Brainscape's Knowledge GenomeTM

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


See full index

Psychobiology > Unit 7 > Flashcards

Unit 7 Flashcards

1
Q

What is the main function of neurones?

A

receive and process information from neurones and sensory receptors
send information to next neurone in chain of command or effector organs

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

What is the surface of dendrites lined with?

A

synaptic receptors
-> allow to receive stimulation

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

What are dendritic spines?

A

cover many dendrites
increase surface area

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

Are synapses also possible on surface of cell bodies?

A

yes
-> also covered in synaptic receptors

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

Axon

A

thin fibre of constant diameter
covered in myelin sheath
interruptions in myellin sheath
-> nodes of ranvier

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

How many axons do neurones have?

A

1
-> can have many branches

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

Presynaptic terminal

A

swelling at end of each axon
-> allows release of neurotransmitters into synapse

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

What does the surface of neurones consist of and what is its purpose?

A

cell membrane
-> impermeable
separates inside of cell from external environment

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

What is extermely important for creating a nerve impulse?

A

protein channels
-> allow controlled flow of important molecules (e.g. water, oxygen, etc.)

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

What type of transmission does our nervous system use to communicate information?

A

electrochemical transmission

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

How did the nervous system evolve to fix the issue of an electrical impulse losing strength over longer distances?

A

By regenerating the message at various points along the axon

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

How fast are impulses conducted?

A

1-100 m/s

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

What are Ions?

A

Two parts with exactly opposite charge
can be seen when electrolytes are dissolved in water

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

Which forces act on ions?

A

Electrostatic pressure
Diffusion

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

Electrostatic pressure

A

causes ions to move towards opposite electrical charge

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

What is electrical potential?

A

difference between areas of positivity and negativity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Diffusion

A

causes ions to move towards areas of relatively lower concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the difference in concentration of two ions refered to and what is the difference in electrical potential refered to?

A

concentration gradient
electrical gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is membrane potential produced by and what is it?

A

forces of electrostatic pressure and diffusion
difference in electrical charge between inside and outside of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the membrane at rest and what does that mean?

A

polarised
electrical potential inside membrane being slightly negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is resting potential?

A

voltage between inside and outside of cells at rest
usually around 70 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Selective permeability

A

some molecules can pass through it freely
others need membrane channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Concentration of ions at rest

A

more Na+ on outside and k+ inside the cells
inside more negative
Na+ wants to enter
-> wall impermeable to Na+
K+ at equilibrium
-> electrostatic pressure and diffusion equally at play

24
Q

How does a neurone deal with Na+ and K+ ions leaking every once in a while?

A

sodium-potassium pumps
3 Na+ out
2 K+ in

25
Q

How does the inside of the cell stay negative?

A

organic anions (A-)
unable to pass through cell membrane
Chloride ions (Cl-)
-> however mostly outside the cell body
-> again at equilibrium

26
Q

Why does the cell use so much energy at sodium-potassium pumps? (about 40%)

A

cells are always ready for action

27
Q

What happens when you apply a negative charge to the cell membrane?

A

hyperpolarisation

28
Q

What happens when you apply a positive charge to the cell membrane?

A

depolarisation

29
Q

What happens when the threshold of excitation is reached?

A

massive depolarisation
causes voltage-gated Na+ channels to open
-> rapid influx of Na+
potential shoots up further towards positivity
-> action potential

30
Q

All-or-none law

A

any depolarisation reaching threshold of excitation produces action potential

31
Q

What can vary between action potentials of neurones and what stays consistent?

A

strength and speed vary between neurones
stay the same for each neurone
-> neurones either fire, or don’t

32
Q

What happens at the end of the action potential?

A

membrane potential reversed (inside more positive than outside)
-> Na+ channels snap shut

33
Q

When do K+ channels open?

A

at slightly greater levels of depolarisation
-> a bit later than Na+ channels

34
Q

What else helps the neurone repolarise?

A

Cl- influx

35
Q

What is the process of returning to negativity known as?

A

repolarisation

36
Q

What produces hyperpolarisation?

A

K+ channels remain open for a while longer
-> more K+ leave cell to lower concentration
-> repolarisation continues past resting potential

37
Q

How is the resting potential finally restored?

A

closing of K+ channels
sodium-potassium pump ensures right concentration of Na+ and K+ on each side

38
Q

refractory period

A

time during which a neurone is unable or less likely to produce another action potential
initial part: absolute refractory period
-> impossible to produce another AP
second part: relative refractory period
-> neurones require larger than normal stimulation

39
Q

How does action potential move down the neurone?

A

moves from cell body to end of axon
Na+ flow inside axon to neighboring areas of negativity
-> causes neighboring area to become more positive and reach threshold of excitation
-> AP regenerated
=> proagation of AP
only in direction of axon terminal because of refractory period

40
Q

Can AP occur anywhere?

A

no, only at nodes of ranvier due to absence of NA+ channels in myelinated parts of axon

41
Q

Na+ diffuses towards next node of ranvier where AP is generated again.
How is this form of conduction called?

A

saltatory conduction

42
Q

Why is saltatory conduction efficient?

A

speeds up propagation of AP
-> don’t have to occur at every point along axon
maintains strength of impulse
-> because of periodical regeneration
conserves energy
-> less sodium-potassium pumps needed

43
Q

Multiple sclerosis

A

autoimmune disease
immune system attacks myelin sheath
most axon potentials die out between nodes of ranvier due to absence of Na+ channels in unmyelinated parts
Symptoms: visual impairments, poor muscle coordination, fatigue, etc.

44
Q

postsynaptic potential

A

change in membrane potential of postsynaptic neurone after receiving stimulation from presynaptic neurone

45
Q

Why is postsynaptic potential known as a type of graded potential?

A

stimulation of postsynaptic neurone doesnt always cause mebrane to reach threshold of excitation

46
Q

Action potentials along axon vs postsynaptic potentials

A

along axon: always depolarisations
postsynaptic: depolarisation (excitatory) or hyperpolarisations (inhibitory)

47
Q

Excitatory postsynaptic potential

A

EPSP
result of an influx of Na+ into postsynaptic membrane
quickly decays if threshold of excitation isnt reached

48
Q

What is temporal summation?

A

if time between multiple ESPS is short enough they add up
-> helps reach the threshold of excitation

49
Q

What is spatial summation?

A

Several presynaptic neurones stimultion postsynaptic neurone

50
Q

Inhibitory post-synaptic potential

A

IPSP
pushes postsynaptic potential further away from threshold of excitability
decreases likelihood of postsynaptic neurone firing

51
Q

What did Loewi find out and how?

A

most presynaptic neurones communicate messages via neurotransmitters
Stimulated vagus nerve in one frog
-> decreases heart rate
collected fluid and transferred it to second frog’s heart
-> heart rate also decreased

52
Q

Where are smaller and bigger neurotransmitters synthesised?

A

Smaller: axon terminal (e.g. monoamines)
larger: cell body and carried down (e.g. neuropeptides)

53
Q

The activation of which type of voltage-gated channels causes and influx leading to the release of neurotransmitters in the presynaptic terminal?

A

Ca2+ channels
influx of Ca2+

54
Q

What causes postsynaptic ion channels to open?

A

neurotransmitter diffusing to receptors

55
Q

What are the methods used to remove neurotransmitters from the synapse to prevent overstimulation?

A

Breaking them down
-> e.g. acetylcholine broken down by acetylcholinesterase into acetate and choline
-> choline re-synthesised in terminal
Reuptake: for other neurotransmitters like some monoamines, acheived by using transporter proteins
Diffusing away from synapse

56
Q

Negative feedback

A

used to limit release of neurotransmitters of presynaptic neurone
2 ways:
1) many have autoreceptors that detect release of neurotransmitters and inhibit further release
2) some postsynaptic neurones release chemicals (e.g. nitric oxide) to inhibit further release

Psychobiology (7 decks)

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