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BioSci107 Finals > Neurons Intro: Resting Membrane Potential > Flashcards

Neurons Intro: Resting Membrane Potential Flashcards

1
Q

Equation for the nervous system

A

Nervous system = CNS + PNS

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2
Q

What is the challenge for neuroscience

A

To prevent and treat neurological and psychiatric disorders

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3
Q

4 examples of neurological and psychiatric disorders

A
  1. Alzheimer’s
  2. Motoneuron
  3. Parkinson’s
  4. Autism
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4
Q

What are neurons (nerve cells)

A

The principal building blocks and instruments of communication in the brain

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5
Q

Structure and communication are important parts of…

A

Neurons

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6
Q

What are glia cells

A

Supporting cells

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7
Q

What are the 2 methods of communication

A
  1. Electrical signals (dendrites, cell body, axon)
  2. Chemical signals (synapses)
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8
Q

What direction do synaptic potentials flow

A

Towards the cell body

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9
Q

What direction do action potentials flow

A

Away from the cell body

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10
Q

4 features of neurons and their functions

A
  1. Dendrites: receive electrical input
  2. Cell body: passively conducts electrical input
  3. Axon: propagate action potentials
  4. Axon terminal: release chemical signals
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11
Q

What do electrodes measure

A

Electrodes measure difference between them with reference electrode as reference

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12
Q

What does every cell have

A

Resting membrane potential (mostly all have -ve resting membrane potential)

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13
Q

In neurons and their _____, the cytosol has a potential that is __ to __mV lower (more __) than the potential of the _____ fluid

A

In neurons and their PROCESSES, the cytosol has a potential that is 50 to 70mV lower (more -ve) than the potential of the EXTRACELLULAR fluid

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14
Q

Why are only neurons and muscle fibres considered ‘excitable tissues’?

A

They can suddenly respond with a transient change of this potential (ie: action potential) in response to stimulus

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15
Q

How are intracellular potentials measured today?

A
  1. Microelectrode recording technique
  2. Patch-clamp technique
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16
Q

What technique to measure intracellular potentials “compare to ground/reference electrode”

A

Microelectrode recording technique

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17
Q

What technique to measure intracellular potentials “membrane ruptures so intracellular fluid is continuous with the pipette”

A

Patch-clamp technique

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18
Q

By convention the potential _____ the cell is defined as ‘___’. Therefore the _____ potential is normally _____ zero (eg: -65mV)

A

By convention the potential OUTSIDE the cell is defined as ‘ZERO’. Therefore the INTRACELLULAR potential is normally BELOW zero (eg: -65mV)

19
Q

What 2 things can potential outside cell ‘zero’ and intracellular potential below -65mV be caused by?

A
  1. Unequal concentrations of Na+ and K+ inside and outside the cell resulting in the electrochemical gradients driving the movement of these ions
  2. Unequal permeability (P) of the cell membrane to these ions
20
Q

What generates the resting membrane potential (RMP)?

A

Electrical potential difference (50-70mV) across cell membrane. Results from separation of charge so there is more -ve charge inside the cell vs. extracellular fluid

21
Q

What ion has a conc. higher inside the neurons and lower outside the neurons

A

K+ ions

22
Q

What ion has a conc. lower inside the neurons and higher outside the neurons

A

Na+

23
Q

How are concentration gradients for K+ and Na+ maintained?

A

Na+/K+ pump

24
Q

How does the Na+/K+ pump work to give ratio

A

Use 1ATP, pump out 3 Na+ ions and take in 2 K+ ions

25
Q

Are the ion channels in neurons selectively permeable or fully permeable to ions

A

Selectively permeable to ions

26
Q

What are the 2 types of channels of ion channels in neurons

A
  1. Non-gated (‘leak’) channels
  2. Gated channels
27
Q

What type of channel “open at rest (‘on-off’ state), allow for diffusion of ions”

A

Non-gated (‘leak’) channels

28
Q

Type of channel these “voltage-gated, ligand-gated, mechanically gated” are categorised as

A

Gated channels

29
Q

True or false gated channels are closed at rest

A

TRUE

30
Q

In cell membranes of neurons, there are ___ leak K+ channels, but _____ leak Na+ channels

A

In cell membranes of neurons, there are MANY leak K+ channels, but FEW leak Na+ channels

31
Q

Eq for the (P) membrane permeability at rest

A

PK+/PNa+ = 40/1
K+ greater diffusion and lower Na+ diffusion

32
Q

The concept of the ‘equilibrium potential’ for one ion type is…

A

An intracellular potential at which the new flow of ions is 0 according to its electrochemical gradient

33
Q

What equation is used to calculate equilibrium potential for each ion

A

Nernst Equation

34
Q

What is the approx. value for equilibrium potentials of Na+ in mammalian neurons

A

ENa = +60mV

35
Q

True or false; glia cells have leak channels for both K+ and Na+

A

FALSE; glia cells have leak channels ONLY for K+

36
Q

What is the RMP in glia cells

A

RMP = EK -80mV

37
Q

Neurons have leak channels for ___, ____ and ____ which will affect RMP

A

Neurons have leak channels for BOTH K+ and Na+ which will affect RMP

38
Q

The higher the permeability of the cell membrane to an ion the….

A

More this ion shifts the RMP towards its own equilibrium potential

39
Q

At ___ in neurons, the membrane permeability is much ____ to K+ than to Na+, therefore the RMP is ____ to the equilibrium potential for___ (EK) than the equilibrium potential for ___ (ENa)

A

At REST in neurons, the membrane permeability is much HIGHER to K+ than to Na+, therefore the RMP is CLOSER to the equilibrium potential for K+ (EK) than the equilibrium potential for Na+ (ENa)

40
Q

Compared to glial cells, neurons RMP less negative than EK (-65mV)

A

Due to small contribution of leak Na+ channels

41
Q

What is needed to be considered for calculating RMP

A

BOTH concentration gradients and relative permeability of resting cell membrane to K+ and Na+ ions

42
Q

PK =

A

40

43
Q

PNa =

A

1

44
Q

What type of K+ and Na+ channels are responsible for RMP

A

Non-gated (leak) channels

BioSci107 Finals (11 decks)

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