Chapter 3: Resting Membrane Potential Flashcards

1
Q

All neurons transmit an electrochemical signal and this signal is the same in all neurons. What changes between different neurons is the —– message being released.

A

Chemical message that is released

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2
Q

What is potential in regards to the neuron membrane and how is it measured?

A

Potential is a separation of charges across the membrane and is measured in voltage ( V.)

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3
Q

Membrane potential is measured in voltage. Can you define what voltage is?

A

It is the difference in electric potential between the inside and outside of a neuron. Voltage inside the cell is measured in comparison to the outside.

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4
Q

Greater voltage means there is more or less current movement you can observe?

A

The greater the voltage, the more current movement you can see.

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5
Q

What are the names of the three electrical potentials?

A

The resting membrane potential ( RMP. Graded potentials & action potentials.

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6
Q

What are the three things necessary to measure the membrane potential of a neuron?

A

Microelectrodes, ( reference & intracellular or recording,) an amplifier, and an oscilloscope on a computer.

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7
Q

What are microelectrodes?

A

A tiny metal device used to record electrical potentials.

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8
Q

Intracellular microelectrode is placed into intra or extracellular fluid? Reference microelectrode is placed in intracellular or extracellular fluid?

A

Intracellular microelectrode is place into intracellular fluid. Reference microelectrode is placed in extracellular fluid.

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9
Q

Imagine that the voltage of a neuron is -60mV. Does this mean that the inside of the cell is more negative than the extracellular fluid or that the outside of the cells is more negative than the intracellular fluid?

A

The inside of the cell is more negative than the extracellular fluid.

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10
Q

Where is an intracellular microelectrode placed?

A

This microelectrode is placed into intracellular fluid.

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11
Q

Where is a reference microelectrode placed?

A

This microelectrode is placed in extracellular fluid.

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12
Q

The resting membrane potential is being recorded outside of the cell. When the recording electrode is outside of the cell, the difference between the reference and recording electrode is what?

A

Zero.

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13
Q

The resting membrane potential is being recorded with the recording electrode inserted into the cell membrane. Is a negative or positive potential difference seen?

A

When the recording electrode is inserted into the membrane, a negative potential difference is seen. The neuron is more negative inside relative to the outside of the cell. This is referred to as the resting membrane potential.

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14
Q

What are ions?

A

An ion is any element that contains a different number of protons and electrons. They are electrically charged particles.

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15
Q

All elemental atoms contain the same number or protons & electrons. Does this give them a positive or neutral charge?

A

This gives them a neutral charge.

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16
Q

The environment surrounding the neuronal membrane is a watery environment that contains several electrically charged particles. What are these electrically charged particles known as?

A

These are known as ions.

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17
Q

Do cations have a negative or positive charge?

A

Cations are ions that have a positive charge.

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18
Q

Do anions have a negative or positive charge?

A

Anions have a negative charge.

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19
Q

What are the five ions that surround the membrane?

A

Cations: Sodium ( Na+) , Potassium ( K+) , Calcium ( Ca2+)
Anions: Chloride ( Cl-), Negatively charged proteins ( A-)

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20
Q

How many cations surround the neuronal membrane? What are their names?

A
  1. Sodium ( Na+)
  2. Potassium ( K+)
  3. Calcium ( Ca2+)
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21
Q

How many anions surround the neuronal membrane?

A
  1. Chloride ( Cl-)
  2. Negatively charged proteins ( A-)
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22
Q

Are ions stationary?

A

No. Ions are in constant motion and their movement is guided by diffusion & electrostatic pressure.

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23
Q

What two things guide ion currents?

A

Diffusion & electrostatic pressure

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24
Q

What is diffusion ( concentration gradients) and its relationship to ions?

A

Diffusion guides ion movement by moving ions from areas of high to low concentration. High to low concentration.

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25
Q

What is electrostatic pressure & its relationship to ions?

A

Electrostatic pressure moves ions toward oppositely charged areas. Negative to positive or positive to negative.

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26
Q

DIffusion refers to the tendency of molecules to move from an area of (lower/higher) concentration to an area of ( higher/lower) concentration.

A

Diffusion refers to the tendency of molecules to move from an area of higher concentration to an area of lower concentration.

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27
Q

When there is a difference in concentration, what does it produce?

A

A concentration gradient.

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28
Q

What is a concentration gradient?

A

It is what happens when there is a difference in concentration.

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29
Q

Does diffusion produce an uneven or even distribution of molecules?

A

Diffusion produces an even distribution of molecules.

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30
Q

If a semipermeable membrane restricts the flow of substances, those substances that can pass will diffuse across until unequally or equally concentrated on both sides?

A

Passage of substances in a semipermeable membrane will diffuse across until equally concentrated on both sides.

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31
Q

The attraction of opposite-polarity molecules and repulsion of same-polarity molecules is known as what?

A

Electrostatic force

32
Q

Do two positive ions or two negative ions attract or repel each other?

A

Two neurons with the same charge will repel eachother.

33
Q

Do positive and negative ions repel or attract each other?

A

Attract

34
Q

What is electrostatic pressure?

A

Electrostatic pressure is derived from the distribution of electrical charges.

35
Q

Under an electrical field, will movement be towards an opposite or positive charged?

A

The opposite charge.

36
Q

Neuron membranes allow most substances from freely passing through. True or false?

A

False. The phospholipid bilayer prevents most substances from freely passing unless they are lipid soluble.

37
Q

What are passive ion channels?

A

Passive ion channels are always open and do not close.

38
Q

Passive ion channels require energy. True or false?

A

False. Passive ion channels do not require energy.

39
Q

Passive ion channels are selective because they only allow the passage of what two ions?

A

Potassium ( K+) & Chloride ( Cl-)

40
Q

Potassium ( K+) & Chloride ( Cl-) are able to pass through which ions channels?

A

Passive ion channels only allow the passage of K+ & Cl-

41
Q

Which two ions are not able to pass through passive ion channels?

A

Sodium & Calcium.

42
Q

Sodium and calcium cannot pass through what?

A

Passive ion channels.

43
Q

The presence of passive ion channels makes the membrane of the neuron what?

A

Semipermeable.

44
Q

What is equilibrium potential related to?

A

Ion movement.

45
Q

When movement of ions acrooss the cell membrane is balanced, what is this called?

A

When movements of ions across the cell membrane are balanced, equilibrium potential has been met,

46
Q

What is equilibrium potential?

A

It is the point at which movement of ions across the cell membrane is balanced.

47
Q

Electrostatic pressure pulling ions in one direction is offset by the diffusion force pushing them in the opposite direction. What is this called?

A

Equilibrium potential.

48
Q

Can you calculate equilibrium potential?

A

Yes.

49
Q

If we know the concentration of an ion, what can we calculate?

A

We can calculate equilibrium potential if we know the concentrations of the ion.

50
Q

What is Na +? Is it a cation or anion?

A

Sodium. Cation

51
Q

What is K+? Is it a cation or an anion?

A

Potassium. Cation

52
Q

What is Ca2+? Is it a cation or an anion?

A

Calcium. Cation

53
Q

What is Cl-? Is it a cation or an anion?

A

Chloride. Anion

54
Q

What is A-? It is a cation or an anion?

A

Negatively charged proteins. Anion.

55
Q

The further away the membrane potential is to the equilibrium potential, the (weaker/greater?) the force to move.

A

Greater. There is more current when you are further away from the equilibrium potential.

56
Q

What is the characteristic of the current, when the membrane potential is further away from the equilibrium potential?

A

The current is stronger. The greater the force to move.

57
Q

What is the voltage ( mV) or K+?

A

Potassium = -90mV

58
Q

What is the voltage ( mV) for Na+?

A

Sodium = 55mv.

59
Q

What is the voltage ( mV) for Ca 2+?

A

Chloride= -60 mV

60
Q

What is the voltage ( mV) of Cl-?

A

Chloride = 120 mV.

61
Q

At -90mV potassium, K+ ions are stable. What does stable mean?

A

Whatever K+ ions move inside the cell equals the number of K+ ions going out of the cell.

62
Q

What happens in a sodium-potassium pump?

A

Sodium leaks in and potassium leaks out.

63
Q

In a sodium-potassium pump, what happens to Sodium?

A

Sodium leaks in.

64
Q

In a sodium-potassium pump, what happens to potassium?

A

Potassium leaks out.

65
Q

Sodium-potassium pumps are always what?

A

Sodium-potassium pumps are always ACTIVE!

66
Q

What are the 5 cations & anions that surround the membrane?

A

NA+ , K+ , CA2+.

67
Q

Identify what these are.

A

Transporter Pumps

68
Q

Identify what these are.

A

Ion channels

69
Q

Identify what these are.

A

Voltage-gated ion channels

70
Q

Identify what these are.

A

Receptor. Transmitter-gated ion channels

71
Q

Identify what these are.

A

Receptor. G-protein coupled.

72
Q

Please describe this picture & identify what is going on.

A

This is a passive ion channel. K+ blue ( Potassium) & Cl- orange( Chloride) are allowed to pass through. Na+ Red ( sodium) & Ca2+( calcium) cannot pass through these passive ion channels.

73
Q

What process is taking place here?

A

Diffusion

74
Q

What process is taking place here?

A

Ion movement equilibrium potential.

75
Q

What is the equilibrium potential or Potassium, Sodium, Chloride, & Calcium?

A

See picture.

76
Q
A