HRR: ionic basis of membrane potential

Question 1

What is the typical shape of glutamate neurons?

Answer 1

cortical pyrimidal

Question 2

Describe the difference between passive and active properties of membranes.

Answer 2

Passive: responses that occur under threshold; they do not propagate far in an axon, and the signal strength decreases as we move farther from the site of current

Active: depolarization that passes threshold, followed by a hyperpolarization. This is indicative of an action potential

Question 3

Describe how increased stimulus impacts action potentials

Answer 3

The number of action potentials may increase, but the degree of depolarization does not change. Action potential is all-or-nothing, so the number can be impacted but amplitude is not

Question 4

The inside of the cell is more ___ than the outside (positive vs negative)

Answer 4

negative

Question 5

List the two major factors that underlie the resting membrane potential.

Answer 5

Differences in concentration: the concentrations of various ions inside and outside the cell helps establish a resting membrane potential. We have more negative ions inside the cell, creating a more negative environment inside.

Differences in permeability: the membrane is selectively permeable, choosing what it lets into the cytoplasm. Ion channels and active transporters help control the permeability and thus control the resting membrane potential.

Question 6

What ion is considered the major control of resting membrane potential?

Answer 6

potassium

Question 7

describe leak channels

Answer 7

They impact the propagation of a signal on an axon; they are always open and allow for the movement of potassium

Question 8

what is the difference between the nerst equation and the goldman equation

Answer 8

nerst can only tell the concentration of one ion, while the goldman equation accounts for several permeant ions

Question 9

describe how the concentration gradient of potassium impacts resting membrane potential

Answer 9

a greater potassium concentration gradient causes a lower driving force of the electrical potential and an increase in membrane potential

Question 10

there is greater potassium ___ the cell

Answer 10

inside

Question 11

there is greater sodium ___ the cell

Answer 11

outside