Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
             Period  
The reversal of the 
resting 
potential across the 
cell 
surface 
membrane of a neuron 
or muscle cell, so that 
the inside becomes 
positively 
charged 
compared with the 
outside. 
Returning 
the 
potential 
difference 
across the cell surface 
membrane of a neuron 
or muscle cell to 
normal following the 
depolarisation of an 
action potential. 
The critical potential 
difference across the 
cell 
surface 
membrane of 
a sensor receptor or 
neuron which must be 
reached 
before 
an 
action 
potential 
is 
initiated.  
It is the decrease in 
negative 
transmembrane 
potential 
that 
is 
necessary to initiate 
an action potential 
(impulse). 
 
1. Absolute: 
Immediately 
after 
a 
stimulus 
has 
initiated 
an 
action 
potential, 
a 
nerve 
is 
unable, for a 
time, 
to 
respond 
to 
another 
stimulus 
regardless of 
its strength 
 
2. Relative: after 
the 
absolute 
refractory 
period where a 
new 
impulse 
can 
be 
initiated 
but 
only 
by 
a 
stronger- than-
normal 
stimulus. 
 
 
 
                       
Impulse Propagation:  
• 
The spread of this impulse differs depending on whether a nerve is myelinated or not. 
 
● After initiation of an action potential by a stimulus —> impulse must move along the 
surface of the axon. 
● Energy for impulse propagation is derived from the nerve membrane in the following 
manner:  
1. The stimulus disrupts the resting equilibrium of the nerve membrane.  
2. Transmembrane potential is reversed:  
● Interior: negative —> positive. 
● Exterior: positive —> negative.  
3. Producing local currents that begin to flow between the depolarized segment and the 
adjacent resting area. 
 
● These local currents flow from positive to negative, extending for several 
millimeters along the nerve membrane. 
4. As a result of this current flow:  
● The interior of adjacent area —> becomes less negative.  
● Exterior of adjacent area —> becomes less positive.  
5. The transmembrane potential is decreased by 15 mV from the resting potential resulting 
in:  
● A firing threshold.  
● Rapid depolarization.  
6. The newly depolarized segment sets up local currents in adjacent resting membrane, 
and the entire process starts again. 
7. Conditions in the segment that has just depolarized return to normal —> after the 
absolute and relative refractory periods. Because of this, the wave of depolarization can 
spread in only one direction. Backward (retrograde) movement is prevented by the 
unexcitable, refractory segment (Fig. 1.11A–C) 
 
 
 
 
Unmyelinated nerves  
Myelinated nerves  
Long cylinder with:  
● High-resistance cell membrane. 
● Low-resistance 
intracellular 
and 
extracellular media. 
Producing:  
● A rapid decrease in the density of 
current within a short distance of the 
depolarised segment.  
In areas:  
● Immediately 
adjacent 
to 
this 
depolarized segment —> local current 
flow may be adequate to initiate 
depolarization. 
● Farther away —> it will be inadequate 
to achieve a firing threshold. 
The

            Quiz: