The Nervous System: The Basic Structure

1. The Nervous System:The Basic Structure 6-1

2. 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….

3. The Nervous System • Controls: • emotions • movements • thinking • behavior

4. 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

5. Nervous System Protection • All parts have protection

6. Neurons • long, thin cells of nerve tissue on which messages travel to and from the brain

7. 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

8. 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

9. dendrites Axon terminals Cell body axon Myelin sheath nucleus

10. 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

13. dendrite

14. Neurotransmitters • Excite – make the neuron transmit • Inhibit – make the neuron stop transmitting

15. 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

16. 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

17. Types of Activities • Voluntary • Lifting your hand • Running • Turning your head • Involuntary • Heartbeat • Blood pressure • Size of the pupils

18. What systems control what? • Somatic Nervous System (SNS) • Part of peripheral nervous system • Controls voluntary actions • Autonomic Nervous System (ANS) • Controls involuntary actions

19. 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