Topic: The Nervous System Aim: What is the function of the nervous system? Do Now: Make a K-W-L Chart. Fill in the first two columns. What I Know (K) What

Topic: The Nervous Topic: The Nervous SystemSystem

AimAim: What is the function of the nervous : What is the function of the nervous system?system?

Do NowDo Now: Make a K-W-L Chart. Fill in the : Make a K-W-L Chart. Fill in the first two columns.first two columns.

What I Know (K)What I Know (K) What I Want to What I Want to Know (W)Know (W)

What I Learned What I Learned (L)(L)

What is the function of the What is the function of the Nervous System?Nervous System?

1.1. Receive and send information about Receive and send information about activities within the bodyactivities within the body

2.2. Monitor and respond to changes in the Monitor and respond to changes in the environmentenvironment

• Changes in the environment that Changes in the environment that cause a response are called cause a response are called STIMULISTIMULI (STIMULUS – singular)(STIMULUS – singular)

3.3. Nervous system tells other parts of the Nervous system tells other parts of the body what to dobody what to do

4.4. Interpret (make sense of) various Interpret (make sense of) various informationinformation

What is the stimulus? What is What is the stimulus? What is the response?the response?

1. An insect flies toward your eye and you blink An insect flies toward your eye and you blink to avoid danger.to avoid danger.

• Flying insect = stimulusFlying insect = stimulus• Blinking = responseBlinking = response2.2. You put your hand on a hot stove and You put your hand on a hot stove and

quickly remove it.quickly remove it.• Hot stove (heat) = stimulusHot stove (heat) = stimulus• Removing your hand from the stove = Removing your hand from the stove =

responseresponse3.3. A child runs into the street while you’re A child runs into the street while you’re

driving a car, and you slam on the brakes.driving a car, and you slam on the brakes.• Child running in the street = stimulusChild running in the street = stimulus• Slamming on the brakes = responseSlamming on the brakes = response

What controls a response?What controls a response?

• Responses are a result of nerve Responses are a result of nerve impulsesimpulses

• An An IMPULSEIMPULSE is a message sent by a is a message sent by a neuron (nerve cell)neuron (nerve cell)

• Responses to stimuli can be both Responses to stimuli can be both voluntary or involuntaryvoluntary or involuntary


AimAim: What is a neuron?: What is a neuron?

Do NowDo Now: Identify the stimulus and : Identify the stimulus and response in the following scenario: You’re response in the following scenario: You’re sleeping. The alarm clock buzzes and you sleeping. The alarm clock buzzes and you

awaken.awaken.

What structures are part of the What structures are part of the nervous system?nervous system?

1. Neurons: nerve cellsNeurons: nerve cells2.2. Spinal cordSpinal cord3.3. BrainBrain


AimAim: What is a reflex arc?: What is a reflex arc?

Do NowDo Now: Draw and label a neuron.: Draw and label a neuron.


AimAim: What is a reflex arc?: What is a reflex arc?

Do NowDo Now: Give an example of a receptor. : Give an example of a receptor.

Describe a Neuron.Describe a Neuron.

• Neurons can never be replacedNeurons can never be replaced• Neurons contain:Neurons contain:Cell body (1)Cell body (1)Dendrites (2)Dendrites (2)Nucleus (3)Nucleus (3)Axon (4)Axon (4)Axon terminals (5)Axon terminals (5)

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A NeuronA Neuron

Cell bodyCell body: largest part of : largest part of the neuron; contains the the neuron; contains the nucleus.nucleus.

NucleusNucleus: : control control centercenter

DendritesDendrites: branches at the : branches at the beginning of a neuron; beginning of a neuron; RECEIVERECEIVE IMPULSESIMPULSES and carry messages and carry messages TOTO the cell body the cell body

AxonAxon: long tail-like fiber; Carries : long tail-like fiber; Carries IMPULSESIMPULSES (messages) (messages) AWAYAWAY from from cell body to the end of the neuroncell body to the end of the neuron

Axon TerminalsAxon Terminals: : branches at the end of branches at the end of the neuron that pass the neuron that pass IMPULSESIMPULSES (messages) (messages) onon to dendrites of other to dendrites of other neuronsneurons

How many different types of How many different types of neurons are in the body?neurons are in the body?

• Three different types:Three different types:– Sensory neuronsSensory neurons– InterneuronsInterneurons– Motor neuronsMotor neurons

What are receptors and What are receptors and sensory neurons?sensory neurons?

• Receptor cellsReceptor cells: receive information : receive information from surroundingsfrom surroundings

• Impulses begin at receptorsImpulses begin at receptors• Sense organs are receptorsSense organs are receptors

– EyesEyes – Nose – Nose – EarsEars – Skin– Skin– TongueTongue

• Messages travel from receptors to Messages travel from receptors to the spinal cord and brain through the spinal cord and brain through SENSORY NEURONSSENSORY NEURONS

What are interneurons?What are interneurons?

• Interneurons are found in the spinal Interneurons are found in the spinal cord and braincord and brain

• Connect sensory neurons to motor Connect sensory neurons to motor neuronsneurons

What are motor neurons?What are motor neurons?

• Carry impulses from interneurons (in Carry impulses from interneurons (in brain and spinal cord) to brain and spinal cord) to EFFECTORSEFFECTORS

• EFFECTORSEFFECTORS: muscles or glands that : muscles or glands that carry out a responsecarry out a response


AimAim: What is a synapse?: What is a synapse?

Do NowDo Now: Substitute words for numbers in : Substitute words for numbers in the following reflex arc: the following reflex arc:

Stimulus→1 →2 →3 →4 →5 →ResponseStimulus→1 →2 →3 →4 →5 →Response

Describe the path of a nerve Describe the path of a nerve impulse.impulse.

• Reflex arcReflex arc = path of an impulse = path of an impulse• stimulus → receptor → sensory stimulus → receptor → sensory

neuron → interneuron → motor neuron → interneuron → motor neuron → effector → responseneuron → effector → response

interneuron

A reflex arcA reflex arc

How does an impulse get from How does an impulse get from one neuron to another neuron?one neuron to another neuron?

• Impulses travel from one neuron to Impulses travel from one neuron to another neuron in the form of an another neuron in the form of an ELECTRICAL and CHEMICAL ELECTRICAL and CHEMICAL SIGNALSIGNAL

• Electrical impulses enter neurons at Electrical impulses enter neurons at the dendrites, to cell body, through the dendrites, to cell body, through the axons, and out the end of the axon the axons, and out the end of the axon terminalterminal

What is a Synapse?What is a Synapse?

• Tiny gap between two neuronsTiny gap between two neurons

• Nerve impulse “jumps” the gap Nerve impulse “jumps” the gap (synapse) between two neurons with (synapse) between two neurons with a CHEMICAL SIGNALa CHEMICAL SIGNAL

• Chemical signal called a Chemical signal called a NEUROTRANSMITTERNEUROTRANSMITTER carries the carries the impulse from one neuron to anotherimpulse from one neuron to another

Topic: The nervous Topic: The nervous systemsystem

AIMAIM: What are the two divisions of the : What are the two divisions of the nervous system?nervous system?

Do NowDo Now: :

1. Messages (impulses) are sent in the 1. Messages (impulses) are sent in the form of __________ and ___________ form of __________ and ___________

signals across neurons.signals across neurons.• Describe the path of an impulse along Describe the path of an impulse along

one neuron.one neuron.


AIMAIM: What are the two divisions of : What are the two divisions of the nervous system?the nervous system?

Do NowDo Now: : Describe the path of an impulse Describe the path of an impulse

along one neuron.along one neuron.

How many divisions does the How many divisions does the nervous system have?nervous system have?

• Two divisions:Two divisions:– Central nervous systemCentral nervous system– Peripheral nervous systemPeripheral nervous system

• Central nervous systemCentral nervous system is the control is the control center of the body. It contains the center of the body. It contains the SPINAL CORD AND BRAINSPINAL CORD AND BRAIN

• Peripheral nervous systemPeripheral nervous system is a is a NETWORK OF NERVESNETWORK OF NERVES that branch that branch out from the central nervous system out from the central nervous system to the organs of your bodyto the organs of your body


AimAim: What are the three parts of the : What are the three parts of the brain?brain?

Do NowDo Now: Starting from the stimulus and : Starting from the stimulus and ending with a response, describe the ending with a response, describe the

reflex arc in yesterday’s lab.reflex arc in yesterday’s lab.

The central nervous systemThe central nervous systemDescribe the brain.Describe the brain.

• The brain consists of three areas:The brain consists of three areas:– CerebrumCerebrum– CerebellumCerebellum– MedullaMedulla

cerebrumcerebrum

medullamedulla cerebellucerebellumm

Describe the cerebrum.Describe the cerebrum.

• Cerebrum is the largest part of the Cerebrum is the largest part of the brain. It has wrinkled grooves and brain. It has wrinkled grooves and looks like a walnut.looks like a walnut.

• Divided into two halves (right and Divided into two halves (right and left)left)


AIMAIM: What is the peripheral nervous : What is the peripheral nervous system?system?

Do NowDo Now: What are the three parts of the : What are the three parts of the brain?brain?

What does the cerebrum What does the cerebrum control?control?

• MemoryMemory• ThinkingThinking• SpeechSpeech• The 5 sensesThe 5 senses• Emotional thoughtEmotional thought

• All voluntary All voluntary actionsactions– Ex: Walking, Ex: Walking,

running, jumpingrunning, jumping

Describe the cerebellum. What Describe the cerebellum. What does it control?does it control?

• Located under the cerebrumLocated under the cerebrum• Second largest part of brainSecond largest part of brain• Controls:Controls:

– BalanceBalance– Movement (coordination)Movement (coordination)

Describe the medulla. What Describe the medulla. What does it control?does it control?

• Located below the cerebellumLocated below the cerebellum• Connects the brain to the spinal cordConnects the brain to the spinal cord• Controls involuntary actionsControls involuntary actions

– BreathingBreathing– heartbeatheartbeat

medulla

Describe the spinal cord. What Describe the spinal cord. What does it control?does it control?

• Protected by vertebrae in the spinal Protected by vertebrae in the spinal columncolumn

• Connects the brain to the rest of the Connects the brain to the rest of the nervous systemnervous system

• Carries impulses to and from the brainCarries impulses to and from the brain• ControlsControls quick, automatic, and simple quick, automatic, and simple

responses called responses called REFLEXESREFLEXES

What is the Peripheral Nervous What is the Peripheral Nervous System?System?

• Link between the central nervous Link between the central nervous system and the rest of the bodysystem and the rest of the body

• Consists of branching nerves Consists of branching nerves throughout the bodythroughout the body

• Divided into two divisionsDivided into two divisions– AutonomicAutonomic– SomaticSomatic

How do the autonomic and How do the autonomic and somatic divisions of the somatic divisions of the

peripheral nervous system peripheral nervous system differ?differ?

• Autonomic controls involuntary Autonomic controls involuntary functionsfunctions

• Somatic controls voluntary Somatic controls voluntary

functionsfunctions

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Topic: The Nervous System Aim: What is the function of the nervous system? Do Now: Make a K-W-L Chart. Fill in the first two columns. What I Know (K) What