lecture 5

Question 1

how is potential size related to distance from synapse?

Answer 1

the further you are from the synapse, the smaller the size of the potential induced by this opening of a channel.
exception: trigger zone, and along the axon, where all-or-none AP is produced.

Question 2

components needed to understand passive electrical properties?

Answer 2

1. membrane resistance (rm):
2. membrane capacitance (cm)
3. intracellular (axial) resistance (ra): the resistance for ions or currents to flow along the length of an axon or a dendrite

Question 3

how to change the input capacitance of a given cell?

Answer 3

1. there’s very little you can do to change its capacitance
2. but you can change its surface area. bigger cells have more surface area to store charge. then input capacitance would be much larger than membrane capacitance.

Question 4

how does capacitor correlate a deformable membrane?

Answer 4

the more current you pump in, the harder you add current on the capacitor.

Question 5

what is temporal summation?

Answer 5

one or multiple inputs fired at the same times or very short interval from one another.

Question 6

what is spatial summation?

Answer 6

multiple inputs at different locations all come at the same time and cause the cell to depolarize.

Question 7

length constant lamda & time constant tau?

Answer 7

1. lamda has to do with the propagation of the signal
2. tau is more like memory (how long does the signal persist)
3. changing largely the number of ion channels that a cell express in its plasma membrane , it can greatly change both its tau and its lamda.