The Nervous System

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THE NERVOUS SYSTEM Lab Objectives Students should be able to: 1. Identify the microscopic structures of the neuron using a slide and model of a neuron. 2. Identify the microscopic and macroscopic anatomy of the spinal cord. 3. Identify the microscopic anatomy of a nerve. 4. Identify various anatomical structures on whole and sagittal section brain models. 5. Identify various anatomical structures on preserved sheep brain. I. Neuron, Neural Tissue, and Nerve(s) Motor Neuron Using the slides labeled "Motor Neuron", learn to recognize the following: 1. neuroglia cells 2. multipolar neuron a. cell body (soma) b. nucleus c. nerve cell processes Peripheral Nerve Using the slide labeled "Peripheral Nerve, c.s", learn to recognize the following: 1. Epineurium 2. Perineurium 3. Fascicles, and 4. Endoneurium (not identified in picture to the right, only seen on high power) Motor Neuron Model 1. Endoneurium 7. Telodendria (axon terminals) 2. Node of Ranvier 8. Dendrites 3. Neurilemma 9. Nucleus 4. Myelin sheaths of Schwann cell 10. Endoplasmic reticulum 5. Axon 11. Mitochondria 6. Axon hillock II. Gross Anatomy Spinal Cord (X Section) 1. Grey Matter 2. White Matter 3. Dorsal root (sensory) 4. Dorsal root ganglia 5. Ventral root (motor) 6. Posterior median sulcus 7. Posterior horn of grey matter 8. Lateral horn of grey matter 9. Anterior horn of grey matter 10. Anterior median fissue 11. Central canal Spinal Cord (longitudinal) 1. Olfactory nerve 2. Optic nerves (optic chiasma) 3. Pons 4. Medulla 5. Cervical plexus 6. Brachial plexus 7. External internal costal nerves 8. Spinal cord 9. Sympathetic chain ganglia Spinal Cord (Longitudinal ctd.) 1. Lumbar plexus 2. Sacral plexus 3. Conus medularis 4. Filum terminale 5. Cauda equina 6. Distal portion of cauda equina (leading to sacral plexus) 7. Sciatic nerve Peripheral Nerves 1. Dorsal digital 2. Spinal cord 3. Sympathetic chain ganglia 4. Supraclavicular 5. Axillary 6. Radial 7. Median 8. Ulnar 9. Palmar digital Peripheral Nerves 1. Femoral 2. Sciatic 3. Obturator 4. Saphaneous 5. Tibial 6. Sural .

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Cells of the Nervous System: the “Typical” Neuron Multipolar Neuron
2/1/2010 Book Fig. 1.1 The “Typical” Neuron Cells of the Nervous System: Neurons: cells that receive & send messages Glia: cells which support neuron functioning in many ways But Neurons Come in Many Shapes and Multipolar Neuron Sizes Types of Neurons Book Fig 1.1 Sensory Neuron Motor Neuron Some proteins serve as receptor sites. 1 2/1/2010 Best Known Neurotransmitters (study handout linked to syllabus) • Acetylcholine (ACh) • Norepinephrine (NE) • Dopamine (DA) • Serotonin or 5-Hydroxytryptamine (5HT) • GABA Released neurotransmitter must bind to specially shaped receptors like a key fitting into a lock. We now know there are multiple subtypes of receptors for each • Glutamate-most widespread excitatory neurotransmitter. transmitter Then the transmitter must be removed from the synapse either by reuptake or enzymatic breakdown. Here’s some background on ACh before we cover an Best Known Neurotransmitters Example of a neurotransmitter related disorder (FYI only – not completely up-to-date list of the number Acetylcholine (ACh) of identified receptor subtypes) • Acetylcholine (ACh) (7 receptor subtypes) • neurons using ACh are known as “cholinergic neurons”. • Examples: Norepinephrine (NE) (11 receptor subtypes) • motor neurons • Dopamine DA) (5 receptor subtypes) • parasympathetic neurons • many CNS neurons (in cortex, basal ganglia, hippocampus, • Serotonin (5HT) (14 receptor subtypes) brainstem) • GABA (2 receptor subtypes) • Different ACh receptor types on muscle (nicotinic) than in the nervous system (muscarinic) • Glutamate (10 receptor
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NERVOUS SYSTEM : LEC / 8 Physiology of Nerves and Muscles the Nervous System Is One of the Most Complicated System of the Body in Both Structure and Function
Medical physiology Lecturer Second Stage Hiba Hazim Saleh NERVOUS SYSTEM : LEC / 8 Physiology of nerves and muscles The nervous system is one of the most complicated system of the body in both structure and function. It senses physical and chemical changes in the internal and external environment, processes them, and then responds to maintain homeostasis. Voluntary activities, such as walking and talking, and involuntary activities, such as digestion and circulation, are coordinates, regulated, and integrated by the nervous system. The entire neural network of the body relies on the transmission of nervous impulses. Nervous impulses are electrochemical stimuli that travel from cell to cell as they send information from one area of the body to another. The speed at which this occurs is almost instantaneous, thus providing an immediate response change. (Figure -1. ) Muscles Muscle tissue is composed of contractile cells or fibers that provide movement of an organ or body part. Muscles contribute to posture, produce body heat, and act as a protective covering for internal organs. Muscles make up the bulk of the body. They have the ability to be excited by a stimulus, contract, relax, and return to their original size and shape. Whether muscles are attached to bones or to internal organs and blood vessels, their primary responsibility is movement. Apparent motion provided by muscles include walking and talking. Less apparent motion include the passage and elimination of food through the digestive system, propulsion of blood through the arteries, and contraction of the bladder to eliminate urine. (Figure -2 .) Figure -1 Figure-2 Never Cell (Neuron): Nerve Cell: Is a basic unit of nervous system.
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Nerve Cell Impulses
• Localization of Certain Neurons Neurotransmitters Nerve Conduction by: Mary V. Andrianopoulos, Ph.D Clarification: Types of Neuron • There may be none, one, or many dendrites composing part of a neuron. • No dendrite = a unipolar neuron • One dendrite = bipolar neuron • More than one dendrite = multipolar neuron. Multipolar neuron Bipolar neuron Unipolar neuron Localization of Neuron types • Unipolar: – found in most of body's sensory neurons – dendrites are the exposed branches connected to receptors – axon carries the action potential in to the CNS – Examples: posterior root ganglia + cranial nerves – Usually: have peripheral + central connections Localization of Neuron types • Bipolar: – retina, sensory cochlear, vestibular ganglion • Multipolar: (fibers) brain + spinal cord – found as motor neurons and interneurons – neuronal tractsÆ CNS – peripheral nervesÆ PNS Size of Neurons + their localization • Golgi I: – Fiber tracts: brain + spinal cord (PNS + motor) – (i.e., Pyramidal tract + Purkinje cells) • Golgi II: – Cerebral + cerebellar cortex – Often inhibitory – Out number Golgi I – Star-shaped appearance 2° short dendrites Histology of the Nervous System A review of Cell types 1) Neurons - the functional cells of the nervous system 2) Neuroglia (glial cells) - Long described as supporting cells of the nervous system, there is also a functional interdependence of neuroglial cells and neurons a) astrocytes - anchor neurons to blood vessels, regulate the micro-environment of neurons, and regulate transport of nutrients and wastes to and from neurons b) microglia- are phagocytic to defend against pathogens and monitor the condition of neurons c) ependymal - line the fluid-filled cavities of the brain and spinal column and play a role in production, transport, and circulation of the CSF.
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The Nervous System 1) Integration of Body Processes 2) Control of Voluntary Effectors (Skeletal Muscles), and Mediation of Voluntary Reflexes
1 © Jim Swan These slides are from class presentations, reformatted for static viewing. The content contained in these pages is also in the Class Notes pages in a narrative format. Best screen resolution for viewing is 1024 x 768. To change resolution click on start, then control panel, then display, then settings. If you are viewing this in Adobe Reader version 7 and are connected to the internet you will also be able to access the “enriched” links to notes and comments, as well as web pages including animations and videos. You will also be able to make your own notes and comments on the pages. Download the free reader from [Adobe.com] 1 Functions of the Nervous System 1) Integration of body processes 2) Control of voluntary effectors (skeletal muscles), and mediation of voluntary reflexes. 3) Control of involuntary effectors ( smooth muscle, cardiac muscle, glands) and mediation of autonomic reflexes (heart rate, blood pressure, glandular secretion, etc.) 4) Response to stimuli 5) Responsible for conscious thought and perception, emotions, personality, the mind. 2 These functions relate to control of the skeletal muscles discussed in Unit 2 as well as future discussion of reflexes, the brain, and the autonomic nervous system. 2 Structural Divisions of the Nervous System Central Nervous System (CNS) Brain Spinal Cord Peripheral Nervous System (PNS) nerves, ganglia, receptors 3 The central nervous system develops from the neural tube, while the peripheral nervous system develops from the neural crest cells. 3 Functional Divisions of the Nervous System 1) The Voluntary Nervous System - (a.k.a. somatic division) willful control of effectors (skeletal muscles), and conscious perception.
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Human Anatomy and Physiology I Laboratory
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Neurons and Glia
Neurons and Glia INTRODUCTION THE NEURON DOCTRINE THEGOLGI STAIN CAJAL'SCONTRTBUTTON r Box 2.I O.fSpecial Interest: Advances in Microscopy THE PROTOTYPICAL NEURON THESOMA Ihe Nucleus r Box 2.2 Brain Food:Expressing One's Mind in the Post-GenomicEra RoughEndoplosmic Reticu/um SmoothEndoplosmic Reticulum ond the GolgiApporotus The Mitochondrion THE NEURONALMEMBRANE THE CYTOSKELETON Microtubules r Box 2.) Af SpecialInterest: Alzheimer's Disease and the Neuronal Cytoskeleton Miuofiloments Neurofloments THEAXON TheAxonTerminal Ihe Synopse AxoplosmicTronsport r Box 2.4 Of SpecialInterest: Hitching a Ride With RetrogradeTtansport DENDRITES r Box 2.5 Of SpecialInterest: Mental Retardationand Dendritic Spines r Box 2.6 Pathof Discovery:Spines and the StructuralBasis of Memory, by William Greenough CLASSIFYINGNEURONS CLASSIFICATIONBASED ON THE NUMBEROF NEURITES CLASSIFICATIONBASED ON DENDRITES CLASSIFICATIONBASED ON CONNECTIONS CLASSIFICATIONBASED ON AXON LENGTH CLASSIFICATIONBASED ON NEUROTRANSMITTER GLIA ASTROCYTES MYELINATINGGLIA OTHERNON-NEURONAL CELLS CONCLUDING REMARKS 24 CHAPTER 2 . NEURONSANDGLIA V INTRODUCTION All tissuesand organsin the body consistof cells.The specializedfunctions of cellsand how they interact determinethe functions of organs.The brain is an organ-to be sure, the most sophisticatedand complex organ that nature has devised.But the basicstrategy for unraveling its function is no different from that used to investigatethe pancreasor the lung. We must begin by learninghow brain cellswork individually and then seehow they are assembledto work together.In neuroscience,there is no need to sepa- rate mind from brain; once we fully understand the individual and con- certed actionsof brain cells,we will understandthe origins of our mental abilities.The organizationof this book reflectsthis "neurophilosophy."We start with the cells of the nervous system-their structure, function, and meansof communication.In later chapters,we will explorehow thesecells are assembledinto circuits that mediate sensation,perception, movement, speech,and emotion.
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Chapter 4 Central Nervous System and Sensory Organs
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Unit :3 Nervous System By: Dr
CBCS 3RD SEM (M) PAPER 3026 UNIT :3 NERVOUS SYSTEM BY: DR. LUNA PHUKAN STRUCTURE OF A NEURON A neuron or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. It is the main component of nervous tissue in all animals except sponges and placozoa. Plants and fungi do not have nerve cells. The spelling neurone has become uncommon. Neurons are typically classified into three types based on their function. Sensory neurons respond to stimuli such as touch, sound, or light that affect the cells of the sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. A group of connected neurons is called a neural circuit. A typical neuron consists of a cell body (soma), dendrites, and a single axon. The soma is usually compact. The axon and dendrites are filaments that extrude from it. Dendrites typically branch profusely and extend a few hundred micrometers from the soma. The axon leaves the soma at a swelling called the axon hillock, and travels for as far as 1 meter in humans or more in other species. It branches but usually maintains a constant diameter. At the farthest tip of the axon's branches are axon terminals, where the neuron can transmit a signal across the synapse to another cell. Neurons may lack dendrites or have no axon.
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The Neocortex of Cetartiodactyls: I. a Comparative
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NERVOUS SYSTEM: NEURAL TISSUE in Anatomy Today Nervous System Overview • Includes All Neural Tissue in the Body • 2 Divisions 1
Human Anatomy Unit 4 NERVOUS SYSTEM: NEURAL TISSUE In Anatomy Today Nervous System Overview • Includes all neural tissue in the body • 2 divisions 1. Central (CNS) – Brain – Spinal Cord 2. Peripheral (PNS) – Cranial nerves – Spinal nerves – Sensory receptors – Communicates between the CNS and peripheral tissues Nervous System Organization Anatomical Terminology of the Nervous System Central Nervous System Peripheral Nervous System • Control center • Ganglia • Nucleus – Collection of nerve cell bodies – Gray matter – Collection of nerve cell bodies • Spinal nerves • Neural cortex – White matter – Superficial gray matter – Emerge from the spinal cord • Tracts – All mixed nerves – White matter • Cranial nerves • Columns – White matter • Pathways – Emerge from the brain – Sensory – Ascending (sensory) – Motor – Descending (motor) – Mixed Anatomical Terminology of the Nervous System Flow of Information Sensory Motor • Carries sensory information • Carries motor commands from peripheral tissues to from the CNS to peripheral the brain tissues (effectors) • Somatic Sensory • Somatic – All sensory receptors – Controls skeletal muscle throughout the body • Autonomic • Special Sensory – Controls cardiac muscle, – Vision smooth muscle, glands – Hearing – 2 divisions – Equilibrium/balance • Sympathetic – Taste – Fight or flight • Parasympathetic – Smell – Rest and digest Nervous Tissue • 2 distinct types of cells 1. Neurons • Transfer and processing information in the nervous system 2. Neuroglia • Cells that support and protect neurons Neurons Neuroglia
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Neuron Basics
Cells of Neural Tissue Neurons: basic unit of the nervous system, these cells communicate with one another and with other cells Neuroglia: regulate the environment of neurons, provide supporting framework, act as phagocytes Structure of a Neuron Motor neuron Neuron from spinal cord Components of Neuron to Know Dendrites: receive incoming signals Axon: carries outgoing signals Synaptic terminal: where axon communicates with dendrites of another cell Mitochondrion: supply ATP Nucleus: houses DNA and nucleolus Nucleolus: makes ribosomes Nissl bodies: clusters of rough ER and free ribosomes - makes gray matter gray Components of Neuron to Know, continued Axon hillock: region of neuron where an action potential may arise due -to presence of specific chemicals, -mechanical pressure, -changes in temperature, or -shifts in extracellular ion concentrations Components of Neuron to Know, continued Collaterals: branches of axon Synapse: site where one neuron communicates with another neuron Schwann cells: glial cells in the PNS that myelinate the axons of neurons Node of Ranvier: part of the neuron that is NOT myelinated, in between the Schwann cells along the axon Cell Body Functional Classification of Neurons Sensory neurons: 10 million in afferent division of PNS Two kinds of receptors: Somatic sensory receptors External Proprioreceptors Visceral receptors (internal receptors) Functional Classification of Neurons, continued Motor neurons: 500,000 of efferent division of PNS carry instructions from CNS to other tissues Effectors: peripheral targets,
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Neurohistology I: Cells and General Features
Lecture 1 Neurohistology I: Cells and General Features Overall Objectives: to understand the histological components of nervous tissue; to recognize the morphological features of neurons; and to differentiate myelinated from non-myelinated axons I. Basic Organization: A. Central Nervous System (CNS)—brain and spinal cord B. Peripheral Nervous System (PNS)—all cranial and spinal nerves and their associated roots and ganglia Functional PNS Divisions: A. Somatic Nervous System—a one neuron system that innervates (voluntary) skeletal muscle or somatosensory receptors of the skin, muscle & joints. B. Autonomic Nervous System—a two neuron visceral efferent system that innervates cardiac and smooth muscle and glands. It is involuntary and has two major subdivisions: 1) Sympathetic (thoracolumbar) 2) Parasympathetic (craniosacral) II. Histological Components: A. Supporting (non-neuronal) Cells— Glial cells provide support and protection for neurons and outnumber neurons 10:1. The CNS has three types and the PNS has one: 1. Astrocytes—star-shaped cells that play an active role in brain function by influencing the activity of neurons. They are critical for 1) recycling neurotransmitters; 2) secreting neurotrophic factors (e.g., neural growth factor) that stimulate the growth and mainte- nance of neurons; 3) dictating the number of synapses formed on neuronal surfaces and modulating synapses in adult brain; and 4) maintaining the appropriate ionic composition of extracellular fluid surrounding neurons, by absorbing excess potassium and other larger molecules. 2. Oligodendrocytes— The oligodendrocyte is the analog of the Schwann cell in the central nervous system and is responsible for forming myelin sheaths around brain and spinal cord axons. Myelin is an electrical insulator.
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