Nervous System Chp 11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Components of the Nervous System Figure 11.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Central Nervous System (CNS) Components: brain and spinal cord Functions: receives, processes, and transfers information Peripheral Nervous System (PNS) Components: nerves outside CNS Sensory neurons: carry information toward the CNS Motor neurons: carry information away from CNS Principle Parts of Nervous System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Types of Neurons in the Nervous System Figure 11.2 Sensory Interneurons of CNS Motor
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Neurons: nerve cells, roles are in communication Cell adaptations: cell body, axon, dendrites Types: sensory, interneurons, motor neurons Neuroglial cells: cells specialized for support and protection of neurons Communication Cells of System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Myelinated Neuron- fast transmission of signal Figure 11.3
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Myelin sheath: found on Schwann cells in PNS A) Functions: Saves the neuron energy Speeds up the transmission of impulses Helps damaged or severed axons regenerate Myelin in CNS: formed by oligodendrocytes Myelin Sheath on Neuron
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. How Neurons Work: at Rest they are said to be polarized Figure 11.4
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Sodium-Potassium pump: 1.maintains Resting Potential more Na+ outside axon of neuron than inside Slight negative charge inside neuron due to negatively charged proteins in cell membrane Neurons Initiate Action Potentials
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Wave Depolarization: sodium moves into axon Repolarization: potassium diffuses out of axon Reestablishment of the resting potential: the normal activity of the sodium-potassium pump Action Potential
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. All or none concept: once a wave of depolarization started it can’t be stopped Self-propagating: electrical current reaches threshold throughout axon during spread of the action potential--wave moves down axon All or None and Self-Propagating Action Potentials
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Summary of Synaptic Transmission Figure 11.7
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Synaptic transmission Release of neurotransmitter Effects of neurotransmitter: Excitatory: depolarize postsynaptic cell Inhibitory: hyperpolarize postsynaptic cell Transfer of Information from Neuron to Target
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Nerves: carry signals to and from CNS Cranial nerves: connect directly to brain Spinal nerves: connect to spinal cord Sensory neurons: provide information to CNS Peripheral Nervous System: Relay Information between Tissues and CNS
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Somatic division Functions: Voluntary: conscious control of skeletal muscles Involuntary: spinal reflexes; flexor (withdrawal), crossed extensor, stretch Motor Neuron Divisions of PNS
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Autonomic division: controls automatic body functions Sympathetic division Origin: thoracic or lumbar regions Function: releases norepinephrine for fight or flight reaction; opposes parasympathetic division Motor Neuron Divisions of PNS
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Parasympathetic division Origin: brain or sacral region Function: releases acetylcholine to relax the body; opposes sympathetic division Motor Neuron Divisions of PNS
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. CNS protection Bone: skull and vertebrae Meninges Cerebrospinal fluid Blood-brain barrier: carries nutrients and waste for CNS Spinal cord: relays information through nerve tracts in white matter Central Nervous System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. 1.Hindbrain: coordinates basic, automatic, vital functions 2. Medulla oblongata: controls automatic functions of internal organs 3. Cerebellum: coordinates basic movements 4. Pons: aids flow of information 5. Midbrain: coordinates muscles related to vision & hearing Brain: 5 Major Divisions
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. 1.Forebrain: receives and integrates information concerning emotions and conscious thought 2. Hypothalamus: helps regulate homeostasis 3. Thalamus: receiving, processing, and transfer center 4. Limbic system: neuronal pathways involved in emotions and memory 5. Cerebrum/cerebral cortex: higher functions Brain: Processes & Acts on Information
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Limbic System: Emotions of Fear, Anger, Sorrow, Love Figure 11.18
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Sleep center: Stages: based on electroencephalograms (EEGs) Stage 1: transitional, random small waves on EEG Stage 2: skeletal muscles relax, little eye or body movement, EEG shows sleep spindles Sleep
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Stage 3: heart and respiration slower, EEG shows slow wave sleep Stage 4: difficult to awaken, heart and respiration slowest, body temperature decreased REM (rapid eye movement) Sleep: dreaming, EEG same as awake Sleep
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Short term: working memory, information from previous few hours Long term: information from previous days to years Memory: Storing and Retrieving Information
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Trauma: concussion, spinal cord injuries Infections: encephalitis, meningitis, rabies Neural and synaptic transmission: epilepsy, Parkinson’s disease, Alzheimer’s disease Brain tumors Disorders of the Nervous System