A :
current electrode
delivers current
needs a ground to complete the circuit
voltage electrode
measures / records the membrane potential
connected to amplifier ( triangle )
circuit diagram : electrical model of the paramecium's membrane
Connected in parallel between inside / outside
B :
Membrane Potential Recordings (
Three current pulses with progressively larger current steps
0.023 nA , 0.115 nA , 0.23 nA
Resting Membrane Potentail =
Also in the voltage traces
they are both depolarizing and hyperpolarizing
potassium channels ?
let 1.7 cm = 10 mV
https://docs.google.com/spreadsheets/d/1wifR-23MPgIjohKm3V95hU6fXJVN2OItsUKGZBsq34o/edit?usp=sharing
Measure initial , and peak y-values
initial =
final =
Calculate
find difference in y-values :
take approximately 63% of the value :
add this number to initial y-value :
find corresponding x-value to this calculated y-value :
i got roughly 4 centimeters between initial x value of pulse and then over to where -28 would be
200 milliseconds = 17.5 cm
so 4 centimeters :
Measure initial , and peak y-values
initial =
final =
Calculate
find difference in y-values :
take approximately 63% of the value :
add this number to initial y-value :
find corresponding x-value to this calculated y-value :
i got roughly 4 centimeters between initial x value of pulse and then over to where -21 would be
200 milliseconds = 17.5 cm
so 4 centimeters :
Measure initial , and peak y-values
initial =
final =
Calculate
find difference in y-values :
take approximately 63% of the value :
add this number to initial y-value :
find corresponding x-value to this calculated y-value :
i got roughly 4 centimeters between initial x value of pulse and then over to where -17 would be
200 milliseconds = 17.5 cm
so 4 centimeters :
human neurons have around 10-50 ? pico Farads
these Paramecium have much much higher capacitance of around 350-500 pico Farads
they all have virtually the same time constant
Capacitance is directly proportional to total surface area