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Py222 > Quiz2 > Flashcards

Quiz2 Flashcards

1
Q

label the parts of a neuron

A

on paper

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2
Q

give the basic description of what parts of the neuron do

A

dendrites: receive neurological information
cell body: contains nucleus and other organelles to support cell function
axon hillock: location a large electrical signal is generated
axon: transmits electrical/chemical signal
myelin: controls speed of signal

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3
Q

what is resting potential

A

difference in electrical charge between the inside and outside of a neuron
-the resting potential of a neuron is -70mV

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4
Q

why is the resting potential of a neuron negative

A
  • neurons have semi-permeable membrane, ions can move through but not easily
  • positively charged ions: K+ and Na+
  • inside of cell is negatively charged so K+ in cell is content
  • outside of cell is positively charged so Na+ wants to go in because inside is negative
  • there are more sodium ions on the outside of the cell than there are more potassium ions on the inside of cell*
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5
Q

what is the sodium potassium pump

A

pumps 2 K+ into cell and 3 Na+ ions out

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6
Q

explain the Na+ ion in neurons (relative concentration, electrostatic pressure, concentration gradient)

A

relative concentration: more outside of cell
electrostatic pressure: move in (to negative)
concentration gradient pressure: move inward

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7
Q

explain K+ ion in neurons (relative concentration, electrostatic pressure, concentration gradient)

A

relative concentration: more inside of cell
electrostatic pressure: move inward (towards negative)
concentration gradient pressure: move outward

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8
Q

explain Cl- ion in neurons (relative concentration, electrostatic pressure, concentration gradient)

A

relative concentration: more outside of cell
electrostatic pressure: move outward (toward positive)
concentration gradient pressure: move inward

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9
Q

what is an action potential

A

when cells become stimulated enough to reach -55mV, they reach a threshhold which starts an action potential

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10
Q

what are the four properties of action potential

A

1) all or nothing: either the cell fires or it doesn’t
2) propagation: once it is in motion nothing else needs to be done and its strength doesn’t decrease with the distance it travels down the neuron
3) threshold: resting potential must meet a certain number for the AP to occur
4) refractory: two periods absolute and relative, there is an upper limit to the firing rate of an AP

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11
Q

what is myelin

A
  • wraps around axons of neurons and it insulates the neuron
  • increases the speed of potential
  • myelin is “fat” but it is technically glial cells
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12
Q

what are glia cells and the types of glial cells

A

glia cells are nervous system support cells

  • oligodendrocytes myelinate axons in the brain and spine
  • schwann cells myelinate axons in the periphery of the body
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13
Q

what are postsynaptic potentials

A

local changes in electrical potential that occur near the receptor sites can make the charge of a cell more negative or positive

  • action potential leads to neurotransmitter release
  • postsynaptic receptors bind to neurotransmitters
  • binding leads to postsynaptic potentials
  • can be either excitatory or inhibitory
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14
Q

what are the differences between post-synaptic and action potentials

A
  • can be excitatory or inhibitory (not just excitatory)
  • much smaller in magnitude/ electrical charge
  • can be graded
  • lose energy over time/space
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15
Q

what is excitatory spatial summation

A
  • if multiple postsynaptic potentials come in at the same time from different spaces
  • can maybe provide enough power for AP
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16
Q

what is excitatory temporal summation

A

one postsynaptic potential occurring again and again quickly and summing enough to start the AP

17
Q

if APs are all or none how can we tell difference in a strong stimulus? (poke v stab)

A
  • more APs fire off in a smaller period of time

- or a given neuron can fire off quickly or slowly (not stronger)

18
Q

what are the mechanisms of eliminating neurotransmitters in synaptic cleft

A

1) reputake: neurotransmitter taken up by the presynaptic neurons
2) enzymatic deactivation: breaking them down
3) glial cell degradation: glial cells destroy neurotransmitter
4) autoreceptors: neurotransmitters bind to them
5) diffusion: neurotransmitters diffuse away from synapse

19
Q

when the threshold is reached and an action potential starts, what channels open first

A

the sodium channels open first, sodium rushes in

20
Q

what are the parts of a synapse

A

synapse: region of contact between the neuron containing the terminal bouton, the synaptic cleft, and the postsynaptic region

21
Q

what are the synaptic vesicles

A

small balloon like structures in and on the neuron that are filled with neurotransmitter

22
Q

what is the synaptic cleft

A

space between adjacent neurons

23
Q

what are receptors

A

specially configured proteins embedded within the post synaptic membrane that create binding sites for neurotransmitter

24
Q

what are the types of neurons

A

interneurons: transmits impulses between neurons
motor neurons
sensory neurons

25
Q

what is a node of Ranvier

A

gaps between myelinated sections of an axon

26
Q

explain depolarization, repolarization and hyperpolarization

A

depolarization: cell fires and charge goes from -55 to 40, reaching the peak
repolarization: after reaching the peak the electrical charge then retreats to baseline resting potential
hyperpolarization: the voltage becomes briefly more negative than the resting potential

27
Q

presynaptic v postsynaptic side

A

presynaptic: side of cleft that releases neurotransmitter
postsynaptic: opposite side containing the outside edge of the neighboring neuron

28
Q

what are neurotransmitters

A

molecules released from neuron that enable transmission of signals

29
Q

what is the difference between absolute and relative refractory periods

A

absolute: action potential cannot be initiated
relative: more stimulation than normal is needed to initiate an action potential (hyperpolarization)

30
Q

explain the pump throughout the phase of the action potential

A

1) sodium channels open and Na goes in (at start of AP)
2) potassium channels open and K leaves cell (during AP)
3) Na channels close (at peak of absolute refractory period)
4) K channels close (at hyperpolarization)

31
Q

what are the three functions of glial cells

A

nourishment in neurons
mylenation
breaking down neurotransmitters

Py222 (18 decks)

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