© 2010 Delmar, Cengage Learning 1 PowerPoint Presentation to Accompany

© 2010 Delmar, Cengage Learning 2 Chapter 10 The Nervous System Introduction, Spinal Cord and Spinal Nerves

© 2010 Delmar, Cengage Learning 3 Introduction Control center and communication network –Directs functions of body’s organs and systems –Interprets external environment –Determines reaction to change

© 2010 Delmar, Cengage Learning 4 Introduction (cont’d.) Homeostasis: balanced internal environment –Controlled by nervous and endocrine systems

© 2010 Delmar, Cengage Learning 5 5 Organization

© 2010 Delmar, Cengage Learning 6 Organization (cont’d.) Central nervous system: brain and spinal cord Peripheral nervous system –Afferent peripheral system Sensory neurons –Efferent peripheral system Somatic Autonomic - sympathetic and parasympathetic

© 2010 Delmar, Cengage Learning 7 Organization (cont’d.)

© 2010 Delmar, Cengage Learning 8 8 Classification of Nerve Cells

© 2010 Delmar, Cengage Learning 9 Neuroglia Cells Astrocytes: support, connection, blood brain barrier Oligodendroglia: support, myelin sheath formation Microglial: phagocytosis Ependymal: line the ventricles of the brain Schwann: myelin sheaths in peripheral nervous system

© 2010 Delmar, Cengage Learning 10 The Structure of a Neuron Cell body Dendrites: receptive areas Axon: extension of cell body –Schwann cells –Nodes of Ranvier

© 2010 Delmar, Cengage Learning 11 The Structure of a Neuron (cont’d.)

© 2010 Delmar, Cengage Learning 12 The Structure of a Neuron (cont’d.) Multipolar: several dendrites coming off cell body Bipolar: one dendrite and one axon Unipolar: one process extending from cell body

© 2010 Delmar, Cengage Learning 13 The Structure of a Neuron (cont’d.) Receptors: detect environmental stimuli Sensory: receive impulse from receptor site Internuncial: transmit impulse for interpretation and processing Motor: reaction to the stimulus

© 2010 Delmar, Cengage Learning 14 © 2010 Delmar, Cengage Learning 14 The Physiology of the Nerve Impulse

© 2010 Delmar, Cengage Learning 15 The Physiology of the Nerve Impulse (cont’d.) Nerve cell fiber resting potential –Na + concentration higher on outside –K + concentration higher on inside –Negative charge on inside –Positive charge on outside

© 2010 Delmar, Cengage Learning 16 The Physiology of the Nerve Impulse (cont’d.) Depolarization: Na + rush inside cell Repolarization: K + rush out to restore balance Depolarization: Repolarization moves in one direction Myelinated vs. unmyelinated All-or-none law

© 2010 Delmar, Cengage Learning 17 © 2010 Delmar, Cengage Learning 17 The Synaptic Transmission

© 2010 Delmar, Cengage Learning 18 The Synaptic Transmission (cont’d.) Synapse: axon terminal branches close to next dendrites Impulse reaches axon terminals Triggers neurotransmitter release into synaptic cleft

© 2010 Delmar, Cengage Learning 19 The Synaptic Transmission (cont’d.) Neurotransmitters –Acetylcholine Most common –Epinephrine –Norepinephrine –Serotonin –Dopamine –Endorphins

© 2010 Delmar, Cengage Learning 20 Animation – Firing of Neurotransmitters This animation illustrates the physiology of the nerve impulse [Insert FiringofNeurotransmitters.swf]

© 2010 Delmar, Cengage Learning 21 © 2010 Delmar, Cengage Learning 21 The Reflex Arc

© 2010 Delmar, Cengage Learning 22 The Reflex Arc (cont’d.) Knee-jerk reflex Maintain homeostasis –Heartbeat/breathing rates –Digestion –Coughing –Sneezing –Swallowing –Vomiting

© 2010 Delmar, Cengage Learning 23 The Reflex Arc (cont’d.) Involuntary reaction to external stimulus

© 2010 Delmar, Cengage Learning 24 © 2010 Delmar, Cengage Learning 24 Grouping of Neural Tissue

© 2010 Delmar, Cengage Learning 25 Grouping of Neural Tissue (cont’d.) White matter –Groups of myelinated axons –Forms nerve tracts in CNS Gray matter –Nerve cell bodies and dendrites –Unmyelinated axon bundles –Cortex: gray matter on surface of brain

© 2010 Delmar, Cengage Learning 26 Grouping of Neural Tissue (cont’d.) Nerve: bundle of fibers outside CNS Ganglia: nerve cell bodies outside CNS Tract: bundle of fibers inside CNS Nucleus: nerve cell bodies and dendrites inside CNS Horns: areas of gray matter in spinal cord

© 2010 Delmar, Cengage Learning 27 © 2010 Delmar, Cengage Learning 27 The Spinal Cord

© 2010 Delmar, Cengage Learning 28 Introduction Continuation of medulla oblongata 31 segments each with pair of spinal nerves Protected by meninges –Dura mater –Arachnoid –Pia mater

© 2010 Delmar, Cengage Learning 29

© 2010 Delmar, Cengage Learning 30 Functions of the Spinal Cord Conveys sensory impulses to the brain Integrates reflexes Spinal nerves connect at roots –Dorsal root: sensory –Ventral root: motor

© 2010 Delmar, Cengage Learning 31 © 2010 Delmar, Cengage Learning 31 The Spinal Nerves

© 2010 Delmar, Cengage Learning 32 The Spinal Nerves (cont’d.) All 31 pairs arise from union of dorsal and ventral roots Mixed nerves consisting of motor and sensory fibers Most exit vertebral column between vertebrae

© 2010 Delmar, Cengage Learning 33 The Spinal Nerves (cont’d.) Named and numbered according to region and level of spinal cord –Cervical: 8 pairs –Thoracic: 12 pairs –Lumbar: 5 pairs –Sacral: 5 pairs –Coccygeal: 1 pair

© 2010 Delmar, Cengage Learning 34 Summary Named the major division of the nervous system Classified neurons and neuroglial cells Discussed the physiology of the nerve impulse and transmission at synapses Named the different types of neural tissue Discussed the structure of the spinal cord Named the spinal nerves