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Crayfish Escape Behavior and Central Synapses
Crayfish Escape Behavior and Central Synapses. III. Electrical Junctions and Dendrite Spikes in Fast Flexor Motoneurons ROBERT S. ZUCKER Department of Biological Sciences and Program in the Neurological Sciences, Stanford University, Stanford, California 94305 THE LATERAL giant fiber is the decision fiber and fast flexor motoneurons are located in for a behavioral response in crayfish in- the dorsal neuropil of each abdominal gan- volving rapid tail flexion in response to glion. Dye injections and anatomical recon- abdominal tactile stimulation (27). Each structions of ‘identified motoneurons reveal lateral giant impulse is followed by a rapid that only those motoneurons which have tail flexion or tail flip, and when the giant dentritic branches in contact with a giant fiber does not fire in response to such stim- fiber are activated by that giant fiber (12, uli, the movement does not occur. 21). All of tl ie fast flexor motoneurons are The afferent limb of the reflex exciting excited by the ipsilateral giant; all but F4, the lateral giant has been described (28), F5 and F7 are also excited by the contra- and the habituation of the behavior has latkral giant (21 a). been explained in terms of the properties The excitation of these motoneurons, of this part of the neural circuit (29). seen as depolarizing potentials in their The properties of the neuromuscular somata, does not always reach threshold for junctions between the fast flexor motoneu- generating a spike which propagates out the rons and the phasic flexor muscles have also axon to the periphery (14). Indeed, only t,he been described (13). -
Long-Term Adult Human Brain Slice Cultures As a Model System to Study
TOOLS AND RESOURCES Long-term adult human brain slice cultures as a model system to study human CNS circuitry and disease Niklas Schwarz1, Betu¨ l Uysal1, Marc Welzer2,3, Jacqueline C Bahr1, Nikolas Layer1, Heidi Lo¨ ffler1, Kornelijus Stanaitis1, Harshad PA1, Yvonne G Weber1,4, Ulrike BS Hedrich1, Ju¨ rgen B Honegger4, Angelos Skodras2,3, Albert J Becker5, Thomas V Wuttke1,4†*, Henner Koch1†* 1Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tu¨ bingen, Tu¨ bingen, Germany; 2Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tu¨ bingen, Tu¨ bingen, Germany; 3German Center for Neurodegenerative Diseases (DZNE), Tu¨ bingen, Germany; 4Department of Neurosurgery, University of Tu¨ bingen, Tu¨ bingen, Germany; 5Department of Neuropathology, Section for Translational Epilepsy Research, University Bonn Medical Center, Bonn, Germany Abstract Most of our knowledge on human CNS circuitry and related disorders originates from model organisms. How well such data translate to the human CNS remains largely to be determined. Human brain slice cultures derived from neurosurgical resections may offer novel avenues to approach this translational gap. We now demonstrate robust preservation of the complex neuronal cytoarchitecture and electrophysiological properties of human pyramidal neurons *For correspondence: in long-term brain slice cultures. Further experiments delineate the optimal conditions for efficient [email protected] viral transduction of cultures, enabling ‘high throughput’ fluorescence-mediated 3D reconstruction tuebingen.de (TVW); of genetically targeted neurons at comparable quality to state-of-the-art biocytin fillings, and [email protected] demonstrate feasibility of long term live cell imaging of human cells in vitro. -
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 -
Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal. -
Polyribosomes Associated with Synaptic Specializations on Axon Initial Segments: Localization of Protein-Synthetic Machinery at Inhibitory Synapses
The Journal of Neuroscience October 1986, 6(10): 3079-3085 Polyribosomes Associated with Synaptic Specializations on Axon Initial Segments: Localization of Protein-Synthetic Machinery at Inhibitory Synapses Oswald Steward* and Charles E. Ribak-f *Departments of Neurosurgery and Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, and TDepartment of Anatomy and Neurobiology, University of California at Irvine, Irvine, California 92717 Previous studies have revealed a selective association between report that showed some axonal ribosomes grouped at points polyribosomes and axospinous synapses in a variety of brain of branching and beneath synaptic contacts (Jones and Powell, regions. The present study evaluates whether polyribosomes are 1969). Therefore, they were usually considered, only in passing, also associated with the symmetrical and presumably inhibitory as exceptions to the rule. Thus, it has come to be accepted as a synaptic connections found on the initial segment of axons of central tenet that essentially all of the protein constituents of some neurons in the CNS. The initial segments of pyramidal the neuron, including those required for synaptic specializations, neurons in the sensorimotor cortex of the monkey and of granule were synthesized in the cell body, and somehow selectively cells in the hippocampus of the rat were examined. The initial transported to the sites at which they would be assembled (for segments of these cell types are contacted by GABAergic ter- a review, see Grafstein and Forman, 1980). minals that form symmetrical synaptic connections. In the pres- Over the past few years, a series of observations has given ent study, these initial segments were found to contain polyri- rise to an hypothesis that challenges the prevailing view that bosomes that tended to be selectively localized beneath the virtually all neuronal proteins are produced in the cell body and synaptic specializations. -
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. -
The Narrowing of Dendrite Branches Across Nodes Follows a Well-Defined Scaling Law
The narrowing of dendrite branches across nodes follows a well-defined scaling law Maijia Liaoa, Xin Liangb, and Jonathon Howarda,1 aDepartment of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520; and bTsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China Edited by Yuh Nung Jan, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, and approved May 17, 2021 (received for review October 28, 2020) The systematic variation of diameters in branched networks has minimized. Da Vinci’s law has been reformulated as the “pipe tantalized biologists since the discovery of da Vinci’s rule for trees. model” for plants, in which a fixed cross-section of stems and Da Vinci’s rule can be formulated as a power law with exponent branches is required to support each unit amount of leaves (13). two: The square of the mother branch’s diameter is equal to the Experimental support for scaling laws, however, is scarce because sum of the squares of those of the daughters. Power laws, with of the difficulties of imaging entire branched networks and because different exponents, have been proposed for branching in circula- intrinsic anatomical variability may obscure precise laws (14). Thus, tory systems (Murray’s law with exponent 3) and in neurons (Rall’s it is an open question whether scaling laws such as Eq. 1 apply in law with exponent 3/2). The laws have been derived theoretically, biological systems. based on optimality arguments, but, for the most part, have not To quantitatively test diameter-scaling laws in neurons, it is been tested rigorously. -
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. -
NEURAL CONNECTIONS: Some You Use, Some You Lose
NEURAL CONNECTIONS: Some You Use, Some You Lose by JOHN T. BRUER SOURCE: Phi Delta Kappan 81 no4 264-77 D 1999 . The magazine publisher is the copyright holder of this article and it is reproduced with permission. Further reproduction of this article in violation of the copyright is prohibited JOHN T. BRUER is president of the James S. McDonnell Foundation, St. Louis. This article is adapted from his new book, The Myth of the First Three Years (Free Press, 1999), and is reprinted by arrangement with The Free Press, a division of Simon Schuster Inc. ©1999, John T. Bruer . OVER 20 YEARS AGO, neuroscientists discovered that humans and other animals experience a rapid increase in brain connectivity -- an exuberant burst of synapse formation -- early in development. They have studied this process most carefully in the brain's outer layer, or cortex, which is essentially our gray matter. In these studies, neuroscientists have documented that over our life spans the number of synapses per unit area or unit volume of cortical tissue changes, as does the number of synapses per neuron. Neuroscientists refer to the number of synapses per unit of cortical tissue as the brain's synaptic density. Over our lifetimes, our brain's synaptic density changes in an interesting, patterned way. This pattern of synaptic change and what it might mean is the first neurobiological strand of the Myth of the First Three Years. (The second strand of the Myth deals with the notion of critical periods, and the third takes up the matter of enriched, or complex, environments.) Popular discussions of the new brain science trade heavily on what happens to synapses during infancy and childhood. -
How Do Dendrites Take Their Shape?
© 2001 Nature Publishing Group http://neurosci.nature.com review How do dendrites take their shape? Ethan K. Scott1 and Liqun Luo1,2 1 Department of Biological Sciences, Stanford University, Stanford, California 94305, USA 2 Neurosciences Program, Stanford University, Stanford, California 94305, USA Correspondence should be addressed to L.L. ([email protected]) Recent technical advances have made possible the visualization and genetic manipulation of individual dendritic trees. These studies have led to the identification and characterization of molecules that are important for different aspects of dendritic development. Although much remains to be learned, the existing knowledge has allowed us to take initial steps toward a comprehensive understanding of how complex dendritic trees are built. In this review, we describe recent advances in our understanding of the molecular mechanisms underlying dendritic morphogenesis, and discuss their cell-biological implications. With their great complexity and variety, dendrites (Fig. 1) are won- added advantage, can be used to study loss-of-function muta- ders of nature’s design. Built to receive and integrate inputs to neu- tions. Much of the progress reviewed in this article would not rons, dendrites occupy much of the brain’s volume and have been have been possible without these technological advances. the subject of studies since the days of Golgi and Cajal1. Over the course of much of the twentieth century, the prevailing belief that Breaking down complex dendritic trees axons take the more active role in wiring the brain and in estab- Although the processes used to build dendritic trees are complex lishing synaptic specificity led researchers to focus on the develop- and diverse (Fig. -
11 Introduction to the Nervous System and Nervous Tissue
11 Introduction to the Nervous System and Nervous Tissue ou can’t turn on the television or radio, much less go online, without seeing some- 11.1 Overview of the Nervous thing to remind you of the nervous system. From advertisements for medications System 381 Yto treat depression and other psychiatric conditions to stories about celebrities and 11.2 Nervous Tissue 384 their battles with illegal drugs, information about the nervous system is everywhere in 11.3 Electrophysiology our popular culture. And there is good reason for this—the nervous system controls our of Neurons 393 perception and experience of the world. In addition, it directs voluntary movement, and 11.4 Neuronal Synapses 406 is the seat of our consciousness, personality, and learning and memory. Along with the 11.5 Neurotransmitters 413 endocrine system, the nervous system regulates many aspects of homeostasis, including 11.6 Functional Groups respiratory rate, blood pressure, body temperature, the sleep/wake cycle, and blood pH. of Neurons 417 In this chapter we introduce the multitasking nervous system and its basic functions and divisions. We then examine the structure and physiology of the main tissue of the nervous system: nervous tissue. As you read, notice that many of the same principles you discovered in the muscle tissue chapter (see Chapter 10) apply here as well. MODULE 11.1 Overview of the Nervous System Learning Outcomes 1. Describe the major functions of the nervous system. 2. Describe the structures and basic functions of each organ of the central and peripheral nervous systems. 3. Explain the major differences between the two functional divisions of the peripheral nervous system. -
The “Road Map”
PRACTICAL ROADMAP NERVOUS TISSUE DR N GRAVETT NEURONS • MOTOR • SENSORY Anterior (ventral) horn Dorsal root of spinal of spinal cord cord Multipolar Pseudounipolar ANTERIOR HORN CELLS • Slide 64 Spinal Cord (vervet monkey) Stain: Kluver and Berrera Technique NOTE: with this technique, myelin stains dark blue and basophilic substances such as rER and nuclei stain violet. In this case we use “blue” and “purple” to describe the staining and not eosinophilic and basophilic. SPINAL CORD Anterior Ventral Horn Arachnoid Ventricle Pia Mater Grey Matter White Matter Posterior Horn Dura Mater Dorsal ANTERIOR HORN CELL Neuropil Cell Body Dendrite Vesicular Nucleus Nucleolus Nucleus of Nissl Bodies Neuroglial Cell ANTERIOR HORN CELL Neuropil Cell Body Vesicular Nucleus Nucleolus Nissl Body Nucleus of Neuroglial Cell Dendrite Nissl Body Axon Hillock Axon SPINAL (DORSAL ROOT) GANGLION CELLS • Slide 62 Spinal Ganglion Stain: H&E NOTE: The spinal ganglion is also known as the dorsal root ganglia and contains pseudounipolar neuron cell bodies. SPINAL (DORSAL ROOT) GANGLIA Cell Bodies Processes (Axons and Dendrites) SPINAL (DORSAL ROOT) GANGLIA Cell Bodies Processes (Axons and Dendrites) NOTE: The neuronal cell bodies of the dorsal root ganglia are “clumped” together, and one cannot see any processes entering or leaving the cell bodies. The processes (axons and dendrites) are seen towards the edge/periphery of the group of cell bodies. SPINAL (DORSAL ROOT) GANGLIA Satellite cells (arranged in ring like fashion around the cell body) Cell Body Nucleolus Vesicular Fine Granular Nucleus Nissl Substance Nucleus of Satellite cell PERIPHERAL BRANCH OF A SPINAL NERVE • Slide 32 Median Nerve Stain: Mallory’s Technique NOTE: Three dyes are used in Mallory’s technique, which results in collagen fibres (such as connective tissue) staining blue, the “neurokeratin” staining red, and nuclei staining reddish-orange PERIPHERAL NERVE Myelinated Axons Vein L.S.