neuroscience - exam 3 Flashcards

1
Q

neurons

A

cells that send & receive electrical or chemical signals (nerve cells)

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2
Q

nervous systems

A

circuits of neurons that integrate internal & external

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3
Q

How do neurons and nervous systems differ in association with species complexity

A

more complex organisms have more complex nervous systems & more neurons

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4
Q

least complex organisms nervous system

A

neurons spread out

nerve net

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5
Q

nerves

A

neurons bundled

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6
Q

cephalization

A

neurons cluster in the head = brain

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7
Q

bilateral symmetry

A

both sides the same

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8
Q

central nervous system

A

brain & spinal cord

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9
Q

peripheral nervous

A

nerve cells outside the CNS

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10
Q

dendrites

A

receives signals

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11
Q

cell body

A

contains cell machinery

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12
Q

axon hillock

A

integrates signals
“decider”

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13
Q

axon

A

carries signals to synaptic terminals

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14
Q

synaptic terminals

A

send signals to other cells

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15
Q

astrocytes

A

blood-brain barrier

prevents toxins from entering the brain

nourish/support neurons

role in mental disorders

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16
Q

microglia

A

immune cells

protect brain against pathogens

clean up debris

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17
Q

oligodendrocytes

A

glial cells in CNS

wrap around axons

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18
Q

schwann cells

A

glial cells in PNS

wrap around axons

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19
Q

myelin sheath

A

encases neurons & insulates

increases signal speed

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20
Q

what disease is associated w/ myelin degeneration

A

multiple sclerosis

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21
Q

what type of signals travel down neurons

A

electrical signals

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22
Q

what type of signals travel between neurons

A

chemical signals

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23
Q

sensory neurons

A

PNS –> CNS

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24
Q

interneurons

A

“talk” to other neurons

can be CNS or PNS

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25
Q

motor neurons

A

CNS –> PNS

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26
Q

cone snail sensory, inter, & motor

A

sensory input of PNS - cone snail’s siphon senses a fish

integration - sensory input sent to CNS

motor output (PNS) - proboscis sends thing out to inject fish w/ poison

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27
Q

which type of neuron is affected by Lou Gehrig’s disease?

A

motor neuron

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28
Q

membrane potential

A

voltage across a plasma membrane

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29
Q

voltage

A

electrical charge difference

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30
Q

resting potential

A

membrane potential of a neuron that is not transmitting signals

-70mV

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31
Q

what forms the resting potential

A

differences in ions across the plasma membrane

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32
Q

distribution of ions in membrane

A

Na+ = sodium - more outside cell

K+ = potassium - more inside cell

A- = anions (negatively charged ions)

33
Q

polarization of cell

A

more positive ions outside of cell

INSIDE of cell is relatively MORE NEGATIVE than the outside

34
Q

selective permeability

A

channels only let certain things through

35
Q

are ion channels mostly open or closed in a
neuron at rest

A

closed

keeps Na+ on 1 side & K+ on the other side

36
Q

sodium potassium pump

A

moves Na+ ions out of the cell & K+ into the cell in a 3:2 ratio

active transport

37
Q

why are sodium potassium pumps important

A

for making sure the inside stays more negative

38
Q

concentration gradient w/ Na+ & K+

A

concentration gradient pressures Na+ to enter the cell

pressures K+ to exit the cell

passive transport

39
Q

voltage-gated ion channels

A

electrical signals from other neurons cause ion channels to open

change in membrane potential (voltage) causes ion channel to open

40
Q

hyperpolarization

A

inside becomes MORE negative

channel opens, K+ leaves, cell becomes more negative

41
Q

depolarization

A

inside becomes more positive

Na+ channel opens, Na+ enters, neuron becomes less negative

42
Q

graded potentials

A

depolarization & hyperpolarization under the threshold

the stronger the stimulus, the larger the change in membrane potential

43
Q

what happens when a depolarization crosses the “threshold potential”

A

action potential

not a graded response

44
Q

action potential

A

brief all-or-none depolarization of a neuron’s plasma membrane

type of signal that carries info along axons

45
Q

size & shape of action potentials

A

size & shape of each one is the same

a stronger stimulus generates more action potentials

46
Q

stages of action potential

A
  1. resting state
  2. depolarization
  3. rising phase
  4. falling phase
  5. undershoot
  6. restoration of resting potential
47
Q
  1. resting state of action potential
A

Na+ & K+ channels are closed

48
Q
  1. depolarization of action potential
A

Na+ channels open

Na+ diffuses into the cell

49
Q
  1. rising phase
A

MANY Na+ channels open

Na+ rushes into the cell

positive feedback

50
Q
  1. falling phase
A

K+ channels open

K+ rushes out of the cell

51
Q
  1. undershoot
A

K+ slowly closing

Na+ inactivated

52
Q

refractory period

A

brief period when a neuron cannot generate an action potential

53
Q
  1. restoration of resting potential
A

K+ channels close

54
Q

sodium potassium pump

A

moving Na+ inside neuron
moving K+ outside neuron

helps restore resting membrane potential

55
Q

tetrodotoxin

A

blocks Na+ channels

used by puffer fish for defense

56
Q

alpha & beta toxins

A

shifts opening & closing of Na+ channels

used by scorpions to capture prey

57
Q

apamin

A

blocks K+ channels

used by honey bees for defense

58
Q

how do action potentials move down the axon

A

the depolarization of one region of the axon stimulated depolarization of the next region

59
Q

why doesn’t the action potential move backwards

A

Na+ channels become inactivated

60
Q

what determines conduction speed of an axon

A

axon diameter

myelin sheath

61
Q

How can axons send rapid signals in humans even though axons are small

A

a myelinated axon is faster than a giant axon 40x its size

> 2000 myelinated axons can be packed into the space occupied by just 1 giant axon

62
Q

nodes of ranvier

A

gaps in myelin sheath where action potentials are generated

concentrated w/ sodium ion channels

63
Q

saltatory conduction

A

action potentials are “jumping” down the length of the axon

64
Q

synapse

A

site of communication between the synaptic terminal & another cell

65
Q

presynaptic cell

A

neuron 1

sending signal

66
Q

postsynaptic cell

A

neuron 2

receiving signal

67
Q

chemical synapses

A

a chemical acts as a signal between cells

68
Q

electrical synapses

A

electrical current flows from cell to cell

69
Q

vesicle

A

a packet of neurotransmitters

70
Q

neurotransmitter

A

a chemical messenger between neurons

71
Q

synaptic cleft

A

gap between pre & post synaptic neurons

72
Q

chemical synapse @ synaptic terminal

A
  1. action potential depolarizes presynaptic membrane
  2. voltage-gated Ca2+ channels open
    Ca2+ enters the neuron
  3. Ca2+ causes vesicle to fuse to membrane & release neurotransmitter –> exocytosis
73
Q

EPSP

A

excitatory postsynaptic potentials

depolarization

74
Q

IPSP

A

inhibitory postsynaptic potentials

hyperpolarization

75
Q

ionotropic receptors

A

neurotransmitters bind to receptors that are part of ion channels

open ion channel
change membrane potential

rapid, short lasting

76
Q

If one input to a postsynaptic neuron is usually too weak to initiate an action potential,
then how are action potentials elicited

A

synaptic integration / summation

epsp & ipsp are added together

77
Q

where does synaptic integration take place

A

axon hillock

78
Q

metabotropic receptors

A

neurotransmitters bind to a receptor that is not part of an ion channel

activates a signal transduction pathway

slower, longer lasting

can open an ion channel or activate another molecule