Image Based Question – 73757

All of the following are true about basal electrical rhythm of intestines except:

A. Tone of contraction is related to amplitude of the stimulus

B. Tone of contraction is related to frequency of stimulation

C. Frequency of contraction is 6 per minute

D. Threshold of contraction is —50 mV

Correct Answer » A Explanation

Ans: A. Tone of contraction is related to amplitude of the stimulus

(Ref Ganong 25/e p496-497, 24/e p498-499)

• Tone of contraction depends on stimulus frequency rather than amplitude.

Threshold for action potential:

• Upto 50 mV (I.e. potential required to trigger an action potential & contraction).
• One contraction in 10 seconds implies frequency is 6 contractions/minute.