the nervous system: the basic structure
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The Nervous System: The Basic Structure. 6-1. From “Running and ME: A Love Story” by Joan Nesbit, 1999. - PowerPoint PPT PresentationTRANSCRIPT
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The Nervous System:The Basic Structure
6-1
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From “Running and ME: A Love Story” by Joan Nesbit, 1999
It’s almost like running is this great friend we both share…Anyway, that’s what I’d like to talk to you about…running as a friend, a companion, a lover even…in other words, the relationship of running. “WHAT!?” many of you will be saying, “I thought that I was going to learn how to improve my 10k time.” Go read Runner’s World for that. You see, I don’t view running as what I DO or who I AM, but as this thing, this force, that changes me over time….
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The Nervous System
• Controls:– emotions– movements– thinking– behavior
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The Nervous System
• Parts:– central nervous system (CNS)• brain & spinal cord
– peripheral nervous system (PNS)• Smaller parts/branches of the nerves that go to the
parts of the body
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Nervous System Protection
• All parts have protection
PART TYPE OF PROTECTION
Brain Skull & sheathing
Spinal cord Vertebrae
Peripheral nerves sheathing
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Neurons
• long, thin cells of nerve tissue on which messages travel to and from the brain
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Parts of a Neuron• Cell body– Has the nucleus– Produces energy needed for the neuron to work
• Dendrites– Short, thin fibers that stick out from the cell– Receive impulses, or messages, from other neurons and send
them to the cell body• Axon– Can be very short, or several feet long– Long fiber that carries the impulses away from the cell body to
the dendrites of another neuron
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Neuron Parts cont…
• Myelin sheath– Insulates and protects the axon for some neurons– Speeds the transmission of impulses
• Axon terminals– Branch out at the end of the axon
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nucleus
dendritesAxon terminals
Cell body
axon
Myelin sheath
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Neuron Connection
• Synapse– The gap that happens between individual nerve
cells• Impulses/messages are transmitted across the
synapse to another neuron• Neurotransmitters– The chemicals released by neurons– Determines the rate at which other neurons fire
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dendrite
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Neurotransmitters
• Excite – make the neuron transmit• Inhibit – make the neuron stop transmitting
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Neuron Activity
• Neurons are either ON or OFF• Neuron tracks:–Ascending – go up• Carry messages to the brain
–Descending – go down• Carry messages from the brain to the body
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Types of Neurons
• Afferent neurons– Sensory neurons– Send messages from the organs (including eye, nose,
ear, skin)• Efferent neurons– Motor neurons– Send signals from the brain to the glands and muscles
• Interneurons– Carry impulses between neurons in the body
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Types of Activities
• Voluntary– Lifting your hand– Running– Turning your head
• Involuntary– Heartbeat– Blood pressure– Size of the pupils
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What systems control what?
• Somatic Nervous System (SNS)– Part of peripheral nervous system– Controls voluntary actions
• Autonomic Nervous System (ANS)– Controls involuntary actions
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Autonomic Nervous System (ANS)
Parts:• Sympathetic
– Prepares the body to deal with emergencies or hard labor– Speeds up the heart to get oxygen and other nutrients to the
body– Controls how much blood goes to different parts of the body– Increases blood pressure– Suspends/stops some activities (ex: digestion)
• Parasympathetic– Saves energy– Helps the body recover from hard work– Reduces the heart rate & blood pressure