Experiments Flashcards

1
Q

what is Bernstein’s Membrane Hypothesis?

A
  1. asymmetric gradient of ions inside and outside cells
  2. resting membrane potential more permeable to K+ ions
  3. action potential due to transient increase in permeability to all ions
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2
Q

what is Bernstein’s predictions?

A
  1. action potential should be accompanied by increased membrane conductance.
  2. voltage should approach 0mV at peak of action potential
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3
Q

what did Galvani do?

A
  1. He attached electric circuit to the nervous system of frogs.
  2. He believed that the observed muscle twitch upon completion of electric circuit indicated that animals’ tissues could generate electricity.
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4
Q

what did Volta do?

A
  1. he disagreed with Galvani.

2. he argued that the current was produced by battery created from the combination of zinc with copper wires.

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5
Q

what did Matteucci do?

A
  1. he connected electric circuit to an injured muscle tissue and connected the injured muscle to an non-injured tissue.
  2. he observed that both muscles contracted despite that injured contracted first.
  3. he determined that excitable tissues can sense and generate electricity.
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6
Q

what is the purpose of Hodgkin and Huxley experiment?

A

they tried to determine the relative permeability of ions at different points in the action potential by using Cole’s voltage clamp to measure membrane conductance during the action potential.

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7
Q

what are the H&H observations?

A
  1. hyperpolarization does not cause any channels to open, so there is no measurable current.
  2. depolarizing activates voltage-sensitive ion channels, resulting in a measurable current.
  3. step depolarizations reveal two current components: an transient inward current and a delayed outward current
  4. they determined that the early transient current is due to sodium.
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