Physiology of Behavior Twelfth Edition Chapter 3 Structure of the Nervous System Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-2 Chapter Preview • Basic Features of the Nervous System • Development of the Nervous System • The Central Nervous System • The Peripheral Nervous System Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Learning Objectives (1 of 3) 3.1 Apply anatomical terms to the nervous system. 3.2 Differentiate the locations of the three layers of the meninges. 3.3 Describe the locations and functions of CSF within the ventricular system. 3.4 Summarize the process of human brain development from ectoderm plate, to neural tube, to three interconnected chambers. 3.5 Explain how prenatal development contributes to the development of complex human brains. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Learning Objectives (2 of 3) 3.6 Provide examples of how genetic change, personal experience, and neurogenesis can influence postnatal brain development. 3.7 Identify the structures and functions of the forebrain, including the telencephalon and diencephalon. 3.8 Identify the location and functions of the structures of the mesencephalon. 3.9 Contrast the locations and functions of the structures of the metencephalon and myelencephalon. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Learning Objectives (3 of 3) 3.10 Describe the structure and functions of the spinal cord. 3.11 Identify the functions of the cranial nerves. 3.12 Differentiate between the functions of afferent and efferent axons of the spinal nerves. 3.13 Compare the functions and locations of the sympathetic and parasympathetic divisions of the autonomic nervous system. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Basic Features of the Nervous System (1 of 2) • An Overview: Directions in the Nervous System – Anterior/Rostral = Front – Posterior/Caudal = Back – Dorsal = Top – Ventral = Bottom – Lateral = Toward the Side – Medial = Toward the Middle – Ipsilateral = Same Side – Contralateral = Opposite Side Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-3 Basic Features of the Nervous System (2 of 2) • Brain Slices and Planes – – – – Cross Section or Frontal Section Horizontal Section Sagittal Section Midsagittal Plane Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-4 Basic Features of the Nervous System (3 of 3) • Central Nervous System – Brain and spinal cord (CNS) – Encased by bone – Cerebrospinal fluid • Peripheral Nervous System – – – – Cranial nerves Spinal nerves Peripheral ganglia Encased by vertebral column Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-5 Figure 3.1 The Nervous System The figures show the relation of the nervous system to the rest of the body. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-6 Figure 3.2 Anatomical Directions and Planes (1 of 2) The figures show (a) planes of section as they pertain to the nervous system illustrating the anatomical terms described in this section. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-7 Figure 3.2 Anatomical Directions and Planes (2 of 2) The figures show (b) side and frontal views illustrating the anatomical terms described in this section. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-8 Basic Features of the Nervous System Meninges 3-9 • Meninges – The protective sheath around brain and spinal cord • Dura Mater – Tough, flexible outermost meninx • Arachnoid Membrane – Middle layer of the meninges • Pia Mater – Last layer of the meninges, which adheres to the surface of the brain Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. The Ventricular System and CSF (1 of 3) • Cerebrospinal Fluid (CSF) – Clear fluid, similar to blood plasma; fills ventricular system of brain and subarachnoid space surrounding brain and spinal cord • Subarachnoid Space – Space between arachnoid membrane and pia mater filled with CSF Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-10 The Ventricular System and CSF (2 of 3) • Ventricular System and Production of CSF – Ventricles: Set of holes within brain filled with CSF • These include: – – – – Lateral Ventricles Third Ventricles Cerebral Aqueduct Fourth Ventricle Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-11 The Ventricular System and CSF (3 of 3) • Obstructive Hydrocephalus – Flow of CSF blocked – Surgical repair with valve Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-12 Figure 3.4 The Ventricular System of the Brain 3-13 The figure shows (a) a lateral view of the left side of the brain, (b) a frontal view, (c) a dorsal view, and (d) the production, circulation, and reabsorption of cerebrospinal fluid. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.5 Hydrocephalus in an Infant 3-14 A surgeon places a shunt tube in a lateral ventricle, which permits cerebrospinal fluid to escape to the abdominal cavity, where it is absorbed into the blood supply. A pressure valve regulates the flow of CSF through the shunt. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Development of Central Nervous System • Central Nervous System – Begins early in embryonic life as a hollow tube – Maintains this basic shape even after it is fully developed • Tube – Elongates – Forms pockets and folds – Thickens until the brain reaches its final form Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-15 Figure 3.6 Neural Plate Development 3-16 The figure shows development of the neural plate into the neural tube, which gives rise to the brain and spinal cord. Left: Dorsal views. Right: Cross section at levels indicated by dashed lines. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.7 Brain Development This schematic outline of brain development shows its relation to the ventricles. Views (a) and (c) show early development. Views (b) and (d) show later development. View (e) shows a lateral view of the left side of a semitransparent human brain with the brain stem “ghosted in.” The colors of all figures denote corresponding regions. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-17 Table 3.1 Anatomical Subdivisions of the Brain Major Division 3-18 Ventricle Subdivision Principal Structure Lateral Telencephalon Third Diencephalon Cerebral cortex Basal ganglia Limbic System Thalamus Hypothalamus Midbrain Cerebral aqueduct Mesencephalon Tectum Tegmentum Hindbrain Fourth Metencephalon Cerebellum Pons Medulla oblongata Forebrain Myelencephalon Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.8 Cortical Development 3-19 This cross section through the cerebral cortex shows it early in its development. The radially oriented fibers of glial cells help to guide the migration of newly formed neurons from the ventricular zone to their final resting place in the cerebral cortex. Each successive wave of neurons passes neurons that migrated earlier, so the most recently formed neurons occupy layers closer to the cortical surface. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-20 Prenatal Brain Development (1 of 2) • Cerebral cortex: surrounds hemispheres • Progenitor cells: stem cells that give rise to CNS • Development from inside out • Ventricular zone (VZ) • Symmetrical Division • Asymmetrical Division Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-21 Prenatal Brain Development (2 of 2) • The development of complex brains – Genetic duplication – More symmetrical divisions – Longer period of asymmetrical division • Overproduction and refinement • Pattern of development – Genetics – Personal experience – Neurogenesis Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.9 Refining Neural Connections: Overproduction and Refinement 3-22 Experience shapes brain architecture by early overproduction of neurons, followed by later apoptosis and refinement of synaptic connections based on learning and exposure to stimuli. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.10 Pre and Postnatal Brain Development Brain development begins during the prenatal period and extends through adulthood. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-23 Structure and Function of the CNS (1 of 2) • Forebrain: – Largest section of the brain, comprised of telencephalon and diencephalon – Cerebral Hemisphere – Sulcus – Gyrus • The Spinal Cord – Spinal roots: Cauda Equina (ee kwye na) Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-24 Structure and Function of the CNS (2 of 2) • Cerebral Cortex – – – – Primary Primary Primary Primary Visual Cortex Auditory Cortex Somatosensory Cortex Motor Cortex Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-25 Figure 3.12 Forebrain The forebrain is the most dorsal division of the brain. The forebrain consists of the telencephalon and the diencephalon. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-26 Figure 3.13 Cross Section of Human Brain This brain slice shows fissures and gyri and the layer of cerebral cortex that follows these convolutions. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-27 Figure 3.14 The Four Lobes of the Cerebral Cortex (1 of 3) 3-28 The two symmetrical hemispheres of the cortex are divided into four lobes. This figure shows the location of the four lobes, the primary sensory and motor cortex, and the association cortex. (a) Ventral view, from the base of the brain. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.14 The Four Lobes of the Cerebral Cortex (2 of 3) 3-29 This figure shows the location of the four lobes, the primary sensory and motor cortex, and the association cortex (b) Midsagittal view, with the cerebellum and brain stem removed. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.14 The Four Lobes of the Cerebral Cortex (3 of 3) 3-30 The two symmetrical hemispheres of the cortex are divided into four lobes. This figure shows the location of the four lobes, the primary sensory and motor cortex, and the association cortex. (c) Lateral view. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.15 The Primary Sensory Regions of the Brain The inset shows a cutaway of part of the frontal lobe of the left hemisphere, permitting us to see the primary auditory cortex on the dorsal surface of the temporal lobe, which forms the ventral bank of the lateral fissure. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-31 3-32 Cerebral Cortex (1 of 2) • Frontal Lobe • Parietal Lobe (pa rye i tul) • Temporal Lobe (tem por ul) • Occipital Lobe (ok sip i tul) Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-33 Cerebral Cortex (2 of 2) • Motor Association Cortex • Prefrontal Cortex • Corpus Callosum (ka loh sum) Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-34 Figure 3.16 Role of Cortical Regions in Motor Control The motor, premotor, and prefrontal cortex all contribute to motor control in the cortex. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.17 Bundles of Axons in the Corpus Callosum 3-35 This figure, obtained by means of diffusion tensor imaging, shows bundles of axons in the corpus callosum that serve different regions of the cerebral cortex. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-36 Figure 3.18 The Midsagittal View of the Brain and Part of the Spinal Cord Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-37 Limbic System • Group of brain regions including: Cingulate gyrus • Limbic cortex • Hippocampus • Amygdala • Fornix • Mammillary bodies Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.19 The Major Components of the Limbic System All of the left hemisphere except for the limbic system has been removed. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-38 3-39 The Basal Ganglia and Diencephalon • Basal Ganglia: Set of structures involved in processing information for motor movement – Includes caudate nucleus, putamen, globus pallidus • Diencephalon: Major component of the forebrain consisting largely of the thalamus and hypothalamus, Thalamus, and Hypothalamus Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.20 The Basal Ganglia and Diencephalon The basal ganglia and diencephalon (thalamus and hypothalamus) are ghosted in a semitransparent brain. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-40 3-41 Hypothalamus • Small but important structure • Organizes behaviors related to survival • Four F’s Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.21 A Midsagittal View of Part of the Brain This view shows the hypothalamus. It is situated on the far side of the wall of the third ventricle, inside the right hemisphere. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-42 3-43 Midbrain • Known as mesencephalon • comprised of: – tectum – tegmentum Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-44 Tectum • Superior Colliculi (ka lik yew lee) • Inferior Colliculi • Tegmentum Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-45 Tegmentum • Reticular Formation • Periaqueductal Gray matter • Red nucleus • Substantia Nigra Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-46 Hindbrain • Cerebellum (sair a bell um) • Pons • Medulla oblongata Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-47 Figure 3.24 The Cerebellum and the Brain Stem This figure shows (a) a lateral view of a semitransparent brain, showing the cerebellum and brain stem ghosted in, (b) a view from the back of the brain, and (c) a dorsal view of the brain stem. The left hemisphere of the cerebellum and part of the right hemisphere have been removed to show the inside of the fourth ventricle and the cerebellar peduncles. Part (d) shows a cross section of the midbrain. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.25 Ventral View of the Spinal Column Details show the anatomy of the bony vertebrae. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-48 Figure 3.26 Ventral View of the Spinal Cord 3-49 The figure shows (a) a portion of the spinal cord, showing the layers of the meninges and the relationship of the spinal cord to the vertebral column; and (b) a cross section through the spinal cord. Ascending tracts are shown in blue; descending tracts are shown in red. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-50 Structure and Function of the Peripheral Nervous System (PNS) (1 of 3) • Cranial Nerves – Cranial nerves attached to ventral surface of brain – Most serve sensory and motor functions of head and neck region – Vagus nerve regulates functions of organs in thoracic and abdominal cavities Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-51 Structure and Function of the Peripheral Nervous System (PNS) (2 of 3) • Spinal Nerves – Afferent Axon – Dorsal Root Ganglion – Efferent Axon (eff ur ent) • Somatic Nervous System • Autonomic Nervous System (ANS) Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-52 Structure and Function of the Peripheral Nervous System (PNS) (3 of 3) • Sympathetic Division – Portion of autonomic nervous system that controls functions that accompany arousal and expenditure of energy • Parasympathetic Division – Portion of autonomic nervous system that controls functions that occur during relaxed state Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. Figure 3.27 The Cranial Nerves 3-53 The twelve pairs of cranial nerves serve regions in the head, neck, and thoracic and abdominal cavities. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved. 3-54 Figure 3.28 Cross Section of the Spinal Cord The figure shows the routes taken by afferent and efferent axons through the dorsal and ventral roots. Copyright © 2017, 2013, 2010 by Pearson Education, Inc. All rights reserved.
