Module 3 - Bioelectricity Flashcards

1
Q

Who is credited with the discovery of bioelectricity and when?

A

Luigi Galvani in 1700s

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2
Q

Describe galvanization

A

Galvani applied electric current to dissected frog legs, causing them to twitch

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3
Q

Describe the public experiment conducted by Giovanni Aldini (Galvani’s nephew).

A

Used body of executed prisoner
Minutes after execution, Aldini performed galvanization on the body, causing movements of the jaw, eyes, right hand and legs

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4
Q

What is electrophysiology?

A

Use of equipment to study bioelectricity

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5
Q

Who developed the differential rheotome?

A

Julius Bernstein in 1902

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6
Q

What is the differential rheotome?

A

Instrument used to sample membrane voltage in microsecond scale

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7
Q

What are the three general paradigms for electrophysiological recording?

A

Extracellular recording
Intracellular sharp electrodes
Whole-cell patch electrodes

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8
Q

What is extracellular recording?

A

Records voltage/ion fluxes along the outside surface of a cell

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9
Q

How many electrodes can be used in extracellular recording?

A

Single or multiple

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10
Q

What are intracellular sharp electrodes?

A

Record voltage/ion fluxes across the cell membrane

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11
Q

How many intracellular sharp electrodes can be used?

A

Single or double

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12
Q

What are whole-cell patch electrodes?

A

Record voltage/ion fluxes across the cell membrane

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13
Q

What is a benefit to whole-cell patch electrodes?

A

Large access into cell, allowing you to change the intracellular saline

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14
Q

What did protein engineers combine to create GCaMP calcium indicators?

A
  1. GFP
  2. The Ca2+ sensor protein calmodulin (CaM)
  3. The M13 alpha helix of the muscle protein myosin light chain kinase
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15
Q

What happens to GCaMP when Ca2+ levels rise?

A

Increases fluorescence

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16
Q

Describe how the GCaMP calcium indicator works.

A

APs cause Ca2+ influx
Ca2+ activates CaM
CaM binds the M13 helix
This pulls on the GFP protein, changing its structure
Increased GFP fluorescence

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17
Q

What is current?

A

Movement of charged particles through a conductor/resistor

18
Q

What is the symbol for current?

A

I

19
Q

What are the units for currents?

A

Amperes (A)

20
Q

What are the charged particles that move through metal wires?

A

Electrons

21
Q

What are charged particles that move through aqueous solutions?

A

Cations and anions

22
Q

What unit are charges counted/measured in?

A

Coulombs (C)

23
Q

What is the energy for charge movement?

A

Voltage

24
Q

State Ohm’s Law and define the variables

A

I = V*G
I = current
V = electrical potential energy
G = conductance

25
Q

True or false, a conductor is also a resistor?

A

True

26
Q

What is the equation that shows the relationship between resistance and conductance?

A

G = 1/R

27
Q

Outline the relationship between a conductor and a resistor.

A

A good conductor (gold) makes a bad resistance
A good resistor makes a bad conductor (rubber)

28
Q

State Ohm’s law with resistance

A

I = V/R

29
Q

What happens when a voltage is applied across a conductor/resistor?

A

A current is produced

30
Q

Where does membrane voltage originate from in excitable cells?

A

From ion concentration gradients across the cell membrane

31
Q

What are the conductors/resistors in cells?

A

Ion channels across the cell membrane

32
Q

Is the cytoplasm a conductor?

A

Yes

33
Q

Define a capacitor.

A

A capacitor consists of two conductive plates separated by an insulator

34
Q

What is the capacitor of cells?

A

Cell membrane

35
Q

What are the two conductive plates of the cell’s capacitor?

A

cytoplasmic and extracellular salines

36
Q

What is the insulator of the cell’s capacitor?

A

phospholipid bilayer

37
Q

Why must the insulator of a capacitor be thin?

A

So the charges can “sense” each other across the plates.

38
Q

What happens at a capacitor when a voltage is applied?

A

Opposite charges accumulate along opposite plates
A current results from the repulsion/attraction of ions across the membrane
Applied charge accumulate until energy in capacitor matches the applied voltage

39
Q

How are capacitors different than batteries.

A

Capacitors can hold and applied voltage and thus act as a voltage source, but cannot generate voltages, only borrow

40
Q

Give the equation for the capacitance of a capacitor and define the variables.

A

C = q/V
C = capacitance
q = charge
V = electrical potential energy

41
Q

What determines capacitance?

A

Properties of the insulator
Conductive plates
Surface area of capacitor

42
Q
A