1. The Nervous System

2. Nervous System Network of connected cells, tissue, and organs
Controls thoughts, movement, life processes
Quick responses
Ex: Sunny day  pupils shrinking

3. CNS and PNS

4. Neurons AKA: Nerve Cells
Transfer electrical impulses to/from the brain
3 Main Parts
Cell body: contains nucleus and organelles
Dendrites: branches that receive messages from neighboring cells
Axon: extension that carries messages away from the cell body

5. Resting Potential Defined: Neuron at rest Neuron Exterior:
Positive charge
Mainly Na+ outside the cell
Neuron Interior:
Negative charge (from various proteins)
K+ inside the cell

6. Action Potential Defined: Electrical impulse is triggered
Front end of impulse
Channels open and allow Na+ to enter the cell
Negative impulse attracted towards positive Na+
Back end of impulse
Channels open to allow K+ to exit the cell
Interior returns to normal
Impulse pulled along by the changing of electrical charges

7. impulse

8. Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ K+ Na+ Na+ Na+ K+ Na+ Na+ Na+
negative impulse K+ K+ K+ K+ K+ K+ K+
Na+ K+
Na+ K+ K+ K+ K+ K+ K+
Na+ K+ K+ K+
Na+ K+ K+ K+ K+ K+ K+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+ K+
Na+
Na+
Na+ K+
Na+
Na+
Na+
Na+
Na+
Na+ K+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+ K+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+

10. Synapse Defined: Gap between neurons
Problem: Impulse cannot cross the gap
Solution: Impulse converted into chemical molecules (neurotransmitters)
Steps:
Impulse reaches neuron’s end
Vesicle releases neurotransmitters
Neurotransmitters attach to neighboring neuron
New impulse created

12. Impulse stimulates a vesicle, which contains neurotransmitters
Vesicle exits the cell and dissolves
impulse
Start of another cell
End of one cell

13. Neurotransmitters stimulate a new impulse
cross the synapse and attach to receptors of a neighboring neuron
impulse
impulse
Start of another cell
End of one cell

14. Brain …. …. …. ….
Feet

15. Motor neurons reach the muscles…
and causes MOVEMENT!

16. Kobe Kuiz What is the function of the nervous system?
List the 3 main parts and describe the purpose of the 3 main parts of a neuron.
Describe the internal and external environment of a neuron in resting potential.
What is a synapse and why is it a problem for neurons?
What are the roles of the following during an action potential?
NA+ K+
Neurotransmitters