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Biopsychology (Year 1) > Action Potential > Flashcards

Flashcards in Action Potential Deck (45)
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1
Q

What is the function of the dendrite?

A

Receives signals from other neurons/sensory receptor cells and activates action potential
- shoots electrical charge down axon

2
Q

What is the function of the myelin sheath?

A

Insulates the axon so impulses travel faster

3
Q

Where is the sensory neuron found?

A

In receptors e.g. eyes

4
Q

What do sensory neurons do?

A
  • Carry nerve impulses to the spinal chord and the brain

- These impulses are translated into ‘sensations’ when they reach the brain e.g. vision

5
Q

What is the axon?

A

Long nerve fibre that carries nerve impulses in the form of an electrical signal known as action potential

6
Q

What do motor neurons do?

A
  • in CNS

- Control muscle movements

7
Q

What happens when a motor neuron is stimulated?

A
  • neurotransmitters are released
  • they bind to receptors on muscles
  • triggers response (movement)
8
Q

What is the axon terminal?

A

Connects neuron to other neurons

9
Q

When do neurons transmit signals?

A
  • when stimulated by sensory input

- when triggered by neighbouring neurons

10
Q

What are synapses?

A

‘Contact points’

11
Q

What are the chemical messengers that are activated when AP runs down to the end of the axon?

A

Neurotransmitters

12
Q

What are excitatory neurotransmitters?

A

Increased chance of AP

13
Q

What are inhibitory neurotransmitters?

A

Decreased chance of AP

14
Q

Why do we need membranes within the body?

A
  • body is electrically neural, but some parts are more + or - than others
  • as opposite charges attract, we need membranes to keep + and - separate till we can use the energy their attraction creates
15
Q

In what way do neurons send messages?

A

Electrochemically

16
Q

What charge does potassium sodium, calcium and chloride have?

A
  • potassium = +
  • sodium = +
  • calcium = ++
  • Chloride = -
17
Q

What are the nerve cells surrounded by?

A

A semi permeable membrane that allows some ions in and blocks others

18
Q

What is resting membrane potential?

A

When a neuron is not sending a signal, it is at rest and has a negative charge in comparison to the outside

19
Q

What does the pump do?

A

Uses energy to move 3x sodium out for every 3x potassium in

20
Q

What is the resting potential?

A

Difference in forces inside and outside

- is usually -65mV as at rest, a neuron has more positive ions outside

21
Q

What does polarised mean?

A

When there is negative membrane potential

22
Q

When does AP occur?

A

When a neuron sends info down an axon (away from a cell body) when some event causes the resting potential RP Mv to move toward 0Mv

23
Q

What is AP?

A

Electrical activity created by a depolarising current

24
Q

What happens when depolarization reaches -55Mv?

A
  • ‘threshold’ level

- neuron will fire an action potential

25
Q

Why are AP’s described as all or nothing events?

A

For any given neuron the size of the AP is always the same

26
Q

What does the neuronal membrane do?

A

Separates the charges and provides the potential to convert electricity into something useful

27
Q

What is intracellular fluid?

A

Fluid in cell

28
Q

What is extracellular fluid?

A

Fluid outside the cell

29
Q

What causes electrical signals?

A

Movement of ions across the neuronal membrane

30
Q

What 2 forces determine the movement of ions into and out of the cell?

A
  1. Concentration (high to low)

2. Electrical (negative and positive)

31
Q

What do ion channels do?

A

Only allow specific ions to move through the neuronal membrane
- different ions have different ion channels

32
Q

What happens to sodium ions channels at rest?

A

They are closed

33
Q

Why is K+ attracted to the cell?

A

Because the cell is more negative inside compared to the outside (electrical force)

34
Q

Why is K+ attracted out of the cell?

A

Because there is less potassium outside the cell (concentration force)

35
Q

What 2 forces are in equilibrium in regard to the movement of K+?

A

Concentration force and Electrical force

36
Q

What is the function of the Na+ K+ pump?

A

Causes the charge imbalance by continually pumping 3x sodium out for every 2x potassium in

  • causes increased K+ conc. inside
  • increased Na+ conc outside
37
Q

What happens to the equilibrium when a neuron is stimulated?

A

The equilibrium is upset and if the stimulation is large enough (above the -50 threshold), the resting potential becomes an action potential

38
Q

What happens when a cell is stimulated above threshold?

A

Sodium channels open

39
Q

Why is sodium attracted into the cell?

A
  • There is more Na+ outside than inside (concentration force)
  • The cell is negatively charged (electrical force)
40
Q

What type of ion channel is a potassium ion channel?

A

Voltage gated

41
Q

What is myelin produced by?

A

Glial cells

42
Q

Why do myelinated axons conduct APs faster?

A

Saltatory conduction

43
Q

What is the strength of the stimulus denoted by?

A

Increasing firing rate

- the no. Of AP’s denotes the force of the stimulus

44
Q

What happens when the AP reaches the presynaptic terminal?

A

A chemical (neurotransmitter) is released into the junction between the neurons (synapse)

45
Q

What is shown about excitatory and inhibitory signals in epilepsy?

A

The correct balance of EPSP and IPSP signals is necessary for the proper working of the nervous system
- Epilepsy results in neurons becoming too active, resulting in uncontrollable patterns of electrical activity (seizures)