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 I Want to Know (W) What I Learned (L)

What is the function of the Nervous System? 1.Receive and send information about activities within the body 2.Monitor and respond to changes in the environment Changes in the environment that cause a response are called STIMULI (STIMULUS – singular)Changes in the environment that cause a response are called STIMULI (STIMULUS – singular) 3.Nervous system tells other parts of the body what to do 4.Interpret (make sense of) various information

What is the stimulus? What is the response? An insect flies toward your eye and you blink to avoid danger. 1. An insect flies toward your eye and you blink to avoid danger. Flying insect = stimulusFlying insect = stimulus Blinking = responseBlinking = response 2.You put your hand on a hot stove and quickly remove it. Hot stove (heat) = stimulusHot stove (heat) = stimulus Removing your hand from the stove = responseRemoving your hand from the stove = response 3.A child runs into the street while you’re 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? Responses are a result of nerve impulsesResponses are a result of nerve impulses An IMPULSE is a message sent by a neuron (nerve cell)An IMPULSE is a message sent by a neuron (nerve cell) Responses to stimuli can be both voluntary or involuntaryResponses to stimuli can be both voluntary or involuntary

Topic: The Nervous System Aim: What is a neuron? Do Now: Identify the stimulus and response in the following scenario: You’re sleeping. The alarm clock buzzes and you awaken.

What structures are part of the nervous system? Neurons: nerve cells 1. Neurons: nerve cells 2.Spinal cord 3.Brain

Topic: The Nervous System Aim: What is a reflex arc? Do Now: Draw and label a neuron.

Topic: The Nervous System Aim: What is a reflex arc? Do Now: Give an example of a receptor.

Describe a Neuron. Neurons can never be replacedNeurons can never be replaced Neurons contain:Neurons contain:  Cell body (1)  Dendrites (2)  Nucleus (3)  Axon (4)  Axon terminals (5) 3 4 5

A Neuron Cell body: largest part of the neuron; contains the nucleus. Nucleus: control center Dendrites: branches at the beginning of a neuron; RECEIVE IMPULSES and carry messages TO the cell body Axon: long tail-like fiber; Carries IMPULSES (messages) AWAY from cell body to the end of the neuron Axon Terminals: branches at the end of the neuron that pass IMPULSES (messages) on to dendrites of other neurons

How many different types of neurons are in the body? Three different types:Three different types: –Sensory neurons –Interneurons –Motor neurons

What are receptors and sensory neurons? Receptor cells: receive information from surroundingsReceptor cells: receive information from surroundings Impulses begin at receptorsImpulses begin at receptors Sense organs are receptorsSense organs are receptors –Eyes– Nose –Ears– Skin –Tongue Messages travel from receptors to the spinal cord and brain through SENSORY NEURONSMessages travel from receptors to the spinal cord and brain through SENSORY NEURONS

What are interneurons? Interneurons are found in the spinal cord and brainInterneurons are found in the spinal cord and brain Connect sensory neurons to motor neuronsConnect sensory neurons to motor neurons

What are motor neurons? Carry impulses from interneurons (in brain and spinal cord) to EFFECTORSCarry impulses from interneurons (in brain and spinal cord) to EFFECTORS EFFECTORS: muscles or glands that carry out a responseEFFECTORS: muscles or glands that carry out a response

Topic: The Nervous System Aim: What is a synapse? Do Now: Substitute words for numbers in the following reflex arc: Stimulus → 1 → 2 → 3 → 4 → 5 → Response

Describe the path of a nerve impulse. Reflex arc = path of an impulseReflex arc = path of an impulse stimulus → receptor → sensory neuron → interneuron → motor neuron → effector → responsestimulus → receptor → sensory neuron → interneuron → motor neuron → effector → response interneuron

A reflex arc

How does an impulse get from one neuron to another neuron? Impulses travel from one neuron to another neuron in the form of an ELECTRICAL and CHEMICAL SIGNALImpulses travel from one neuron to another neuron in the form of an ELECTRICAL and CHEMICAL SIGNAL Electrical impulses enter neurons at the dendrites, to cell body, through the axons, and out the end of the axon terminalElectrical impulses enter neurons at the dendrites, to cell body, through the axons, and out the end of the axon terminal

What is a Synapse? Tiny gap between two neuronsTiny gap between two neurons Nerve impulse “jumps” the gap (synapse) between two neurons with a CHEMICAL SIGNALNerve impulse “jumps” the gap (synapse) between two neurons with a CHEMICAL SIGNAL Chemical signal called a NEUROTRANSMITTER carries the impulse from one neuron to anotherChemical signal called a NEUROTRANSMITTER carries the impulse from one neuron to another

Topic: The nervous system AIM: What are the two divisions of the nervous system? Do Now: 1. Messages (impulses) are sent in the form of __________ and ___________ signals across neurons. Describe the path of an impulse along one neuron.Describe the path of an impulse along one neuron.

Topic: The nervous system AIM: What are the two divisions of the nervous system? Do Now: Describe the path of an impulse along one neuron.

How many divisions does the nervous system have? Two divisions:Two divisions: –Central nervous system –Peripheral nervous system Central nervous system is the control center of the body. It contains the SPINAL CORD AND BRAINCentral nervous system is the control center of the body. It contains the SPINAL CORD AND BRAIN Peripheral nervous system is a NETWORK OF NERVES that branch out from the central nervous system to the organs of your bodyPeripheral nervous system is a NETWORK OF NERVES that branch out from the central nervous system to the organs of your body

Topic: The nervous system Aim: What are the three parts of the brain? Do Now: Starting from the stimulus and ending with a response, describe the reflex arc in yesterday’s lab.

The central nervous system Describe the brain. The brain consists of three areas:The brain consists of three areas: –Cerebrum –Cerebellum –Medulla cerebrum medulla cerebellum

Describe the cerebrum. Cerebrum is the largest part of the brain. It has wrinkled grooves and looks like a walnut.Cerebrum is the largest part of the brain. It has wrinkled grooves and looks like a walnut. Divided into two halves (right and left)Divided into two halves (right and left)

Topic: The nervous system AIM: What is the peripheral nervous system? Do Now: What are the three parts of the brain?

What does the cerebrum control? MemoryMemory ThinkingThinking SpeechSpeech The 5 sensesThe 5 senses Emotional thoughtEmotional thought All voluntary actionsAll voluntary actions –Ex: Walking, running, jumping

Describe the cerebellum. What does it control? Located under the cerebrumLocated under the cerebrum Second largest part of brainSecond largest part of brain Controls:Controls: –Balance –Movement (coordination)

Describe the medulla. What 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 –Breathing –heartbeat medulla

Describe the spinal cord. What does it control? Protected by vertebrae in the spinal columnProtected by vertebrae in the spinal column Connects the brain to the rest of the nervous systemConnects the brain to the rest of the nervous system Carries impulses to and from the brainCarries impulses to and from the brain Controls quick, automatic, and simple responses called REFLEXESControls quick, automatic, and simple responses called REFLEXES

What is the Peripheral Nervous System? Link between the central nervous system and the rest of the bodyLink between the central nervous system and the rest of the body Consists of branching nerves throughout the bodyConsists of branching nerves throughout the body Divided into two divisionsDivided into two divisions –Autonomic –Somatic

How do the autonomic and somatic divisions of the peripheral nervous system differ? Autonomic controls involuntary functionsAutonomic controls involuntary functions Somatic controls voluntarySomatic controls voluntaryfunctions