1. Neuron

2. How do biological processes relate to behavior?
Neurons
How do biological processes relate to behavior?

3. Neurons : the communicators of the nervous system

4. Transmitting signals
Fluids containing positively charged ions (NA+) (K+) and negatively charged ions (Cl-) are constantly passing through the cell membrane
Inactive neuron has more negative inside than outside
this creates a store of energy called resting potential

5. Transmitting signals cont.
When the cell is stimulated it lets in positively charged sodium ions.
This creates action potential
Short-lived charge
Sends information down the axon to the axon terminals

6. Transmitting signals cont.
After the action potential zooms down the axon, the channels in the membrane close.
No more sodium can get in.
They remain closed for a short amount of time and no impulses can fire
This is called the refractory period

7. ALL-OR-NONE
The neuron either fires or it doesn’t

8. The Synapse

9. Neurotransmitters Neurotransmitters cross the synaptic gap
When the action potential reaches the terminal buttons, the neurotransmitters are released.
Bind to receptor sites
Like keys
Extra neurotransmitter is returned to the cell (reuptake)

10. Transmitting signal Excitatory response (+charge) –depolarization
Action potential likely
Inhibitory response (- charge) –hyperpolarization
Action potential unlikely
If the voltage changes enough to reach threshold, the neuron will fire.

11. Sodium Potassium pump
To get ready for another action potential, Na+ needs to be pumped out and K+ needs to be pumped in.