THE NERVOUS THE NERVOUS SYSTEMSYSTEM

HOW DOES IT WORK?HOW DOES IT WORK?

Function of the Nervous SystemFunction of the Nervous System

ControlsControls andand coordinatescoordinates functions throughout the functions throughout the bodybody

How?How? By responding to external and internalBy responding to external and internal stimulistimuli!!

List 3List 3 externalexternal ((outsideoutside the body) stimuli: the body) stimuli: TemperatureTemperature TextureTexture BrightnessBrightness

List 2List 2 internalinternal ((insideinside the body) stimuli: the body) stimuli: Heart rateHeart rate PeristalsisPeristalsis

NeuronsNeurons

Special cell that transmits impulses 3 TYPES

Sensory From sense organs (eyes, nose, skin, ears,

tongue) to brain/spinal cord Motor

From brain/spinal cord to muscles/glands Interneurons

Interconnect other two types Found in brain and spinal cord

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Parts of a NeuronParts of a Neuron

The SynapseThe Synapse• Impulses areImpulses are transmittedtransmitted from one neuron to from one neuron to

the nextthe next

• Synapse:Synapse:– TheThe spacespace betweenbetween neuronsneurons where impulseswhere impulses “ “jumpjump” ”

from one neuron to the nextfrom one neuron to the next

• Neurotransmitters:Neurotransmitters:– ChemicalsChemicals used to helpused to help transfertransfer thethe impulseimpulse across across

thethe synapsesynapse– Found inFound in tiny sacs (vesicles)tiny sacs (vesicles) at theat the axon terminalsaxon terminals– Released fromReleased from vesiclesvesicles by theby the impulseimpulse reaching thereaching the

axon terminalsaxon terminals

The SynapseThe Synapse

The Nervous SystemThe Nervous System

How is it made up?How is it made up?

Divisions of the Nervous SystemDivisions of the Nervous System

• The nervous The nervous system is divided system is divided into into 22 main parts: main parts:– The Central The Central

Nervous Nervous System (CNS)System (CNS)

– The Peripheral The Peripheral Nervous Nervous System (PNS)System (PNS)

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The Central Nervous System The Central Nervous System (CNS)(CNS)

• Consists of:Consists of:– The brainThe brain

– The spinal cordThe spinal cord

The BrainThe Brain• CerebrumCerebrum

– LargestLargest part of brainpart of brain– All All voluntaryvoluntary (you can control!) movements (you can control!) movements

controlled herecontrolled here– LeftLeft side of brain deals with right side of body side of brain deals with right side of body

andand vice versavice versa

• CerebellumCerebellum– SecondSecond largest regionlargest region– CoordinationCoordination andand balancebalance

• ““Bellum balance”Bellum balance”

The Brain con’t…..The Brain con’t…..• Brain stemBrain stem

– Connects Connects brainbrain to to spinal cordspinal cord– Consists ofConsists of

• Medulla oblongataMedulla oblongata (heart rate, etc) (heart rate, etc)

• ThalamusThalamus– Receives Receives messagesmessages from from sensesense organs organs

• HypothalamusHypothalamus– Control center for hunger, fatigue, body tempControl center for hunger, fatigue, body temp

PARTS OF THE BRAINPARTS OF THE BRAIN

Parts of the Brain Fill-InParts of the Brain Fill-In

BRAIN CONTROLBRAIN CONTROLWhat parts of the brain control what???????

The Spinal CordThe Spinal Cord

• Communication Communication linklink btw brain and btw brain and rest of rest of bodybody

• REFLEXESREFLEXES are processed here are processed here

• Can you name some Can you name some commoncommon reflexesreflexes????????????????????????

Peripheral Nervous System (PNS)• TWOTWO FUNCTIONS FUNCTIONS

– TRANSFER IMPULSES FROMTRANSFER IMPULSES FROM SENSE SENSE ORGANSORGANS CNSCNS

– TRANSFER IMPULSES FROMTRANSFER IMPULSES FROM CNSCNS MUSCLES OR GLANDSMUSCLES OR GLANDS

– Can you remember which neurons are Can you remember which neurons are involved??involved??• SensorySensory• MotorMotor

Peripheral Nervous System (PNS)Peripheral Nervous System (PNS)

• TWO PARTSTWO PARTS

– SOMATICSOMATIC NS NS

• VOLUNTARYVOLUNTARY MOVEMENTS MOVEMENTS

– AUTONOMICAUTONOMIC NS NS

• INVOLUNTARYINVOLUNTARY ACTIONS ACTIONS

–HEARTBEATHEARTBEAT

–GLAND STIMULATIONGLAND STIMULATION