Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ESA 2 Membranes and Receptors > Resting Membrane Potential (3) > Flashcards

Resting Membrane Potential (3) Flashcards

0
Q

How is membrane potential measured?

A
  • Microelectrode penetrates cell membrane
  • Microelectrode contains conducting solution
  • Circuit set up with voltmeter to read potential difference
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Why is membrane potential important in cells?

A
  • Provides basis of signalling in nervous system and cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the membrane potential?

A
  • Potential inside cell relative to extracellular solution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the ranges of resting potentials in the following?

  • Animal cells
  • Cardiac/skeletal cells
  • Nerve cells
A
  • Animal: -20 to 90mv
  • Cardiac/skeletal: -80 to -90mv
  • Nerve: -50 to -75mv
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Compare the intra/extra cellular concentrations of the following:

  • Na+
  • K+
  • Cl-
  • A-
A
  • Na+ 10/145mM
  • K+ 160/4.5mM
  • Cl- 3/114mM
  • A- 167/40mM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give examples of other anions that are transported across cellular membranes.

A
  • Phosphate
  • Bicarbonate
  • Amino acids
  • Charged groups on proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When at resting potential what movement is there of K+?

A
  • K+ from inside to out via chemical gradient
  • K+ from out to inside via electrical gradient
  • Balanced so no net movement.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the Nernst equation and state it.

A
  • Allows calculation of membrane potential at which X is at equilibrium given intra and extracellular X concentrations
  • Ex = 61/Z log ((X outside)/(X inside))
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How much K+ is need to set up resting potential?

A
  • V. small
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In cardiac and skeletal cells why is their resting potential not exactly Ek?

A
  • Cells are never perfectly selective for K+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is depolarisation?

A
  • Decrease in size of membrane potential from its normal value
  • Cell interior is less negative
  • e.g. -70mv to -50mv
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is hyperpolarisation?

A
  • Increase in size of membrane potential from normal value
  • Cell interior becomes more negative
  • e.g. -70 to -90mv
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do membrane potentials arise?

A
  • Result of selective ionic permeability.

- Changing selectivity will change membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does increasing the permeability to certain ions result in?

A
  • Moves membrane potential towards the equilibrium potential for that ion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the equilibrium potential for the following?

  • K+
  • Na+
  • Cl-
  • Ca2+
A
  • K+ -95mv
  • Na+ +70mv
  • Cl- -96mv
  • Ca2+ +122mv
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which ions’ movement can result in hyperpolarisation and why?

A
  • K+ as moves out of cell making it more negative inside the cell
  • Cl- as moves into the cell making inside more negative
16
Q

Which ions’ movement can result in depolarisation?

A
  • Na+ and Ca2+ as both move into the cell making it less negative
17
Q

What are the 3 types of gating?

A
  • Ligand
  • Voltage
  • Mechanical
18
Q

What are ligand gated channels?

A
  • Channels that open/close in response to binding of chemical ligand
  • e.g. Channels at synapses that respond to extracellular transmitters/Intracellular messengers
19
Q

What are voltage gated channels?

A
  • Channels that open/close in response to a change in membrane potential
  • e.g. AP related channels
20
Q

What are mechanical gated channels?

A
  • Opening/closing in response to membrane deformation

- e.g mechanorecepotors.

21
Q

Where can synaptic connections occur between?

A
  • Nerve: nerve/muscle/gland/sensory
22
Q

What is fast synaptic transmission?

A
  • Receptor is also on ion channel

- Transmitter binding causes channel to open

23
Q

What do excitatory transmitters do?

A
  • Open ligand gated channels causing membrane depolarisation
24
Q

What are excitatory synapses permeable to?

A
  • Na+ and Ca2+

- nAChR

25
Q

What is the resulting change in membrane potential known as?

A
  • Excitatory post-synaptic potential (EPSP)
26
Q

How are excitatory synapses controlled?

A
  • Amount of transmitter
  • Acetylcholine
  • Glutamate
27
Q

What do inhibitory synapses do and what are they permeable to?

A
  • Opening of ligand gated channels to cause hyperpolarisation
  • K+ and Cl-
28
Q

What types of transmitters regulate inhibitory synapses?

A
  • Glycine

- Gamma-aminobutyric acid (GABA)

29
Q

What is slow synaptic transmission?

A
  • Receptor and channel proteins are separate.
30
Q

What are the two types of slow synaptic transmission?

A

1) Direct G-protein gating
- Localised
- Quite rapid
2) Gating via Intracellular messenger
- G protein stimulates enzyme cascade which leads onto an intracellular messenger/protein kinase stimulating channel opening.
- Throughout cell
- Amplification by cascade

31
Q

What are the two main factors influencing membrane potential?

A
  • Changes in ionic concentration

- Electrogenic pumps

ESA 2 Membranes and Receptors (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions