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Flashcards in Neural Integration Deck (46):
1

K+ ions are held inside the cell due to a charge of

-90mV

2

Na+ are held outside the cell due to a charge of

+60mV

3

The overall resting membrane potential of a neural cell is

-70mV

4

A neural membrane is more permeable to which ions

K+ ions

5

What does an action potential cause

Membrane permeability allowing Na+ to flood into the cell causing a spike in charge

6

An upward deflection in membrane potential is called what

Depolarisation

7

An downward deflection in membrane potential is called

Hyperpolarisation

8

Polarity is defined as

A distance away from zero

9

Repolarisation is defined as

Returning back to resting membrane potential

10

A graded potential is

Small natural fluctuations in membrane potential that does not reach threshold potential so no action potential is caused

11

How does an action potential travel down an axon without losing power

depolarisation opens voltage gated Na+ channels allowing Na+ in further repolarising that area

12

What gates do voltage gated Na channels have

A fast activation gate and a slow deactivating gate

13

When do voltage gated sodium channel gates work

They both work at the same time but the activation gate opens instantly whilst the inactivation gate closes at a slower rate allowing Na to spill in

14

When do voltage gated sodium channel gates return to their original position

When membrane potential has dropped below threshold potential

15

What gates do voltage gated potassium channels have

Just a slow opening gate

16

When is the gate of the voltage gated potassium channel opened

During the rise of the action potential

17

What ramifications come about because the voltage gated sodium channel is slow to close

The action potential rises to its peak then hyperpolarises the membrane potential on the way back down

18

What is the absolute refractory period

The period that voltages gated sodium channels are in their inactive state with their inactive gate closed preventing the action potential from going back up the axon

19

What is the relative refractory period

When another AP can be fired but it has to be a stronger stimuli because the membrane potential is currently hyperpolarised due to slow closing gates on the voltage gated potassium channels

20

Two things that increase action potential velocity

Diameter of the axon
Myelination of the axon

21

The parts between the myelin sheaths in the axons are called?

Nodes of Ranvier

22

Synaptic transmission involves converting an electrical signal into

A chemical signal

23

What type of receptors respond to ACh

Cholinergic such as
Nicotinic
Muscarinic

24

What receptor is activated by noradrenalin

Adrenergic receptors

25

Briefly outline how neutrons communicate between themselves

Action potential depolarises axon terminal
Depolarisation opens voltage gated calcium channels
Ca2+ enters nerve cell triggering executors is of synaptice vesicle contents
Neurotransmitter diffuses across synaptic cleft binding with receptors on post synaptic cell
Response initiated in post synaptic cell

26

What is the major excitatory neurotransmitter used in the body

Glutamate

27

What is the main inhibitory neurotransmitter used in the body

GABA

28

How are neurons named?

By the neurotransmitter they release

29

What is an ionotropic receptor

A receptor that is also a channel that allows ions to travel through when activated by a neurotransmitter

30

What is a metabotropic receptor

A G protein-coupled receptor that causes a response leading to a series of intracellular actions when stimulated

31

Why does the neuromuscular junction only need one AP to elicit a response in the muscle

Because a lot of ACh is released and there are a huge number of ionotropic receptors on the muscle allowing a lot of Na+ to pass through and depolarise the cell

32

What enzyme cleans up and breaks down ACh to prevent more than one response of the muscle from on AP in the neuromuscular junction

Acetylcholorestarase

33

What does the peripheral nervous system include

The afferent and efferent pathways which link to the CNS

34

What type of neuron is found in the CNS why might in inhibit some efferent pathways and excite others

Interneurons. It prioritises which effects are more important. Protecting your crutch from a pit bull is more important than blocking the sun from your eyes. This is why our nervous system is so complex and not hard wired

35

Explain a divergent pathway

One pre synaptic neuron connecting to multiple post synaptic neurons

36

Explain a convergent pathway

Multiple pre synaptic pathways converge on fewer post synaptic neurons

37

Where do pre synaptic neurons attach to post synaptic neurons

At the cell body

38

Does a neuron's cell body receive one AP at a time?

No. It will receive multiple at any given time

39

An EPSP is

Excitatory postsynaptic potential

40

An IPSP is

Inhibitory post synaptic potential

41

Can EPSPs and IPSPs work together or are they independent

They can work together to summate spatially or temporaly

42

Describe spatial summation

When multiple graded potentials arrive at the axon hillock together generating an AP that is above threshold when if they had arrived at different times they would not have been strong enough

43

Describe temporal summation

When multiple graded potentials arrive at the trigger zone in quick succession making them able to generate an AP when on their own they wouldn't have been able to

44

What is presynaptic inhibition

When an inhibitory neuron prevents selected target cells from being activated but allows others to be activated through a divergent neuron

45

Describe post synaptic inhibition

The entire neuron is inhibited resulting in no target cells being activated

46

Would a larger alpha motor neurone or a smaller one be able to reach threshold easier

The smaller one, less distance for the graded potential to travel and Peter out