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Anatomy and Physiology > Chapter 19 > Flashcards

Chapter 19 Flashcards

1
Q

What is a membrane potential?

A

-the differences in electrical charges across the plasma membrane

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2
Q

How does the potential on the outside of a cell compare to he potential on the inside?

A
  • outside: positive

- inside: negative

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3
Q

What does it mean to be polar?

A

-the membrane has a negative pole and a positive pole

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4
Q

What does depolarized and hyperpolarized mean?

A
  • depolarized: moving more positive from the -70mV to the +30mV
  • hyperpolarized: becoming more negative than -70mV
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5
Q

What is resting membrane potential?

A
  • -70mV

- when the neuron is not conducting electrical signals

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6
Q

What are gated channels?

A

-allow specific molecules to diffuse across the membrane only when the gate channel is opened

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7
Q

In what direction does potassium and sodium move?

A
  • potassium leaves the cell

- sodium enters the cell

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8
Q

What are stimulus gated channels?

A

-ion channels that open in response to a sensory or chemical stimulus

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9
Q

What are voltage gated channels?

A

-ion channels that open in response to voltage fluctuations

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10
Q

How does the sodium potassium pump contribute to the resting membrane potential?

A
  • it pumps 3 sodium ions out of the cell
  • it pumps 2 potassium ions into the cell
  • ‘pumpkin” - pump k+ in
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11
Q

How do the leaky channels contribute to the resting membrane potential?

A
  • they allow some potassium to leave the cell

- it causes the outside to stay more positive

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12
Q

What is a local potential?

A

-the slight shifts away from the resting membrane but not big enough for an action potential

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13
Q

What is excitation? This causes which channels to open? How does this affect membrane potential?

A
  • depolarization
  • stimulus triggers the opening of the Na+ channels
  • the inside of the cell becomes way more positive
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14
Q

What is inhibition? This causes what channels to open? How does this affect membrane potential?

A
  • hyperpolarization
  • stimulus triggers the opening of the K+ channels
  • the inside of the cell becomes more negative than the original resting potential
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15
Q

Local potentials are also called what?

A

-graded potentials

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16
Q

A local potential’s depolarization is related to the magnitude of the stimulus in what way?

A

-the amount of depolarization equals the amount of the stimulus

17
Q

Where do local potentials travel?

A
  • they are isolated to one region of the plasma membrane

- don’t travel to the end of the neurons

18
Q

What is summation?

A

-the adding of local potentials in the attempt to reach the threshold potential thus creating an action potential

19
Q

What is an action potential?

A

-membrane potential of an active neuron

20
Q

What is the refractory period? Absolute? Relative?

A
  • brief period which a local area of an axon’s membrane resists restimulation
  • absolute: 0.5 ms after the threshold potential is surpassed it WILL NOT respond to any stimulus
  • relative: the membrane is repolarizing but only responds to very strong stimuli
21
Q

How does the magnitude of the stimulus relate to the action potential?

A

-the increase of magnitude of the stimulus causes a higher frequency NOT a higher response

22
Q

How are action potentials conducted down the axon?

A
  • as the reversal in polarity happens, the channels open and close
  • this happens all along the membrane, one segment after another
23
Q

Can action potentials move in either direction?

A
  • no, only afferent or efferent

- the refractory period makes sure of this

24
Q

What is the myelin sheath?

A

-insulated areas that resist ion movement

25
Q

What are the nodes of ranvier?

A

-gaps in the myelin sheath where the electrical changes occur at

26
Q

How does the myelin sheath and nodes of ranvier influence an action potential?
What type of conduction is this called?

A
  • the action potential leaps from one node to another making this much quicker
  • saltatory conduction
27
Q

What influences the speed of the action potential?

A
  • Diameter: larger diameter, faster conduction

- Myelination: myelin sheaths cause it to happen more rapidly

28
Q

What are the fastest nerves? Slowest?

A
  • fastest: motor nerves; 130 meters per second

- slowest: sensory nerves; 0.5 meters per second

29
Q

What is a synapse?

A

-a place where signals are transmitted from one neuron to another

30
Q

What are the two types of synapses?

A
  • electrical: joined by gap junctions

- chemical: use neurotransmitters to send signals

31
Q

What are the three components of a chemical synapse?

A
  • synaptic terminal
  • synaptic cleft
  • plasma membrane of postsynaptic neuron
32
Q

How do MAOIs, SSRIs, and NRIs work?

A
  • MAOIs: block the enzyme monoamine oxidase from breaking down dopamine or serotonin
  • SSRIs: inhibit the reuptake of serotonin
  • NRIs: reduce the reuptake of norepinephrine
33
Q

What are ionotropic receptors?

A

-channels that allow ions to bind directly

34
Q

What are metabotrophic receptors? Example

A
  • channels that will cause a chain of chemical reactiosn
  • will eventually open or close ion channels
  • metabolic pathway
35
Q

What are the pros and cons of metabotrophic receptors?

A
  • pros: lasts longer, can regulate other cellular processes

- cons: slower

36
Q

What are the different structural classifications of neurotransmitters?

A
  • small: acetylcholine, amines, amino acids, others

- large: neuropeptides

37
Q

What is the function of a diverging circuit?

A

-information can be split or copied and sent to different destinations

38
Q

What is the function of a converging circuit?

A

-information from many different pathways can be funneled into a single pathway

Anatomy and Physiology (19 decks)

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