6B - neurons Coordination Flashcards

1
Q

Resting membrane potential

A

Outside of membrane more positively charged than inside ( -70 mV )
- so membrane polarised - difference in charge ( potential difference/ voltage )

Resting potential maintained by sodium potassium pump and potassium channels
- Nak uses active transport to move 3 NA out and 2 K in ( produces electrochemical gradient )
- K channels ( facilitated diffusion) to move K out , down concentration gradient

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

Action potential

A

When neurons stimulated other ion channels ( sodium channel ) opens
- if stimulus big enough - will trigger rapid change in potential difference- cell membrane depolarised

Stimulus
Depolarisation
Repolarisation
Hyper polarisation
Resting potential maintained

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

Stimulus

A

It excites the neuron, causes the Na+ channels to open
- membrane becomes more permeable to sodium- diffuse down the electrochemical gradient into neuron
- makes the inside of neuron less negative

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

Depolarisation

A

When reach the threshold of -55mV, more Na+ channel open
More sodium ions diffuse

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

Repolarisation

A

Potential difference of around +30 mV Na+ channel closes, K+ channels opens
Membrane more permeable to potassium- diffuse out of the neuron down the potassium gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hyperpolarisation

A

K+ channel slow to close, potential difference lower then -70 mV (too many K+ ion out )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Resting potential

A

Ion channels at rest
- sodium potassium pump returns the membrane into resting potential
- maintains resting potential until membrane’s excited by other stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Action potential

A

When neurons stimulated - ion channels in cell membrane opens
If stimulus big enough - trigger rapid change in potential difference . This causes cell membrane to be depolarised

Have sequence of events
- stimuli
- depolarisation
- repolarisation
- hyper polarisation
- resting potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

refractory period

A

Ions channels recovering and can’t be opened
- acts as a time delay between one action potential to the next
- make sure action potential don’t overlap but pass along as separate impulse

Refractory period means = there is a limit to frequency at which nerve impulses can be transmitted and action potential are unidirectional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Waves of depolarisation

A
  • some sodium ions enter the neurone sideways
  • causes sodium channel in the next region of neurons to open and sodium ion diffuse into that part
  • wave move away from the refractory period - these part can’t fire action potential difference lower
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

All or nothing principle

A

Only Once threshold reached = action portential will be fired
Bigger stimulus won’t cause bigger action potential but will cause them to fire more frequently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what effects speed of conduction

A
  • myelination ( saltatory conduction )
  • axon diameter
  • temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

myeloination

A
  • nerons = have myelin sheath
  • made of schwann cell, between schwann cell tiny patches of bare membrane called nodes of ranvier
  • sodium ion channels concentrated at nodes of ranvier
  • saltatory conduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

saltatory conduction

A
  • myelinated neuron, depolarisation only happens in nodes of ranvier
  • neurons cytoplasm conducts enough electrical charge to depolarise next node
  • impluse jumps from node to node

non neylinated - impulse travels along whole length of axon membrane, so depolarisation on whole length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

axon diameter

A
  • conducted quiker with bigger diameter
  • less resisstance to flow of ions
  • less resistance = depolarisation reacher to other part of neuron quicker
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Temperature

A
  • speed of temp increases - ions diffuse faster
  • if too high, protein becomes to denature
17
Q

synaptic and neurotransmitters

A
  • draw it ( pg : 335 )
  • when Ap reach the end of neurone release NT into synaptic cleft
  • receptor only on postsynaptyic membrane - inpulses are unidirectional
  • neurotransmitor break down by enz ( so respond doesn’t keep on hapenning)
18
Q

NT you need to know

A

acetycholine (ACh)
binds to cholinergoc synapes