • Hypothalamus – Maintains homeostasis – *Controls sympathetic and parasympathetic divisions of autonomic nervous system – Influences heartbeat, blood flow, hormone secretion Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Regions of the diencephalon. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Limbic System • Between cerebrum and diencephalon • Includes the hippocampus – Located under te lateral ventricles • Involved in emotional states, behavior • Involved in learning, long-term memory • Stimulates the reticular formation – Network that extends along the brain stem and governs wakefulness and sleep • Links functions of cerebral cortex and brain stem Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Brain Stem • Connects cerebrum and diencephalon with the spinal cord • Composed of midbrain, pons, and medulla oblongata Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Midbrain • Superior part of brain stem • Four masses form superior part of midbrain – These act as centers for some reflexes involving the eye and ear • Conducts impulses between higher centers of cerebrum and lower centers of pons, medulla, cerebellum, spinal cord Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Pons • Connecting link between cerebellum and rest of nervous system (connects the midbrain and medulla) • Some reflexes involving respiration Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Medulla Oblongata • Located between the pons and spinal cord • Respiratory center • Cardiac center • Vasomotor center • Contralateral (opposite side) control Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body The Cerebellum • Three parts – Vermis – Left hemisphere – Right hemisphere • Outer area of gray matter with inner portion mainly white matter which is distributed in a treelike pattern • Functions – Help coordinate voluntary muscles – Help maintain balance – Help maintain muscle tone Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Brain Studies Imaging techniques to study the brain without surgery • Computed tomography (CT) scan • Magnetic resonance imaging (MRI) • Positron emission tomography (PET) • Electroencephalograph (EEG) Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Imaging the brain. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Electroencephalograph • Record electric currents given off by brain nerve cells • Study sleep patterns • Diagnose disease • Locate tumors • Study drug effects • Determine brain death Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Cranial Nerves • 12 pairs • Four categories – Special sensory impulses – General sensory impulses – Somatic motor impulses – Visceral motor impulses Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Names and Functions of the Cranial Nerves • I Olfactory-On • VII Facial-Finn • II Optic-Old • VIII VestibulocochlearVersus • III Oculomotor-Olympus • IV Trochlear-Towering • IX GlossopharyngealGerman • V Trigeminal-Tops • X Vagus-Viewed • VI Abducens-A • XI Accessory-All • XII Hypoglossal-Hops Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Cranial Nerves-Sensory, Motor, Mixed (both) • I-Sensory-Some • VII-Both-Brother • II-Sensory-Say • VII-Sensory-Say • III-Motor-Marry • IX-Both-Bad • IV-Motor-Money • X-Both-Business • V-Both-But • XI-Motor-Marry • VI-Motor-My • XII-Motor-Money Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Taylor: Memmler’s Structure and Function of the Human Body Aging of the Nervous System • Decreased brain size and weight • Decreased speed of information processing • Slowed movements • Diminished memory • Reduced blood flow to brain Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins