Chedy - theme 6

Question 1

Giant squid giant axons:

Answer 1

0.5mm diameter. Unmyelinated, which decreases conduction velocity. Voltmeter records voltage difference between inside/outside of neuron.

Question 2

Resting potential inside cells:

Answer 2

-70 mV. Interior is more negative.

Question 3

Membrane factors that contribute to RESTING potential:

Answer 3

Na+/K+ ATPase pump, ion channels, negatively charged ions

Question 4

Na+/K+ ATPase pump:

Answer 4

Transports 3 Na+ out and 2 Ka+ in.

Question 5

The stronger the stimulus, the stronger the response?

Answer 5

NO!

Question 6

Potassium channels : sodium channels. Significance?

Answer 6

50x more K+ than Na+. At rest, the membrane is more permeable to K+.

Question 7

Evolution of the Na+/K+ pump:

Answer 7

K+ opens one ms later than Na+. Na+ goes out really fast, then K+ comes in to fix the charge.

Question 8

Saltatory conduction of action potentials:

Answer 8

Signals travel super fast because myelination only allows charge conduction in certain places. There’s a diagram for this.

Question 9

Summation:

Answer 9

EPSPs hang out for a bit and then they add up (constructive interference). Then they calm the frick down and cancel out with IPSPs.

Question 10

Graded potentials:

Answer 10

Excitatory postsynaptic potentials and inhibitory postsynaptic potentials are summed