Experiments Flashcards
1
Q
what is Bernstein’s Membrane Hypothesis?
A
- asymmetric gradient of ions inside and outside cells
- resting membrane potential more permeable to K+ ions
- action potential due to transient increase in permeability to all ions
2
Q
what is Bernstein’s predictions?
A
- action potential should be accompanied by increased membrane conductance.
- voltage should approach 0mV at peak of action potential
3
Q
what did Galvani do?
A
- He attached electric circuit to the nervous system of frogs.
- He believed that the observed muscle twitch upon completion of electric circuit indicated that animals’ tissues could generate electricity.
4
Q
what did Volta do?
A
- he disagreed with Galvani.
2. he argued that the current was produced by battery created from the combination of zinc with copper wires.
5
Q
what did Matteucci do?
A
- he connected electric circuit to an injured muscle tissue and connected the injured muscle to an non-injured tissue.
- he observed that both muscles contracted despite that injured contracted first.
- he determined that excitable tissues can sense and generate electricity.
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.
7
Q
what are the H&H observations?
A
- hyperpolarization does not cause any channels to open, so there is no measurable current.
- depolarizing activates voltage-sensitive ion channels, resulting in a measurable current.
- step depolarizations reveal two current components: an transient inward current and a delayed outward current
- they determined that the early transient current is due to sodium.