electrophysiology rig Flashcards Preview

NEUR401 > electrophysiology rig > Flashcards

Flashcards in electrophysiology rig Deck (34)
Loading flashcards...
1
Q

what are the 5 control blocks on the instrument front panel?

A

1) voltage electrode (Vm)
2) bath electrodes (Im)
3) clamp
4) commands
5) current electrode

2
Q

what’s on the instrument rear panel?

A

1) BNC connector for GAIN TELEGRAPH INPUT
2) BNC connector for Ve X 10 output
3) an alarm on/off switch
4) binding posts for circuit ground and chassis ground

3
Q

voltage meter

A

reports the membrane voltage of the cell, range of +/- 199.9mV

4
Q

voltage probe connector

A

7-pin DIN connector for attachment of the voltage probe to the instrument

5
Q

Vm offset control

A

10-turn potentiometer providing up to +/- 200mV at the voltage probe input for offset of membrane junction potentials

6
Q

Vm electrode test control

A

used to determine the internal resistance of the voltage probe (10mV/M-ohm of probe resistance)

7
Q

Vm BUZZ push button

A

facilitates penetration of the voltage electrode by producing a 1kHz square wave at the pipette tip

8
Q

Vm x10 output BNC

A

reports the membrane voltage in mV multiplied by 10

9
Q

current meter

A

reads the voltage (Ve) of the current electrode when the clamp mode selector switch is off

10
Q

current meter (clamp mode selector switch set to slow or fast)

A

current meter displays the current sensed by the bath electrode

11
Q

gain select controls allows range of gain to be set from:

A

0.01 to 100

gain selector switch = 0.1 to 10, gain multiplier = 0.1, 1, 10x

12
Q

I monitor BNC

A

current outputs at full bandwidth (10 kHz)

13
Q

I monitor filtered BNC

A

current outputs filtered at 1 kHz by an integral 4-pole Bessel filter

14
Q

clamp mode selector: off

A

the clamp amplifier is disconnected from the current electrode, voltage difference between the current electrode and the bath electrode is read on the meter in the bath electrodes block

15
Q

clamp mode selector: slow

A
  • useful for screening oocytes or when high clamp speeds are not required
  • clamp speed = 0.5ms
  • measured currents are displayed on the bath electrodes meter in uA
16
Q

clamp mode selector: fast

A
  • used for most oocyte clamping
  • clamp speed is limited by the resistance of the current electrode and the oocyte membrane capacitance
  • fast clamp speed = 350us
17
Q

gain control

A

a single turn potentiometer which varies the full bandwidth open-loop gain from 0 to 2000

18
Q

Ve offset

A

range of +/- 200mV, used to adjust the offset voltage of the current electrode

19
Q

Ve x10 output BNC

A

monitors the voltage of the current electrode (x10) when the clamp mode selector switch is off

20
Q

gain telegraph output BNC

A

provides a DC voltage indicating the gain setting of the instrument, output varies from 0.2 to 2.6 volts in 200mV steps

21
Q

model cell

A

a simple circuit that mimics the properties of recording from an actual oocyte

22
Q

follicular layer

A

connective tissue that is rich in collagen

23
Q

collagenase

A

an enzyme that will break the peptide bonds of collagen, thus releasing individual oocytes

24
Q

denuded oocytes

A

individualized oocytes

25
Q

animal pole of oocytes

A

dark pigmentation, contains the nucleus

26
Q

vegetal pole of oocytes

A

lighter pigmentation, pale yellow colour

27
Q

what defines stage VI oocytes?

A

light-coloured band separating the animal and vegetal poles

28
Q

what does it mean if oocytes are covered with blood vessels?

A

the oocytes are undergoing resorption

29
Q

stage I oocytes

A

oocytes are clear and transparent (50-300um)

30
Q

stage II oocytes

A

oocytes are white and opaque (300-450um)

31
Q

stage III oocytes

A

oocytes are lightly pigmented all over (450-600um)

32
Q

stage IV oocytes

A

oocytes are starting to have yolk protein deposited into their cytoplasm and the pigment is primarily concentrated to the upper animal hemisphere (600-1000um)

33
Q

stage V oocyte

A

oocytes are accumulating yolk and have a darker pigmented colour (1000-1100um)

34
Q

stage VI oocyte

A

oocytes are fully grown and have progesterone receptors on their plasma membrane (1100-1300um)