Transcript Document
29.2 Neurons
39 •Topic: 29.2 Nervous System and Neurons •Essential Question(s) :
1.
Draw and label a neuron on pg. 38 in picture bubble map format. and Molecules
29.2 Neurons Standard 9.d
Students know the functions of the nervous system and the role of neurons in transmitting electrochemical impulses.
Standard 9.e
Students know the roles of sensory neurons, interneurons, and motor neurons in sensation, thought, and response.
29.2 Neurons
• The nervous system is a
physically connected
network of cells , tissues, and organs • Controls thoughts, movement, and emotion
29.2 Neurons
Ex: Pupils shrinking in sunlight When you go out into the sun your nervous system senses the bright light coming into your eyes and tells your pupils to shrink and let in less light.
Try and come up with 2 more examples at your table
• • • • • • •
Senses Reflexes Heart rate Digestion Breathing rate Blinking Sneezing/coughing
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• The nervous system works
quickly
, using chemical and electrical signals.
nerves spinal chord
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– Central nervous system (CNS) includes the
brain
and
spinal cord
–interpret messages from other nerves in the body, and stores some of these messages for later use
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–Peripheral nervous system (PNS) network of
nerves that transmit messages to and from the CNS to other organs in the body
29.2 Neurons
• Like cable television • A physical wire connects your TV. to the cable provider •
Sends signals through a network of specialized tissues
29.2 Neurons SPONGE
1. Why does your body need a communication system?
2. Which system, the endocrine or the nervous, controls the rate at which you blink?
3. How might a clogged blood vessel affect the endocrine system’s ability to deliver signals?
29.2 Neurons
1. Why does your body need a communication system?
• A communication system allows the body to respond to its environment and maintain homeostasis 2. Which system, the endocrine or the nervous, controls the rate at which you blink?
• The nervous system controls the rate of blinking because it controls fast processes.
3. How might a clogged blood vessel affect the endocrine system’s ability to deliver signals?
• A clogged blood vessel might slow down the delivery of signals by the endocrine system, but not the nervous system
29.2 Neurons KEY CONCEPT The nervous system is composed of highly specialized cells.
29.2 Neurons
Neurons (aka nerve cells)are cells that can store information and send and receive messages within the nervous system. • Make up an information network (Like the internet)
Cell body Dendrites axon neurotransmitter
29.2 Neurons Neurons are highly specialized cells.
• A neuron has three parts.
1. cell body has nucleus and organelles
1 Cell body
29.2 Neurons Neurons are highly specialized cells.
• A neuron has three parts.
1. cell body has nucleus and organelles 2. dendrites receive messages from neighboring cells
2 dendrites
29.2 Neurons Neurons are highly specialized cells.
• A neuron has three parts.
1. cell body has nucleus and organelles 2. dendrites receive messages from neighboring cells 3. axon carries messages to other cells Specialized support cells- such as the myelin sheath insulate neurons’ axons and helps them send messages
3 axon
29.2 Neurons Synapse
NEURON
Synapse : Gaps between neurons
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NEURON
Neurotransmitters Neurotransmitters : Chemical signals released by neurons. Carry information from neuron to neuron.
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NEURON
Dendrites receive action potential Action Potential : Electrical impulse that carries messages
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
Dendrites of next neuron
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NEURON
Axon terminal Synapse (gap) Dendrites of next neuron Axon terminal : releases neurotransmitters (chemical signals)
29.2 Neurons Draw and label this neuron on p. 38 :
NEURON
Synapse Cell body axon Neurotransmitters Dendrites Action potential Myelin sheath Axon terminal
29.2 Neurons
• Neurons transmit information in the form of
electrical chemical
impulses and – When a neuron is stimulated, it produces an
electrical signal ( action potential )
within that neuron – Before it can move to the next cell it changes into a
chemical signal ( neurotransmitter )
– You react
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– Electrical Impulse reaches terminal.
terminal impulse
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– Electrical Impulse reaches terminal.
impulse
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– Electrical Impulse reaches terminal.
– Neurotransmitters (chemicals) release into synapse.
impulse vesicles synapse neurotransmitter receptor
29.2 Neurons
– Electrical Impulse reaches terminal.
– Neurotransmitters (chemicals) release into synapse. – Neurotransmitters stimulate next cell.
synapse impulse receptor neurotransmitter vesicles
29.2 Neurons
41 •Topic: 29.2 Types of Neurons •Essential Question(s) :
1.
Neuron Picture Tree Map on pg. 40 1.
2.
3.
4.
Function Location Real Example in story format Picture for each (should match story) and Molecules
29.2 Neurons
There are 3 types of neurons: 1) Sensory neurons 2) Interneurons 3) Motor neurons
29.2 Neurons 1. Sensory Neurons :
• The dendrites of these neurons act as
sensory receptors
• Gather information by detecting changes inside and outside of the body and sends it to the CNS •
Function
: They gather information and carry impulses into the brain and spinal cord
Outside: Light & Sound Intensities Inside: Temperature Oxygen Levels pH Levels
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29.2 Neurons
• • 1) Interneurons : Receive signals from sensory neurons and relay them
within
the brain and spinal cord Process and interpret messages 38
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• • 1) Motor neurons : Pass messages from the central nervous system to the other tissues in the body, such as muscles
Function
: Carry nerve impulses out of the brain or spinal cord to effectors • Effectors: structures that respond • ex: muscles and glands 39
29.2 Neurons Receptors Sensory Neurons Motor Neurons Effectors
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Interneurons
1 5 3 4 Spinal Cord 2 Key: Effector Motor Neuron Receptor Interneuron
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Sensory Neuron
29.2 Neurons 1 Receptor 5 Effector 3 Interneuron Spinal cord 4 motor neuron 2 Sensory neuron
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29.2 Neurons Types of Neurons Picture Tree Map Sensory Neurons Interneurons Motor Neurons
• •
Function Location
• •
Function Location
• •
Function Location Give a real life example (Tell a story) 1. The phone rings. The sensory neurons in your ear gather the sound information and send it to the CNS 2. Your brain interprets this information and identifies the sound as the phone ringing. This info is sent to the motor neurons Draw a picture for each 3. The motor neurons send nerve impulses to your muscles which allow you to answer the phone
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29.2 Neurons
In a nutshell….
•
The nervous system can:
•
Detect changes in the body
• •
Make decisions based on the info received Stimulate muscles and/or glands to respond
•
Counteract changes to maintain
homeostasis
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29.2 Neurons
Neurons (nerve cells) are cells that can store information and send and receive messages.
In a paragraph, hypothesize how drug or alcohol use might affect neurons?
29.2 Neurons How does the structure of a neuron make it effective in carrying out the functions of the nervous system?
29.2 Neurons
How does the structure of a neuron make it effective in carrying out the functions of the nervous system?
Neurons have long extensions called axons, which allow messages to be carried long distances without having to pass the signal to another cell.