Question

Referring to a typical strength-duration curve, which of the following are true? (circle all that apply)

a. The rheobase current is the minimum current required to elicit a response
b. The rheobase current is equal to twice the chronaxie
c. Chronaxie is the duration of stimulation at twice the rheobase current
d. Chronaxie is the minimum duration required to elicit a response at maximum current
e. The strength-duration curve plots the threshold current as a function of pulse duration
f. The strength-duration curve plots the magnitude of cardiac contraction as a function of ECG recording duration

Answer 1

a) The minimum current that can elicit an action potential the pulse duration goes to infinity is called the Rheobase current. This current is the minimal amount of intensity needed to obtain. Hence it is true. b) It is the minimum time required for an electric current double the strength of the rheobase. Hence it is true. c) The duration of a stimulus pulse that uses a current that is double the Rheobase current. Therefore the Chronaxie is the duration with the double rheobase current hence it is true. d) The minimum current that can elicit an action potential a response at maximum current Hence it is true The strength duration curve is a plot of the threshold current I vs pulse duration (d) required to stimulate excitable tissue. It is true. f) ECG is the process of producing an Electrocardiogram a, recording- a graph of voltage and vs time. The overall magnitude of the heart's electrical depolarization is captured at each moment throughout the cardiac cycle. Hence it is true