2. Afferent Nerves Efferent Nerves

3. cell body: cell body: central part of cell; contains the nucleus axon: axon: long slender extension from cell body; used to transmit electrical signals axon terminals: axon terminals: branching ends; receives electrical signals and releases chemical signals out of the neuron dendrites: dendrites: branches that receive chemical signals & convert them into electrical signals

4. Dendrites receive an incoming signal The signals travels along Synapse : Synapse : the gap between neurons the length of the neuron The axon terminals of the pre-synaptic cell deliver the signal to the post-synaptic cell

5. A neuron is typically at -70mV RESTING POTENTIAL

6. a positive electrical signal at +35mV ACTION POTENTIAL

7. time Voltage (mV) -70 mV RESTING POTENTIAL

8. A transport protein forces ions against their concentration gradients 3 sodium (Na + ) molecules are pushed outside the cell 2 Potassium (K + ) molecules are pushed inside the cell There is a net removal of positive ions (cations) outside the cell; inside of the cell becomes negative RESTING POTENTIAL

9. time Voltage (mV) -70 mV ACTION POTENTIAL DEPOLARIZATION the inside of the cell changes from -70mV to +35mV

10. that bind receptors on the dendrites of the post-synaptic cell axon terminals of the pre-synaptic cell through exocytosis NEUROTRANSMITTERS: NEUROTRANSMITTERS: chemical signals sent from the

11. DEPOLARIZATION The binding of neurotransmitters to the receptors of dendrites triggers the opening of a few Na + channels This causes a slightly positive charge When the charge reaches the threshold (-55mV), many voltage- controlled Na + channels open, causing a flood of positive charges All-or-None Principle

12. time Voltage (mV) -70 mV ACTION POTENTIAL REPOLARIZATION the cell returns to resting potential; often overshoots this return

13. REPOLARIZATION As Na + channels close, K + gates open. K + rushes out of the cell, returning to the cell to a -70mV resting potential

14. As the action potential reaches the axon terminal, neurotransmitters are exocytosed from the neuron and bind to receptors on the next neuron

15. https://www.youtube.com/watch?v=SdUUP2pMmQ4

16. Select one of the following neurotransmitters and be prepared to share its role with the class Acetylcholine Dopamine Norepinephrine & Epinephrine Serotonin Histamine