EXAM 2

Question 1

electrophysiology

Answer 1

the recording of voltages between reference points in or near cell by using a probe to stimulate or measure

Question 2

How does an electrophysiology rig work?

Answer 2

An electrical signal is recorded by a microelectrode and passed along to an amplifier. The amplifier compares the recording to a ground electrode, and then passes along the signal to an oscilloscope and/or computer.

Question 3

oscilloscope

Answer 3

presents a visual display of the membrane potential over time, which can also be heard using a loudspeaker

Question 4

Why are glass pipettes necessary for patch clamp recordings?

Answer 4

because they can create tight seals

Question 5

How many electrodes are needed for any electrophysiology recording?

Answer 5

2, the recording electrode itself and a ground electrode for reference because an electrophysiology measurement is a comparison

Question 6

amplifier

Answer 6

enhances the relatively weak electrical signal from an FM antenna and receives info from the ground electrode

Question 7

Why are loudspeakers used in electrophysiology?

Answer 7

they can pick up changes in voltage over time because they can hear neurons

Question 8

Why is a vibration isolation system (air table) used?

Answer 8

to absorb tiny changes in vibration that can disturb the placement of the microelectrode

Question 9

Faraday cage

Answer 9

blocks external electrical interference to eliminate noise from sensitive electrical recording that can detect external electrical activity

Question 10

I/V curve

Answer 10

a plot of the voltage across a neuronal membrane and the associated ionic current flow through channels in the membrane

Question 11

What axis is the voltage on in the I/V curve?

Answer 11

x-axis

Question 12

What axis is the current on in the I/V curve?

Answer 12

y-axis

Question 13

How is an I/V curve produced?

Answer 13

a voltage clamp is used to hold the voltage of a neuron at a specific value and then current can be recorded using one of the patch clamp methods

Question 14

Currents with a (-) value are __.

Answer 14

inward currents; cations coming into the cell

Question 15

Currents with a (+) value are __.

Answer 15

outward currents; anions coming into the cell

Question 16

Non-voltage dependent channels are ___ channels.

Answer 16

independent

Question 17

magnification

Answer 17

how much larger the sample appears compared to its actual size

Question 18

resolution

Answer 18

the minimum distance by which two points can be separated yet still be distinguishable as two separate points

Question 19

numerical aperture

Answer 19

a measure of the light-collecting ability of the microscope objective

Question 20

What does a higher numerical aperture mean?

Answer 20

more light rays collected, leading to better resolution

Question 21

What does the numerical aperture of an objective depend on?

Answer 21

the angle that light enters the objective and the index of refraction of the medium in which the objective is working

Question 22

index of refraction (refractive index)

Answer 22

indicates changes in the speed of light traveling through a particular medium

Question 23

What does a greater index of refraction mean?

Answer 23

the greater the index of refraction, the greater the numerical aperture

Question 24

What does the slope of the tracing in an I/V curve mean?

Answer 24

it indicates the resistance of the channel (or conductance)

Question 25

What does a greater slope mean?

Answer 25

it indicates more charges per unit time passing through the channel for a given voltage