* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Nervous System Communication
Neuroethology wikipedia , lookup
Subventricular zone wikipedia , lookup
Neuropsychology wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Action potential wikipedia , lookup
Optogenetics wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Axon guidance wikipedia , lookup
Metastability in the brain wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Electrophysiology wikipedia , lookup
Psychoneuroimmunology wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
End-plate potential wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Biological neuron model wikipedia , lookup
Node of Ranvier wikipedia , lookup
Single-unit recording wikipedia , lookup
Synaptic gating wikipedia , lookup
Circumventricular organs wikipedia , lookup
Channelrhodopsin wikipedia , lookup
Evoked potential wikipedia , lookup
Neurotransmitter wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Development of the nervous system wikipedia , lookup
Chemical synapse wikipedia , lookup
Synaptogenesis wikipedia , lookup
Neural engineering wikipedia , lookup
Microneurography wikipedia , lookup
Nervous system network models wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Nervous System Communication Kid Concussions In The News Neurons • Nerve cells • Parts of neurons – Cell body – Long extensions • Message = nerve impulse Animal Nervous Systems • Sponges – no nervous system • Other animals all have neurons in systems Nerve Net • In all cnidarians • Interconnected nerve cells • No brain Ringlike Nervous System • In echinoderms • Ring with 5 radiating nerves Ladderlike Nervous System • In many Platyhelminthes • Some have distinct brain Annelid Nervous System • Segmental ganglia – Ganglia = aggregations of nervous tissue • Ventral nerve cord & brain Vertebrate Nervous System • Central nervous system – Brain & spinal cord • Peripheral nervous system – Nerves to & from CNS Nerve Cells • Cell body – Contains nucleus – Organelles necessary for cell • Axon – Long cell extension – May have myelin covering • Dendrites – Cell extensions – No myelin covering Sensory Neurons • Receive information • Transmit to the central nervous system Motor Neurons • Transmit commands away from CNS • To muscles & glands Interneurons • Located within brain & spinal cord • Integrate information • Axons may not be myelinated Neuroglia • Nerve support cells • Provide support, protection, & nutritional stability • Schwann cells – Found around axons – Produce myelin sheath Myelin Sheath • Insulates axon • Nodes of Ranvier – Uncovered areas Nerve Impulses • Electrical signals transmitted along membranes of nerves Resting Potential • Neuron is electrically charged at rest • Outside is positively charged • Inside is negatively charged Sodium-Potassium Pump • Proteins embedded within cell membrane • Moves sodium to the outside • Moves potassium to the inside • Maintains resting potential • Requires energy Action Potential • Nerve impulse is started by a stimulus • Stimuli cause movements of ions through membrane • Threshold potential – Sufficient stimulation to depolarize membrane • Action potential – Rapid reversal of membrane electric potential Nerve Transmission • Action potential at one point depolarizes next area • Depolarization moves in self-propagating wave Saltatory Conduction • Nerve impulse jumps & moves faster along myelinated axon Synapse • Area where nerve communicates • Transfers message – Another neuron – An effector Synaptic Cleft • Neurons do not touch other neurons or effector cells • Nerve impulse must cross gap Neurotransmitters • Organic molecules (> 60 different chemicals) • Transfer message across synaptic cleft • Attach to receptors on target cell Neuromuscular Junctions • Synapse between neuron & skeletal muscle • Neurotransmitter is acytylcholine Neuron to Neuron Connections • Uses many different neurotransmitters • Some cause different effects – Excitatory synapse – continuation of impulse – Inhibitory synapse – reduce ability to depolarize Integration of Nerve Impulses • Summed impulses determine if postsynaptic neuron will depolarize Human Nervous System • Central nervous system – Brain – Spinal cord • Peripheral nervous system – Brings messages to & from CNS – Somatic nervous system – voluntary – Autonomic nervous system - involuntary Central Nervous System • Integrates sensory & motor impulses Spinal Cord • Connects peripheral nervous system with brain • Receives information via spinal nerves • Includes reflex arcs CNS Protection - Meninges • Layers of membranes – Dura mater – Arachnoid – Pia mater Peripheral Nervous System • Sensory & motor impulses • Cranial nerves communicate directly with brain Spinal Nerves • Sensory & motor nerve fibers • Travel directly to spinal cord • Nerves are bundled to form mixed nerves Motor Neuron Systems • Somatic – Voluntary – Movements of skeletal muscles • Autonomic – Involuntary – Reflex = automatic response to nerve stimulation – Involuntary motor pathways Divisions of the Autonomic Nervous System • Parasympathetic – Prevails during periods of inactivity – Housekeeping • Sympathetic – “fight or flight” – Responds to stress – Prepares body for action • Parasympathetic & sympathetic together help to maintain homeostasis Psychoactive Drugs • Affect action of nervous system – Neurotransmitters – Specific parts of the brain • Some are abused Drug Addiction • Chronic use (or abuse) of psychoactive drugs • Person becomes physically dependant • Drug use tends to increase due to drug tolerance End Chapter 32