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Anatomy and Physiology 1 > Chapter 12 part 2 > Flashcards

Chapter 12 part 2 Flashcards

1
Q

resting neuron

A

difference in electrical signal across the cell membrane

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2
Q

difference in electrical charge=

-2 things

A

electrical potential difference = transmembrane potential

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3
Q

difference in electrical charge refers to

A

difference in charge across the plasma membrane

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4
Q

transmembrane potential

  • definition
  • how do you measure it
  • mV
  • what does the sign refer to
  • more + or - in the inside
  • key concept
A
  • varies from moment to moment depending on the cell
  • using a volt meter
  • 70mV
  • to charges inside the cell
  • more -
  • all neutral activities begin with a change in the resting membrane potential
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5
Q

what makes the resting membrane potential -70mV

A

intracellular and extracellular fluids are different from eachother because plasma membrane is selectively permeable

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6
Q

resting cell membrane

  • K+ outside the cell
  • K+ inside the cell
  • Na+ outside the cell
  • Na+ inside the cell
  • protein -
A
  • low
  • high
  • high
  • low
  • negative inside the cell
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7
Q

what is located inside the resting

-3 things

A
  1. greater concentration of K+
  2. negatively charged protein
  3. other large anionic molecules
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8
Q

what is located outside the cell in the resting cell

-1 things

A

greater concentration of Na+

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9
Q

what is responsible for establishing these concentration gradients for Na+ and K+?

A

Largely due to the Na+/K+ exchange pump

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10
Q

how leaky are sodium leak channels

A

not very leaky because the membrane in a resting neuron is not very permeable to sodium

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11
Q

how leaky are potassium leak channel?

A

very leaky

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12
Q

action potential

  • definition
  • where does it begin
  • involves
A
  • an abrupt change in the electrical potential difference across the cell membrane which occurs after a stimulus
  • at the hillock
  • another set of channel proteins in the cell membrane (voltage gated sodium channel and voltage gated potassium channel)
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13
Q

4 steps for development of an action potential

A
  1. resting neuron
  2. application of stimulus
  3. depolarization
  4. repolarization
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14
Q

application of a stimulus

  • definition
  • voltage change
A

localized change in resting potential causes depolarization to threshold
- -70 mV to -60 mV

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15
Q

depolarization

  • what happens to channels
  • what happens to plasma membrane
  • what happens to Na+
  • voltage change
A
  • voltage gated sodium channel opens when threshold is reached
  • becomes permeable to Na+
  • Na+ quickly flows down its concentration gradient
  • -60 mV to +10 mV
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16
Q

Repolarization

  • what happens to channels
  • what happens to sodium permeability and sodium movement
  • what happens to potassium permeability and movement?
  • voltage
A
  • voltage gated sodium channel closes around +30 mV and voltage gated potassium channel opens
  • stops
  • plasma membrane become permeable to K+ and it flows out of cell
  • +30 mV to -90 mV to -70mV
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17
Q

absolute refractory period

A

period when membrane cannot respond to a new stimulus

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18
Q

relative refractory period

A

Na+ channels are returning to normal resting levels and membrane can respond to a larger than normal stimulus

19
Q

impulse conduction would be faster in

-why

A

an axon with a larger diameter

-because a larger diameter offers lower resistance-ions can move more freely within the cytoplasm

20
Q

All-or-nothing principle for an action potential

A

if a stimulus is strong enough to initiate an action potential, then the action potential will be conducted at a constant magnitude and rate along the length of the axon

21
Q

an action potential at the beginning of the axon equals

A

an action potential at the end of the axon

22
Q

how does the neuron transmit info about the strength and duration of stimulus that started the action potential?

  • definition
  • 1 AP/sec produces
  • 100 AP/ sec produces
A

frequency of action potential propagation

  • produces a muscle twitch
  • produces muscle tenancy
23
Q

2 types of communication between neurons

A
  1. electrical

2. chemical

24
Q

electrical communication

-2 things

A
  • presynaptic and post synaptic membranes are locked together at gap junction
  • action potentials propagate from 1 cell to the other
25
Q

chemical communication

-2 things

A
  • cells are not directly attached to eachother

- cells use neurotransmitters to communicate with eachother

26
Q

5 events occuring at the synapse

A
  1. action potential arrives and depolarizes the synaptic knob
  2. extracellular Ca++ ions enter through open channels and trigger exocytosis of acetylcholine
  3. acetylcholine diffuses across synaptic cleft and binds to receptor on the postsynaptic membrane
  4. causes opening of Na+ channels on postsynaptic membrane= depolarization of postsynaptic membrane
  5. depolarization ends as acetylcholine is broken down into acetate and choline by acetylcholinestrase
27
Q

2 major groups of neurotransmitters

A
  1. excitatory

2. inhibitory

28
Q

excitatory neurotransmitters

A

causes depolarization of the postsynaptic membrane and promotes generation of an action potential

29
Q

inhibitory neurotransmitters

A

causes hyperpolarization of the postsynaptic membrane and supresses generation of an action potential
-will go from -70 mV to -90mV

30
Q

5 examples of neurotransmitters

A
  1. Acetyl choline (can be either)
  2. dopamine (can be either)
  3. seratonin (can be either)
  4. Norepinephrine (excitatory)
  5. Gamma-aminobutynic acid (GABA) (inhibitory)
31
Q

what does the exact effect of particular neurotransmitter depend on?

A

the receptor of the postsynaptic neuron not the neurotransmitter

32
Q

postsynaptic potential

A

develops in post synaptic membrane in response to neurotransmitter

    1. Excitatory postsynaptic potential (EPSP)
      1. inhibitory postsynaptic potential (IPSP)
33
Q

EPSP

A

causes depolarization of post synaptic membrane

34
Q

IPSP

A

causes hyperpolarization of post synaptic membrane

35
Q

how much effect do ind. postsynaptic potentials have on the postsynaptic membrane

A

minimal effect

36
Q

2 types of summation

-end result

A
  1. temporal
  2. spatial
    - action potential generation in postsynaptic cell
37
Q

temporal summation

  • definition
  • degree of depolarization of postsynaptic membrane
  • key concept
A
  • increased frequency of stimulus applied at a single synapse
  • increases every time an action potential causes the release of a neurotransmitter from the pre-synaptic neuron
  • series of small steps brings the hillock to threshold
38
Q

spatial summation

  • definition
  • how many synapses are activated at the same time
A
  • simultaneous stimuli applied at different locations have cumulative effect
  • multiple synapses activated at the same time
39
Q

5 functional organization of neurons

A
  1. diverging
  2. converging
  3. serial
  4. parallel
  5. reverberating
40
Q

diverging
-definition
-permits what
ex

A
  • spread of info from one neuron to several neurons
  • permits a broad distribution of signal
  • occurs when sensory neurons bring info to CNS
41
Q

converging

  • definition
  • ex
A
  • several neurons synapse on a signal postsynaptic neuron

- subconscious and conscious control of breathing

42
Q

serial

  • definition
  • ex
A
  • info relayed in a stepwise fashion

- sensory info relayed from 1 part of brain to another

43
Q

parallel

  • definition
  • example
A
  • several neurons process same info simultaneously

- complex response when stepping on a sharp object

44
Q

reverberating

  • definition
  • ex
A
  • like a positive feedback loop that involves neurons

- very complicated circuits in the brain that control consciousness

Anatomy and Physiology 1 (17 decks)

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