ORGANIZATION OF THE ORGANIZATION OF THE NERVOUS SYSTEM NERVOUS SYSTEM
Feb 18, 2016
ORGANIZATION OF THE ORGANIZATION OF THE NERVOUS SYSTEMNERVOUS SYSTEM
FUNCTIONSFUNCTIONSSENSORYSENSORYMOTORMOTORCOGNITIVECOGNITIVE
ANATOMICAL ORGANIZATION of the ANATOMICAL ORGANIZATION of the NERVOUS SYSTEMNERVOUS SYSTEM
NervousSystem
CNS PNS ANS
BRAIN
SPINALCORD
CRANIALNERVES
SPINALNERVES
SYMPATHETIC
PARA-SYMPATHETIC
Central Nervous System (CNS)Central Nervous System (CNS)Unpaired, bilaterally symmetrical Unpaired, bilaterally symmetrical
structures extending along the longitudinal structures extending along the longitudinal axis of the midsagittal plane of the body.axis of the midsagittal plane of the body.
Structures arising directly from the neural Structures arising directly from the neural tube.tube.
Includes:Includes:BrainBrainSpinal cordSpinal cord
Peripheral Nervous SystemPeripheral Nervous System (PNS)(PNS)Made up of transmission pathways Made up of transmission pathways
carrying information between the CNS and carrying information between the CNS and external/internal environments.external/internal environments.
Afferent (sensory) pathways:Afferent (sensory) pathways:Carry information to the CNS.Carry information to the CNS.
Efferent (motor) pathways:Efferent (motor) pathways:Carry information from the CNS.Carry information from the CNS.
Peripheral Nervous SystemPeripheral Nervous System Includes:Includes:
Cranial nerves (12 pairs)Cranial nerves (12 pairs)Spinal nerves (31 pairs)Spinal nerves (31 pairs)
Also includes sensory receptors in skin Also includes sensory receptors in skin and wall of gut tube as well as in tendons and wall of gut tube as well as in tendons and skeletal muscles.and skeletal muscles.
Also includes motor end plates between Also includes motor end plates between motor neurons and skeletal muscle fibers.motor neurons and skeletal muscle fibers.
Autonomic Nervous SystemAutonomic Nervous SystemMay be considered a subdivision of the May be considered a subdivision of the
PNS.PNS.Entirely motor.Entirely motor. Innervates smooth muscle and glands Innervates smooth muscle and glands
(viscera)(viscera)
ANS SubdivisionsANS SubdivisionsSympathetic systemSympathetic system
(fight or flight)(fight or flight)Also called thoracolumbarAlso called thoracolumbar
Parasympathetic systemParasympathetic system(feed and breed)(feed and breed)Also called craniosacralAlso called craniosacral
Parts of a NeuronParts of a NeuronCell body:Cell body:
Trophic unitTrophic unitPerikaryonPerikaryon
Dendrites:Dendrites:Receptive unitReceptive unit
Axon:Axon:Conductive unitConductive unit
Cell BodyCell BodyThat part of a neuron that encloses That part of a neuron that encloses
the nucleus and other organelles the nucleus and other organelles necessary to maintain and repair necessary to maintain and repair neuron.neuron.
Cell Body OrganellesCell Body OrganellesNucleusNucleusGolgi apparatusGolgi apparatusRERRER
RibosomesRibosomes=Nissl substance=Nissl substance
DendritesDendritesBranches off the cell body that carry Branches off the cell body that carry
information to the cell body.information to the cell body.Usually several to many.Usually several to many.Relatively short.Relatively short.Often branched.Often branched.Have receptors for neurotransmitters.Have receptors for neurotransmitters.Conduct local potentials.Conduct local potentials.
AxonAxonThat part of the neuron that carries That part of the neuron that carries
information to another neuron or muscle information to another neuron or muscle cell.cell.
Usually relatively long.Usually relatively long.Single.Single.Conducts action potential (nerve impulse)Conducts action potential (nerve impulse)
AxonAxonEnds in short branched processes called:Ends in short branched processes called:
Telodendria:Telodendria:Give off endings called terminal boutons.Give off endings called terminal boutons.Terminal boutons contain synaptic vesicles Terminal boutons contain synaptic vesicles
of of neurotransmitters.neurotransmitters.May have collateral branches.May have collateral branches.
AxonAxonCell membrane is called the axolemma.Cell membrane is called the axolemma.
Cytoplasm is called the axoplasm.Cytoplasm is called the axoplasm.
AxonAxonContains:Contains:
MitochondriaMitochondriaNeurofilamentsNeurofilamentsNeurotubulesNeurotubules
Axonal TransportAxonal TransportAnterogradeAnterogradeRetrogradeRetrogradeSlow transportSlow transportFast transportFast transport
AxonAxonCovered by neurolemma:Covered by neurolemma:
Made up of Schwann cells.Made up of Schwann cells.Often myelinated:Often myelinated:
Myelin is formed by Schwann cells.Myelin is formed by Schwann cells.Note: axon is only part of neuron that is Note: axon is only part of neuron that is
ever myelinated.ever myelinated.
General TerminologyGeneral TerminologyNucleus:Nucleus:
Aggregation of dendrites and nerve cell Aggregation of dendrites and nerve cell bodies in the CNS.bodies in the CNS.
Ganglion:Ganglion:Aggregation of dendrites and nerve cell Aggregation of dendrites and nerve cell
bodies in the PNS.bodies in the PNS.
General TerminologyGeneral TerminologyNerve:Nerve:
Bundle of fibers (axons) in the PNS.Bundle of fibers (axons) in the PNS.Tract:Tract:
Bundle of fibers (axons) in the CNS.Bundle of fibers (axons) in the CNS.Commissure:Commissure:
Tract in the CNS that crosses from one Tract in the CNS that crosses from one side side to the other.to the other.
General TerminologyGeneral TerminologyWhite matter:White matter:
Areas of myelinated axons.Areas of myelinated axons.Gray matter:Gray matter:
Areas of unmyelinated axons, cell bodies, Areas of unmyelinated axons, cell bodies, and dendrites.and dendrites.
Functions of the CNSFunctions of the CNSRefer to p. 63 in syllabusRefer to p. 63 in syllabus
Spinal Nerve BranchesSpinal Nerve BranchesDorsal primary ramusDorsal primary ramusVentral primary ramusVentral primary ramusRamus recurrensRamus recurrensWhite ramus communicansWhite ramus communicansGray ramus communicansGray ramus communicans
Spinal Nerve BranchesSpinal Nerve BranchesParavertebral ganglionParavertebral ganglionSplanchnic nerveSplanchnic nervePrevertebral ganglion Prevertebral ganglion
Reflex ArcReflex ArcAfferent (sensory) pathways:Afferent (sensory) pathways:
Somatic.Somatic.Visceral (splanchnic).Visceral (splanchnic).
Efferent (motor) pathways:Efferent (motor) pathways:Somatic.Somatic.Visceral (splanchnic).Visceral (splanchnic).
Association neurons (interneurons).Association neurons (interneurons).
SynapseSynapseComponents:Components:
Presynaptic membrane:Presynaptic membrane:With synaptic vesicles filled with With synaptic vesicles filled with neurotransmitters.neurotransmitters.
Synaptic cleft:Synaptic cleft:Postsynaptic membrane:Postsynaptic membrane:
With receptors for neurotransmitters.With receptors for neurotransmitters.Monosynaptic pathways.Monosynaptic pathways.Polysynaptic pathways.Polysynaptic pathways.