Chapter 2

Question 1

How do neurons generate electrical signals (electrical potentials) across the membrane?

Answer 1

There are positive charges outside the membrane and negative charges inside the membrane.

Question 2

How do neurons produce electrical signals across the membrane?

Answer 2

Due to the selective permeability of the membrane, there are specific proteins that help move ions into and out of the cell. This creates a difference in concentrations of specific ions. These proteins are active transporters and ion channels.

Question 3

What are the differences between active transporters and ion channels?

Answer 3

Active transporters use ATP to move ions against their concentration gradient into and out of the membrane. Ion channels have specific ions go down their gradient and doesn’t require ATP.

Question 4

What is the general term for the measurement of electrical signals in neurons?

Answer 4

Electrophysiological recording.

Question 5

What are the two types of electrophysiological recording?

Answer 5

Extracellular recording which places the electrode near the neuron and measures for temporal spikes. Intracellular recording places the electrode inside the neuron and measures for smaller graded changes of electrical potentials.

Question 6

What does intracellular recording specifically detect?

Answer 6

RMP, receptor potential, synaptic potential, wave form of a single action potential.

Question 7

Define RMP and the ionic basis underlying it.

Answer 7

At rest, RMP or Resting membrane potential has a negative potential at -70 mV that has a range between -40 –> -90 mV.

Question 8

Define Hyperpolarization

Answer 8

The membrane potential becomes more negative. This is to ensure that another AP won’t instantly go off.

Question 9

Define Depolarization

Answer 9

Makes the membrane potential more positive than the resting potential. This encourages more AP’s.

Question 10

Define Threshold Potential

Answer 10

This potential is the potential that must be met if an AP wants to go off. This value is -50 –> -55 mV.

Question 11

Define Electrochemical Equilibrium

Answer 11

Balance between chemical force (caused by the chemical concentration gradient of K+ moving from inside to outside of the cell) and electrical force (an opposing electrical potential) that stops K from moving across the membrane.

Question 12

What is equilibrium potential and how to calculate it.

Answer 12

The electrical potential generated across the membrane at electrochemical equilibrium. When this potential is met, there is no movement of ions.

Question 13

What are the Nernst and Goldman equation?

Answer 13

Nernst equation can be used to calculate the equilibrium potential in correspondence to the concentration gradient. The Goldman equation can be used to solve for the potential when the membrane is permeable to several different ions.

Question 14

When should you use the Nernst equation? Goldman?

Answer 14

Nernst is used for solving for the equilibrium potential in relation to one ion going against its concentration gradient while the Goldman is used for multiple ions going against their concentration gradient; when the membrane is permeable to several different ions.

Question 15

There are more _____ outside the cell and more ____ inside the cell.

Answer 15

Na^+ (positive), K^+ (negative)

Question 16

What is the ionic basis of action potentials?

Answer 16

RMP is mostly negative at -70 mV and due to membrane permeability the ion channels open and decrease their concentration gradients, making the value more positive and allowing for an AP to go off.