Spikes

Question 1

What is a spike?

Answer 1

A brief pulse-like electrical event involving the sudden opening of sodium channels

Question 2

What is the membrane potential inside the cell when the sodium channels open?

Answer 2

+60mV

Question 3

What do neurons do?

Answer 3

Receive, sort out and transmit electrical signals

Question 4

How is long distance communication achieved in a single neuron?

Answer 4

Spikes

Question 5

What do the dendrites and axons do in a neuron?

Answer 5

Dendrites: receive the electrical signal (chemically activated channels)

Axon: carries the signal from one end of the neuron to the other (voltage activated channels)

Question 6

What are cells called that make spikes?

Answer 6

Excitable

Question 7

How does a spike travel?

Answer 7

Propagation

Question 8

How is a spike triggered

Answer 8

Stimulus causes a local electrical signal that is strong enough to exceed the threshold

Question 9

Does spike amplitude change depending on the size of the stimulus?

Answer 9

No

Question 10

What does the speed of spike travel depend on?

Answer 10

Axon width: wide is quicker
Temperature: warmer is quicker
Myelin: insulation

Question 11

What is it called when a spike jumps from node to node?

Answer 11

Saltatory conduction

Question 12

What is the refractory period?

Answer 12

Can not produce another spike for a period of 1-2ms

Question 13

What did Hodgkin and Huxley do/find?

Answer 13

Experimented on giant axons in a squid using intracellular recordings to show the polarity reverses during a spike

Also had a theory on the sequence of events in ion channels