Electrpchemical Impulse-note 3

Question 1

Action potentials in myelinated neurons

Answer 1

Occur at nodes of ranvier which contain voltage gated channels.
When the sodium enters it moves quickly to the next node.
Action potentials jump from nose to node = saltatory conduction

Question 2

What is the synapse?

Answer 2

Junction between two communicating neurons

To complete a signal neurotransmitter is released at the gap of the next neuron

Question 3

What are the 2 different kinds of neurotransmitters and there functions?

Answer 3

Excitatory- allow positive ions to flow into postsynaptic membrane causing depolarization

Inhibitory- allows K+ to flow out causing hyperpolarization

Question 4

Serotonin

Answer 4

Neurotransmitter that increases activity then eventually decreases activity
Drugs- ecstasy and LSD
Overstimulation of cell

Question 5

Dopamine

Answer 5

Increases activity
Drugs- meth heroine, weed, cocaine

Overstimulates cell by dopamine binding again and again

Question 6

Actions potentials

ADD GRAPH.

Answer 6

1. neuron membrane has -70mV
2. stimulus is received
3. voltage gated Na+ channels open
4. Na+ Ions diffuse inward, DEPOLARIZING the membrane +40mV
5. Na+ channels close and K+ channels open
6. K+ diffuse outward REPOLARIZING the membrane
7. Membrane becomes HYPERPOLARIZED to -90mV
8. K+ channels close
9. Na/K pump restores resting potential

NOTE: refractory period membrane cannot undergo another action safety mechanism