nerve impulse transmission objectives: 4. explain how nerve impulses are generated and how they are...
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NERVE IMPULSE TRANSMISSIONOBJECTIVES:4. Explain how nerve impulses are generated and how they are conductedalong a nerve fiber (pp. 877 – 879)5. Describe the mechanism of nerve impulse transmission at the synapse.(pp. 877 – 879)
I. Neuron at restOutside is Positively charged due to Na+ ions.
Inside is negatively charged due to Nucleic Acids and Proteins
II. When the neuron is stimulated
• NA+ rushes in and creates the “Action Potential”• The inside is now positive(Action Potential).
Action Potential
AP
III. How does the neuron reset itself?1) Reset Charge:
K+ exits neuron
Action Potential
AP
III. How does the neuron reset itself?2) Reset Ions
K+ / Na+ pump resets the ions back to normal
Action Potential
What happens:
1. Impulse reaches end bulb2. Ca2+ channels/gates open and
Ca2+ enters3. Vesicles migrate and fuse with
membrane
4. Neurotransmitter released into Synapse
5. Neurotransmitter binds to receptors on adjacent neuron, causes it to depolarizes
Transmission Across a synapse Lab
1) Obtain a microscope and slide2) On your paper, draw a picture of
your slide on 400 power.3) Find the neuron and label the
following parts on your picture:– Axon– Presynaptic neuron– Vesicles– Postsynaptic muscle
Questions
1) What causes the vesicles in the neurons end bulb to release its contents?
2) What carries the nerve impulse across the synapse?3) What is another name for a nerve impulse?
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