1. Nervous Systems Ch. 48 Ch. 48

2. Nervous System

3. Central Nervous System

4. PNS

5. Sym- pathetic Sym- pathetic Stress (like a “fight or flight” response) Stress (like a “fight or flight” response) Para- sympa- thetic Para- sympa- thetic Peace (relaxed, normal functions) Peace (relaxed, normal functions) AUTONOMIC

6. Nervous system PNS, CNS PNS, CNS INPUT: Sensory Neurons (receptors) INPUT: Sensory Neurons (receptors) INTEGRATION: CNS(brain & spinal cord) Interneurons INTEGRATION: CNS(brain & spinal cord) Interneurons OUTPUT: Motor Neurons (effectors) OUTPUT: Motor Neurons (effectors) afferent efferent interneurons Effector cells

7. The Reflex Arc

8. The Neuron Dendrites receive the signal, axon delivers the signal away to another neuron or to the CNS Dendrites receive the signal, axon delivers the signal away to another neuron or to the CNS Myelin sheaths (white matter) insulate the axon and are made by Schwanns cells or oligodendrocytes Myelin sheaths (white matter) insulate the axon and are made by Schwanns cells or oligodendrocytes What is a Node of Ranvier? What is a Node of Ranvier? What is saltatory conduction? What is saltatory conduction? What is a synapse? What is a synapse?

9. Anatomy of a Neuron >Speed of Transmission: Larger axons & Myelin sheath (Saltatory conduction) Makes myelin - PNS

10. Think! Turn to your partner and discuss… 1. Name the three types of neurons and their functions. Which make up the CNS and the PNS? 2. Describe the main parts of a neuron. 3. Describe what happens in a Reflex Arc. 4. How are Nodes of Ranvier and Saltatory conduction related? 5. What occurs at the synapse?

11. What makes a signal travel down the axon ? What makes a signal travel down the axon ?

12. 0 1 2 3 4 Time (milliseconds) Action Potential (“all or none” nerve impulse) resting state restored (-70) EPSP Threshold Potential reached: -55mV Hyperpolarization from too many K+ ions leaving Na+ Gates Open …Na+ flood cell Membrane potential (mV) - 90 -80 -70 -50 0 +35 K+ out of the cell Na/K pump restores Na+ Gates Close and K+ Open depolarization IPSP repolarization

13. Hyperpolarization: more negative inside by K + moving out—does not cause an action potential Depolarization: inside gains more positive charge by Na + rushing in INHIBITORY(-) EXCITATORY (+) What is meant by all–or–none action potential? -70

14. Think! Turn to your partner and discuss… 1. What causes an action potential? 2. What significance is the -55mV? 3. Describe the differences between depolarozation, repolarization, and hyperpolarization.

15. The steps of an action potential…

16. Na + gates closed, K + gate closed Na/K pump is maintaining –70mV Resting State

17. thres Na + gate OPENS, (fast gate) K + channels are still closed (slow gate) Na + rushes into the neuron (+ + + +) Depolarizing Phase

18. Na + inactivation gate closes, K + slow gate OPENS K + rushes out of the neuron RE-polarizing Phase

19. Na + channels closed, K + channels still OPEN K + still rushes out of the neuron (Hyperpolarizing the inside - - - - - -) Undershoot

20. Direction of transmission? Slow closing of the K+ channels prevents “back- flow” One way flow of Electricity!

21. Chemical synapses TERMS: TERMS: Vesicles Vesicles synaptic cleft synaptic cleft neurotrans- mitters neurotrans- mitters (Ca 2+ ) (Ca 2+ ) receptor receptor ion channel ion channel Pre/post synaptic membrane Pre/post synaptic membrane Enzymes to degrade the neurotrans- mitters Enzymes to degrade the neurotrans- mitters

22. Summation of IPSP & EPSP Inhibitory(-) & Excitatory(+) Post-Synaptic Potential Temporal and Spatial Summation

23. The real thing........ Cerebrum Cerebellum Brain stem: medulla oblongata, pons, midbrain Thalamus Hypothalamus

24. Cerebrum

25. Right versus left Cerebrum

26. BRAIN STRUCTURES AND FUNCTIONS Brain Stem: Brain Stem: Medulla Oblongata & Pons = (autonomic, homeostatic, data conduction) Medulla Oblongata & Pons = (autonomic, homeostatic, data conduction) Midbrain = (receives and integrates sensory information) Midbrain = (receives and integrates sensory information) Cerebellum: Automatic coordination of movements and balance Cerebellum: Automatic coordination of movements and balance Thalamus:integration of stimuli coming to the brain Thalamus:integration of stimuli coming to the brain Hypothalamus: important homeostatic regulation (temperature, hunger, thirst) & hormones Hypothalamus: important homeostatic regulation (temperature, hunger, thirst) & hormones Cerebrum: memory, learning, emotions, motor movements, sensory cortex areas Cerebrum: memory, learning, emotions, motor movements, sensory cortex areas