Brainscape's Knowledge GenomeTM

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


See full index

Y2 HNN > Signalling in NS > Flashcards

Signalling in NS Flashcards

1
Q

what is the role of dendrites ?

A

receives input from other cells

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

what is the role of axons?

A

key role in transmission of nerve impulses from the cell body

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

what is the typical resting membrane potential in neurons and what does this mean in terms of -ve and +ve ions?

A

-60mV to -70mV

In neurons there are more positive ions outside the cell compared to more negative ions inside the cell

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

Are Na+ ions major extracellular or intracellular ions ?

A

extracellular

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

Are K+ ions major extracellular or intracellular ions ?

A

intracellular

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

Are Cl- ions major extracellular or intracellular ions ?

A

extracellular

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

define equilibrium potential

A

membrane potential where number of ions entering the cell = number of ions leaving cell

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

define an action potential

A

An action potential is a very brief but dramatic change in membrane potential

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

what occurs during depolarisation of a neuron ?

A

Increased permeability to Na ions into the cell

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

what occurs during repolarisation of a neuron ?

A

increased permeability of K ions out of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe the process of an action potential

A

Influx of Na ions into cell
Rapid opening of voltage gated Na channels
The channels close
Voltage gated K channels SLOWLY open
K+ ions leave the cell and causes repolarisation
leads to hyperpolarisation

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

List some examples of voltage gated Na channel drugs in medicine

A

These drugs are Na voltage gated channel blockers:
Local anaesthetics
Pain treatment
Epilepsy drugs

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

describe the propagation of action potential along an axon

A

Depolarisation of a patch of neurons before and after the area, so a depolarising wave travels the length of the axon as a cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are two ways to increase the speed of propagation along an axon?

A

Increase axon diameter

Reduce number of open pores/channels in membrane to insulate axon and prevent leakage (forces )

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

What are node of Ranvier?

A

Gaps on axons between myelin sheaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe saltatory conduction

A

The action potentials jump from node (of ranvier) to node in the myelinated axon

17
Q

how does the diameter of a myelinated axon compare to an unmyelinated one?

A

Myelinated axons have wider diameter

18
Q

Describe the causes of multiple sclerosis, its effect on action potential and symptoms

A

Antibodies attack myelin sheaths in CNS, forming scars (sclerosis). This delays/blocks action potentials

Symptoms:
Blurred vision
Muscle pain
Partial paralysis
Fatigue
Lack of coordination
19
Q

Describe the causes of guillan barre syndrome and symptoms

A

It is an inflammatory disease caused by previous infection/inflammation.
Causes autoimmune attack of myelin (schwann cells) in PNS

Symptoms:
Progressive motor weakness
motor and sensory loss

20
Q

what effect does an EPSP (excitatory postsynaptic potential) have on a post synaptic membrane ? give an example of this

A

it brings it closer to the threshold (depolarisation) and increases the probability of the postsynaptic cell producing an action potential
E.g. entry of Na ions

21
Q

what effect does an IPSP (inhibitory postsynaptic potential) have on a post synaptic membrane ? give an example of this

A

It moves the post synaptic membrane further away from threshold (hyperpolarisation) and reduces the probability of the postsynaptic cell producing an action potential

22
Q

Describe temporal summation

A

high frequency of action potentials from one axon in the presynaptic neuron elicits postsynaptic potentials that summate with each other

23
Q

Describe spatial summation

A

firing of action potentials at multiple sites from one or more presynaptic neurons

24
Q

give an example of a cholinergic neurotransmitter

A

acetylcholine

25
Q

give examples of a biogenic amine neurotransmitter

A

catecholamines: noradrenaline, adrenaline, dopamine

5-HT/serotonin

26
Q

give excitatory and inhibitory examples of amino acid neurotransmitters

A

excitatory: glutamate
inhibitory: GABA

27
Q

give an example of a neuropeptide neurotransmitter

A

endogenous opioids

28
Q

what are two conditions associated with defective myelination?

A

multiple sclerosis

guillan barre syndrome

29
Q

what are two conditions associated with disruption of cholinergic synaptic transmission?

A

botulism

myasthenia gravis

30
Q

describe the cause of botulism, its effect on synaptic transmission and symptoms associated with it

A

Clostridium bacteria produce botulinum toxin which disrupts exocytosis and disrupts ACh release from motor neurons

symptoms:
skeletal muscle weakness
paralysis of diaphragm (respiratory failure)

31
Q

describe the cause of myasthenia gravis, its effect on synaptic transmission and symptoms associated with it

A

this is an inflammatory disease whereby antibodies bind to ACh receptors on post synaptic membrane at motor end plate.

Symptoms:
severe muscle weakness
particularly affects eyelids, eyes, face, throat and limb muscles

32
Q

2 ways in which information may spread in the NS is by divergence and convergence, describe the difference between them

A

Divergence: one neuron communicates with many neurons
Convergence: many neurons feed into one neuron

33
Q

list 4 tests to investigate cerebral function

A

EEG - electro-encephalography
PET - positron emission tomography
fMRI - functional magnetic resonance imaging
TMS - transcranial magnetic stimulation

34
Q

what does EEG record and how is this done?

A

Investigates cognitive processes in response to a stimulus, this is done by recording the electrical activity of the brain

35
Q

what do PET scan and fMRI investigate and how is this done?

A

locates brain activity while performing a task

Do this by measuring blood flow (PET: via a small dose of radioactive material injected into the bloodstream)

36
Q

what does TMS investigate and how is this done?

A

interrupts brain activity while performing a task

Does this by using an electromagnet to stimulate brain activity

Y2 HNN (34 decks)

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