DOCSLIB.ORG

The Nervous System 9/24/2009

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Nervous System 9/24/2009 COGS17 ‐ 01‐The Nervous System 9/24/2009 The Nervous System Mary ET Boyle, Ph.D. Department of Cognitive Science UCSD What’s the big deal? 1 COGS17 ‐ 01‐The Nervous System 9/24/2009 Detect Evaluate Decide Respond Analysis of the nervous system to understand the biological basis for behavior. Modern studies ◦ Neuroanatomists ◦ Neurochemists ◦ Neurophysiologists ◦ Neuropsychologists Neuroscience – term introduced in mid-1960s 2 COGS17 ‐ 01‐The Nervous System 9/24/2009 The brain must know what is happening outside in the environment. •perceive •remember •decide •act sensory neurons motor neurons interneurons Peripheral Nervous System (PNS) Central Nervous System ( CNS) Organization 3 COGS17 ‐ 01‐The Nervous System 9/24/2009 Detects/processes environmental stimuli: Somatic Nervous System Regulates internal organs: Autonomic Nervous System Organization of PNS Detects environmental stimuli: Somatic Nervous System Regulates internal organs: Autonomic Nervous System Decision! Central nervous system 4 COGS17 ‐ 01‐The Nervous System 9/24/2009 Brain Spinal Cord Components of the CNS 5 COGS17 ‐ 01‐The Nervous System 9/24/2009 Anterior Posterior Dl Left Dorsal Right Ventral Anatomical directions 6 COGS17 ‐ 01‐The Nervous System 9/24/2009 Horizontal section— Shows structures viewed from above/below 7 COGS17 ‐ 01‐The Nervous System 9/24/2009 Sagittal section— Divides structures into right and left parts Coronal section (frontal section)— Shows views from the front/back 8 COGS17 ‐ 01‐The Nervous System 9/24/2009 Review of Anatomical Directions Anterior—toward the front (e.g., dog’ s nose) Posterior—toward the rear (e.g., dog’s tail) Ventral—toward the belly Dorsal—toward the back Rostral—toward the head Caudal—toward the tail Medial—toward the midline Lateral—away from the midline Superior—above a structure Inferior—below a structure Fundamental cellular unit Purpose of neurons: ◦ receive ◦ process ◦ transfer Information is made up of chemical or electrical signals Unidirectional Neurons 9 COGS17 ‐ 01‐The Nervous System 9/24/2009 Neurobiology of Cognition COGS 17 Neurobiology of Cognition COGS 17 10 COGS17 ‐ 01‐The Nervous System 9/24/2009 Four major types of synapses 11 COGS17 ‐ 01‐The Nervous System 9/24/2009 Three types of neurons Some multipolar neurons 12 COGS17 ‐ 01‐The Nervous System 9/24/2009 Support Staff: Glia More than just glue? Glia, short for neuroglial cells. Their purpose is to provide metabolic support, insulate, protect, reinforce, repair, and cleanup damaged areas. Mounting evidence suggests that glial cells may be nearly as critical to thinking and learning as neurons are. Glia 13 COGS17 ‐ 01‐The Nervous System 9/24/2009 are much more numerous than neurons. outnumber neurons 2:1. are found in both the CNS and PNS. Neuroglia means “nerve glue. ” Researchers have found that the average human cerebral cortex has approximately two glial cells for every neuron (other brain regions have up to 10 times as many). That’s a glia index of 2.0. The index in comparable regions in rodents is 0.4, in worms 0.17. There is work that supports the theory that a high concentration of glia may actually boost the ability to think. So here’s something to think about: the glia index in the cerebral cortex of dolphins is 3.0. Glia … 14 COGS17 ‐ 01‐The Nervous System 9/24/2009 protoplasmic astrocytes fibrous astrocytes Basic classification of glial cells microglial cells oligodendrocytes Spanish anatomist Pío del Río Hortega classified these cells. Hortega made these drawings in 1920 with the help of a microscope’s camera lucida. 15 COGS17 ‐ 01‐The Nervous System 9/24/2009 Neurobiology of Cognition COGS 17 Multiple sclerosis (MS) is a progressive central nervous system disorder. Localized oligodendrocyte demyelination prevents affected nerve cells from functioning properly. In some cases, the demyelinated axons completely fail to work. 16 COGS17 ‐ 01‐The Nervous System 9/24/2009 Neurobiology of Cognition COGS 17 17 COGS17 ‐ 01‐The Nervous System 9/24/2009 Neurobiology of Cognition COGS 17 Glia and neurons work together Neurobiology of Cognition COGS 17 18 COGS17 ‐ 01‐The Nervous System 9/24/2009 Neurobiology of Cognition COGS 17 Neurobiology of Cognition Zlokovic & Apuzzo: Neurosurgery 43(4):877-878, 1998. COGS 17 19 COGS17 ‐ 01‐The Nervous System 9/24/2009 (PNS) Peripheral Nervous System The Autonomic The Somatic Nervous System Nervous System Enables one to The Somatic interact with the Nervous System physical environment. Two types of nerves: Efferent Afferent Cranial Spinal neurons take neurons bring messages from messages from the CNS to the sensory skeletal muscles receptors to the CNS 20 COGS17 ‐ 01‐The Nervous System 9/24/2009 Table 2.1: Klein/Thorne: Biological Psychology © 2007 by Worth Publishers 21 COGS17 ‐ 01‐The Nervous System 9/24/2009 Efferent neurons The Autonomic control glandular Nervous System activityy and internal organ functioning. Two divisions: Sympathetic Parasympathetic ShiSympathetic Prepares the organism to respond to challenging or dangerous conditions. 22 COGS17 ‐ 01‐The Nervous System 9/24/2009 CNS protection 23 COGS17 ‐ 01‐The Nervous System 9/24/2009 Ventricular System 24 COGS17 ‐ 01‐The Nervous System 9/24/2009 CNS: spinal cord 25 COGS17 ‐ 01‐The Nervous System 9/24/2009 Three main functions: ◦ Recognizing detected stimuli ◦ Analyzing the information ◦ Executing the appropriate response The Central Nervous System: The Brain 26 COGS17 ‐ 01‐The Nervous System 9/24/2009 Myelencephalon—contains the medulla oblongata, which controls basic life functions (e.g., respiration, heart rate, vomiting, salivation Reticular formation (reticular activating system)—begins in the medulla, extends to other areas of the brain and is involved in arousal Metencephalon consists of two major structures: ◦ Pons—a “bridge” for many fibers passing from one side of the brain to the other. Sensory fibers, fibers from the cortex to cerebellum, and fibers that relay information on sleep, arousal and dreaming pass through it. ◦ Cerebellum—involved in the development and coordination of movement Raphé system—plays a role in sleep and arousal Hindbrain Midbrain - mesencephalon 27 COGS17 ‐ 01‐The Nervous System 9/24/2009 Tectum (“roof”) relays visual and auditory information and controls simple reflexes, eye and ear orientation movements superior colliculi (“little hills”)—relays visual information inferior colliculi—relays auditory information Tegmentum (“floor covering”) substantia nigra—integration of voluntary movements red nucleus —controls basic body movements reticular formation —controls arousal and consciousness brain stem—midbrain + hindbrain (minus the cerebellum) 28 COGS17 ‐ 01‐The Nervous System 9/24/2009 Thalamus—major relay station for sensory information Medial geniculate nucleus (MGN)—relays auditory information Lateral geniculate nucleus (LGN)—relays visual information Other nuclei connect to areas not involved in sensation, e.g., the ventrolateral nucleus receives information from the cerebellum and relays it to the motor cortex. 29 COGS17 ‐ 01‐The Nervous System 9/24/2009 Hypothalamus—detects need states (e.g., hunger and thirst), controls the autonomic nervous system, and controls pituitary hormone production and release The suprachiasmatic nucleus of the hypothalamus also is involved in the control of biological rhythms. Pituitary gland (hypophysis)—regulates other glandular activity of the body (often called the “master gland”) Anterior pituitary gland (adenohypophysis)—produces several hormones including somatotropin, thyrotropin, adrenocorticotropin, and the gonadotropins Posterior pituitary (neurohypophysis)—releases oxytocin and antidiuretichormone (ADH) which are produced in the hypothalamus 30 COGS17 ‐ 01‐The Nervous System 9/24/2009 Limbic System The limbic system governs emotions such as anger, happiness, and fear and is involved in the storage and retrieval of memories. The limbic system is a group of structures surrounding the brain stem. The limbic system structures include the amygdala, cingulate gyrus, and hippocampus. Basal Ganglia— have widespread connections to the cortex and forebrain and are involved in the initiation of voluntary movements, maintaining muscle tone and posture Parts of the basal ganglia include: The caudate nucleus, the putamen, and the globus pallidus The caudate nucleus and the putamen are referred to as the corpus striatum due to their appearance. 31 COGS17 ‐ 01‐The Nervous System 9/24/2009 32 COGS17 ‐ 01‐The Nervous System 9/24/2009 Somatosensory cortex —anterior portion of the parietal lobe. Motor cortex —area of the frontal lobe anterior to the central sulcus. The face and hands have a large amount of representation in these areas. This representation allows for great sensitivity and motor control for these areas of the body. 33 COGS17 ‐ 01‐The Nervous System 9/24/2009 34 COGS17 ‐ 01‐The Nervous System 9/24/2009 35 COGS17 ‐ 01‐The Nervous System 9/24/2009 Neurons—Perform information processing and communications functions of the nervous system ◦ Consist of three major parts: 1. Soma (cell body)—contains nucleus, mitochondria, and ribosomes 2. Dendrites—portions of the neuron that transmit information toward the cell body (typically) 3. Axon—a structure on the neuron which transmits information away from the cell body Terms review sensory neuron ◦ A neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system. ◦ Sensory neurons carry information to the CNS motor neuron ◦ A neuron locat
Load more

Recommended publications
  • Biophysical Network Modelling of the Dlgn Circuit: Different Effects of Triadic and Axonal Inhibition on Visual Responses of Relay Cells
    RESEARCH ARTICLE Biophysical Network Modelling of the dLGN Circuit: Different Effects of Triadic and Axonal Inhibition on Visual Responses of Relay Cells Thomas Heiberg1, Espen Hagen1,2, Geir Halnes1, Gaute T. Einevoll1,3* 1 Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway, 2 Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and a11111 JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany, 3 Department of Physics, University of Oslo, Oslo, Norway * [email protected] Abstract OPEN ACCESS Despite its prominent placement between the retina and primary visual cortex in the early Citation: Heiberg T, Hagen E, Halnes G, Einevoll GT visual pathway, the role of the dorsal lateral geniculate nucleus (dLGN) in molding and regu- (2016) Biophysical Network Modelling of the dLGN lating the visual signals entering the brain is still poorly understood. A striking feature of the Circuit: Different Effects of Triadic and Axonal Inhibition on Visual Responses of Relay Cells. PLoS dLGN circuit is that relay cells (RCs) and interneurons (INs) form so-called triadic synapses, Comput Biol 12(5): e1004929. doi:10.1371/journal. where an IN dendritic terminal can be simultaneously postsynaptic to a retinal ganglion cell pcbi.1004929 (GC) input and presynaptic to an RC dendrite, allowing for so-called triadic inhibition. Taking Editor: Arnd Roth, University College London, advantage of a recently developed biophysically detailed multicompartmental model for an UNITED KINGDOM IN, we here investigate putative effects of these different inhibitory actions of INs, i.e., triadic Received: August 29, 2015 inhibition and standard axonal inhibition, on the response properties of RCs.
    [Show full text]
  • From Human Emotions to Robot Emotions
    1 American Association for Artificial Intelligence – Spring Symposium 3/2004, Stanford University – Keynote Lecture. From Human Emotions to Robot Emotions Jean-Marc Fellous The Salk Institute for Neurobiological Studies 10010 N. Torrey Pines Road, la Jolla, CA 92037 [email protected] Abstract1 open a new window on the neural bases of emotions that may offer new ways of thinking about implementing robot- The main difficulties that researchers face in understanding emotions. emotions are difficulties only because of the narrow- mindedness of our views on emotions. We are not able to Why are emotions so difficult to study? free ourselves from the notion that emotions are necessarily human emotions. I will argue that if animals have A difficulty in studying human emotions is that here are emotions, then so can robots. Studies in neuroscience have significant individual differences, based on experiential as shown that animal models, though having limitations, have well as genetic factors (Rolls, 1998; Ortony, 2002; significantly contributed to our understanding of the Davidson, 2003a, b; Ortony et al., 2004). My fear at the functional and mechanistic aspects of emotions. I will sight of a bear may be very different from the fear suggest that one of the main functions of emotions is to experienced by a park-ranger who has a better sense for achieve the multi-level communication of simplified but high impact information. The way this function is achieved bear-danger and knows how to react. My fear might also be in the brain depends on the species, and on the specific different from that of another individual who has had about emotion considered.
    [Show full text]
  • Distribution of Immunoreactive ,&Neo
    0270-6474/84/0405-1248$02.00/O The Journal of Neuroscience Copyright 0 Society for Neuroscience Vol. 4, No. 5, pp. 1248-1252 Printed in U.S.A. May 1984 DISTRIBUTION OF IMMUNOREACTIVE ,&NEO-ENDORPHIN IN DISCRETE AREAS OF THE RAT BRAIN AND PITUITARY GLAND: COMPARISON WITH a-NEO-ENDORPHIN NADAV ZAMIR,’ MIKLOS PALKOVITS, AND MICHAEL J. BROWNSTEIN Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, Maryland 20205 Received August 5, 1983; Revised December 2, 1983; Accepted December 2, 1983 Abstract The distribution of immunoreactive (ir)-P-neo-endorphin in 101 miscrodissected rat brain and spinal cord regions as well as in the neurointermediate lobe of pituitary gland was determined using a highly specific radioimmunoassay. The highest concentration of P-neo-endorphin in brain was found in the median eminence (341.4 fmol/mg of protein). High concentrations of ir-/3-neo- endorphin (>250 fmol/mg of protein) were found in 11 nuclei, including dorsomedial nucleus, substantia nigra, parabrachial nuclei, periaqueductal gray matter, anterior hypothalamic nucleus, and lateral preoptic areas. Moderate concentrations of the peptide (between 100 and 250 fmol/mg of protein) were found in 66 brain nuclei such as the amygdaloid and septal nuclei, most of the diencephalic structures (not including the hypothalamus), and the majority of the medulla oblongata nuclei and others. Low concentrations of ir-P-neo-endorphin (Cl00 fmol/mg of protein) were found in 21 nuclei, e.g., cortical structures (frontal., cingulate, piriform, parietal, entorhinal, occipital), olfactory tubercle, and cerebellum (nuclei and cortex). The olfactory bulb has the lowest /3-neo- endorphin concentration (21.3 fmol/mg of protein).
    [Show full text]
  • What Can Be Learned from White Matter Alterations in Antisocial Girls Willeke M
    Menks WM, Raschle NM. J Neurol Neuromedicine (2017) 2(7): 16-20 Neuromedicine www.jneurology.com www.jneurology.com Journal of Neurology & Neuromedicine Mini Review Open Access What can be learned from white matter alterations in antisocial girls Willeke M. Menks1, Christina Stadler1 and Nora M. Raschle1 1Department of Child and Adolescent Psychiatry, University of Basel, Psychiatric University Hospital Basel, Switzerland. Article Info ABSTRACT Article Notes Antisocial behavior in youths constitutes a major public health problem Received: June 17, 2017 worldwide. Conduct disorder is a severe variant of antisocial behavior with higher Accepted: July 31, 2017 prevalence rates for boys (12%) as opposed to girls (7%). A better understanding *Correspondence: of the underlying neurobiological mechanisms of conduct disorder is warranted Dr. Willeke Menks, PhD to improve identification, diagnosis, or treatment. Functional and structural Department of Child and Adolescent Psychiatry (KJPK), neuroimaging studies have indicated several key brain regions within the limbic Psychiatric University Clinics Basel (UPK) system and prefrontal cortex that are altered in youths with conduct disorder. Schanzenstrasse 13, CH-4056 Basel, Switzerland Examining the structural connectivity, i.e. white matter fiber tracts connecting Tel. +41 61 265 89 76 these brain areas, may further inform about the underlying neural mechanisms. Fax +41 61 265 89 61 Diffusion tensor imaging (DTI) is a non-invasive technique that can evaluate the © 2017 Menks WM & Raschle NM. This article is distributed white matter integrity of fiber tracts throughout the brain. To date, DTI studies have under the terms of the Creative Commons Attribution 4.0 found several white matter tracts that are altered in youths with conduct disorder.
    [Show full text]
  • The Bright Pituitary Gland-A Normal MR Appearance in Infancy
    The Bright Pituitary Gland-A Normal MR Appearance in Infancy Samuel M. Wolpert' Signal intensities of the pituitary gland were measured on T1 -weighted sagittal MR Mark Osborne2 images of 25 patients younger than 20 years old. We found that the signal intensities in Mary Anderson' the eight patients who were 8 weeks old or younger were higher (shorter T1) than those Val M. Runge2 in the 17 older patients. We also noted a difference in the signal intensities across the pituitary gland, the signal being higher in the posterior part of the gland than in the anterior part. We attribute the high signal intensities to the rapid intrauterine pituitary growth, so that at term pituitary protein synthetic activity is at a maximum. Possibly, an increase in the bound fraction of the water molecules of the gland may also be present in the neonatal pituitary as compared with the older gland, but this remains to be proved. The higher signal in the posterior pituitary gland may be due to lipid in the pituicyte cells of the posterior pituitary gland. The signal intensity of the contents of the sella turcica on T1-weighted MR images is not always uniform and homogeneous., Often , a high-intensity crescent­ shaped structure is seen oriented along the posterior-inferior margin of the sella turcica. Some believe this to be fat in the sella turcica but behind the gland [1]. Others think that the high intensity is derived from the posterior pituitary itself [2 , 3]. There are no published observations about the MR appearance of the pituitary gland in infants and children .
    [Show full text]
  • Nervous Tissue
    Department of Histology and Embryology Medical faculty KU Bratislava NERVOUS TISSUE RNDr. Mária Csobonyeiová, PhD ([email protected]) Nerve tissue neurons /main cells/ (perikaryon = cell body=soma,dendrites,axon), 4 -150 µm glial cells /supporting cells/ - 10 times more abudant CNS- oligodendrocytes, astrocytes, ependymal cells,microglia PNS - Schwann cells, satelite cells Neuron independentNeuron anatomical and functional unit responsible for: receiving of different types of stimuli transducing them into the nerve impulses conducting them to the nerve centers development – embryonal neuroectoderm Morphology of the neurons Pseudounipolar neuron! (spinal ganglion) Methods used in neurohistology Staining methods: Luxol blue and cresyl violet (nucleus+nucleolus+Nissl body) Luxol blue (myelin sheath) and nuclear red (nucleus + nucleolus+Nissl body) Impregnations according - Holmes – neurons, axon, dendrites - neurofibrils (brown-violet) Golgi – neurons + astrocytes (black) with golden background Cajal – astrocytes (black) with red background Rio del Hortega – microglia (black) with gray-violet background OsO4 - myelin sheath (black), staining for lipids and lipoproteins (myelin) Microglia (phagocytosis) Astrocytes (supporting role, Oligodendrocytes nutrition, healing (formation of myelin of defects - glial sheath) scars, formation of BBB) Ependymal cells (regulation of stable chemical constitution of CSF) CSN Gray matter: White matter: - bodies of neurons, dendrites - myelinated and unmyelinated axons - initial portion
    [Show full text]
  • Shh/Gli Signaling in Anterior Pituitary
    SHH/GLI SIGNALING IN ANTERIOR PITUITARY AND VENTRAL TELENCEPHALON DEVELOPMENT by YIWEI WANG Submitted in partial fulfillment of the requirements For the degree of Doctor of Philosophy Department of Genetics CASE WESTERN RESERVE UNIVERSITY January, 2011 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of _____________________________________________________ candidate for the ______________________degree *. (signed)_______________________________________________ (chair of the committee) ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ (date) _______________________ *We also certify that written approval has been obtained for any proprietary material contained therein. TABLE OF CONTENTS Table of Contents ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• i List of Figures ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• v List of Abbreviations •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• vii Acknowledgements •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• ix Abstract ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• x Chapter 1 Background and Significance ••••••••••••••••••••••••••••••••••••••••••••••••• 1 1.1 Introduction to the pituitary gland
    [Show full text]
  • L03 Neurons to Post.Key
    Vert Phys PCB3743 Neurons Fox Chapter 7 pt 1 © T. Houpt, Ph.D. Structure of Vertebrates Two major compartments of the body Peripheral Compartment Everything outside of the brain and spinal cord (heart, lungs, gastrointestinal tract, liver, kidneys, skeletal muscle, skin etc.) Central Nervous System (CNS) • Brain at front of body • Spinal cord running down the back • Protected by skull and vertebra • Sensory receptors clustered in head (vision, hearing, taste, smell) T http://bookdome.com/health/anatomy/Human-Body/Man-Is-A-Vertebrate-Animal.html Vertebrate Central Nervous System: brain & spinal cord cerebellum cerebrum back brainstem Vertebra Skull spinal cord head tail GI tract stomach Vertebrate Central Nervous System: brain & spinal cord cerebellum cerebrum back brainstem spinal cord head tail GI tract stomach Peripheral Nervous System: Neurons and nerve fibers outside the brain and spinal cord back motor neurons sensory ganglion autonomic ganglion head autonomic motor sensory tail nerve nerve nerve GI tract enteric NS stomach Functions of the Nervous System Sensory Motor Integration Detect changes in the environment or in the body via sensory receptors; coordinate responses across the body. Initiate responses via skeletal muscle (somatic nerves for voluntary movement) or via smooth muscle and glands (autonomic nervous system). Neurons (nerve cells) Point to point communication across the body to coordinate responses Integrate electrical and chemical signals at dendrites & cell body; depending on inputs, neuron sends electrical and chemical signal down axon to synapse on target cell. Sensory neurons (afferents) carry sensory information into the CNS Motor neurons (efferents) carry impulses out of CNS to make muscles move or effect target organs (e.g.
    [Show full text]
  • Synaptic Ultrastructure of Functionally and Morphologically Characterized Neurons of the Superficial Spinal Dorsal Horn Cat
    The Journal of Neuroscience, June 1989, g(8): 1848-l 883 Synaptic Ultrastructure of Functionally and Morphologically Characterized Neurons of the Superficial Spinal Dorsal Horn Cat M. Wthelyi, A. R. Light, and E. Ft. Per1 Department of Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, and Second Department of Anatomy, Semmelweis University, Budapest, Hungary Recordings of neuronal unitary discharges evoked by pri- neurons, regardless of gross configuration, were found to mary afferent input were made in the superficial part of the have vesicles in their dendrites, but 3 nocireceptiveneurons spinal cord’s dorsal horn, the marginal zone and substantia received synapses from presynaptic dendritic profiles. gelatinosa (also known as laminae I and II) , using fine mi- cropipette electrodes filled with HRP. After physiological The superficial dorsal horn, laminae I and II, of the spinal cord characterization with respect to primary afferent input, HRP (Brown and Rethelyi, 1981) receivesprimary afferent input prin- was injected intracellularly iontophoretically into the record- cipally or exclusively from fine fibers, myelinated and unmy- ed neuron. Following histochemical processing, the neurons elinated, that pass through the lateral division of the dorsal so delineated were studied at the light and electron micro- rootlets (Sindou et al., 1974; Snyder, 1977; Light and Perl, 1979a, scopic levels. No clear relationship between function and b). However, from the functional standpoint, the input to the either general cellular configuration or synaptic ultrastruc- region from the periphery is diverse (Kumazawa and Perl, 1978; ture appeared in these analyses, although the concentration Rethelyi et al., 1979; Perl, 1984). There have been numerous of dendritic distribution could be related to the nature of descriptions of the structure of neurons and terminal axon sys- primary afferent excitation.
    [Show full text]
  • Andrew Rosen the Architecture of the Nervous System: • Central Nervous
    Andrew Rosen The Architecture of the Nervous System: Central Nervous System (CNS) – Includes the brain and spinal cord Peripheral Nervous System (PNS) – All nerves elsewhere and are connected to the CNS via the spinal cord o Composed of the Somatic Nervous System (SNS), which has the efferent nerves that control the skeletal muscles and afferent nerves that carry information from the sense organs to CNS o Also composed of the Autonomous Nervous System (ANS), which has the efferent nerves that regulate the glands and smooth muscles of internal organs and vessels as well as afferent nerves that bring the CNS information about the internal systems . Divided into the sympathetic branch “Revs” body up for an action . Also divided into parasympathetic branch Restores the body’s internal activities to normal after an action Brain is in cerebrospinal fluid that acts as a shock absorber Anatomy of the Brain: Spinal cord that goes into brain forms the brain stem Medulla is at the bottom of the brain stem o Controls breathing, blood circulation, and maintains balance Pons is above the medulla o Controls attentiveness and governs sleep/dreaming Behind the brain stem is the cerebellum o Controls balance, coordination, and spatial reasoning The midbrain and thalamus are on top of the pons o Relay information to the forebrains o Midbrain regulates experience of pain and moods The forebrain is on top of all of these o Outer part of the forebrain is the cerebral cortex . High surface area . Deepest groove is the longitudinal fissure that splits the left cerebral hemisphere from the right .
    [Show full text]
  • Hypothalamus - Wikipedia
    Hypothalamus - Wikipedia https://en.wikipedia.org/wiki/Hypothalamus The hypothalamus is a portion of the brain that contains a number of Hypothalamus small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system.[1] In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is the size of an almond. The hypothalamus is responsible for the regulation of certain metabolic processes and other activities of the autonomic nervous system. It synthesizes and secretes certain neurohormones, called releasing hormones or hypothalamic hormones, Location of the human hypothalamus and these in turn stimulate or inhibit the secretion of hormones from the pituitary gland. The hypothalamus controls body temperature, hunger, important aspects of parenting and attachment behaviours, thirst,[2] fatigue, sleep, and circadian rhythms. The hypothalamus derives its name from Greek ὑπό, under and θάλαμος, chamber. Location of the hypothalamus (blue) in relation to the pituitary and to the rest of Structure the brain Nuclei Connections Details Sexual dimorphism Part of Brain Responsiveness to ovarian steroids Identifiers Development Latin hypothalamus Function Hormone release MeSH D007031 (https://meshb.nl Stimulation m.nih.gov/record/ui?ui=D00 Olfactory stimuli 7031) Blood-borne stimuli
    [Show full text]
  • Normal Cells of Cns
    NORMAL CELLS OF CNS OBJECTIVES: At the end of this lecture, you should describe the microscopic structure and the function of: 1- Neurons: - Cell body (perikaryon). - Processes: An axon and dendrites. 2- Neuroglia: - Astrocytes. - Oligodendrocytes. - Microglia. - Ependymal cells. Neuron Components: 1. Cell body (Perikaryon) 2. Processes : a. An axon: only one b. Dendrites: one or more TYPES OF NEURONS Based on number of processes 1. Pseudounipolar neurons. 2. Bipolar neurons. 3. Multipolar neurons. TYPES OF NEURONS Based on number of processes 1. Unipolar (Pseudounipolar) neuron (rounded neuron): Has one process only, that divides into two branches; one Dendrite acts as a dendrite and the other as an axon. e.g. Mesencephalic nucleus of Axon trigeminal nerve and dorsal root (spinal) ganglion. TYPES OF NEURONS Based on number of processes 2. Bipolar Neuron (spindle-shaped neuron): Has two processes (one arising from each pole of the cell body). One of them is the dendrite and the other is the axon, e.g. retina & Dendrite olfactory epithelium. TYPES OF NEURONS Based on number of processes 3. Multipolar neuron: Has one axon and multiple dendrites. Types of multipolar neurons: A. Stellate neuron: • The commonest type. • Distributed in most areas of CNS, e.g. anterior horn cells of the spinal cord TYPES OF NEURONS Based on number of processes B. Pyramidal neurons: • Distributed in motor area 4 of the cerebral cortex. C. Pyriform neurons: • Pear-shaped, e.g. Purkinje cells of cerebellar cortex CELL BODY (Perikaryon) Structure of cell body: 1. Nucleus: • Single, usually central, rounded and vesicular with prominent nucleolus. 2. Cytoplasm. CELL BODY (Perikaryon) Cytoplasm: Its main components include: 1.
    [Show full text]