Action Potential is
Correct Answer: Threshold stimulus is required
Description: All-or-Nothing Principle: Once an action potential has been elicited at any point on the membrane of a normal fiber, the depolarization process travels over the entire membrane if conditions are right, but it does not travel at all if conditions are not right. This principle is called the all-or-nothing principle, and it applies to all normal excitable tissues.The threshold for Initiation of the Action Potential: An action potential will not occur until the initial rise in membrane potential is great enough to create the positive feedback. This occurs when the number of sodium ions entering the fiber becomes greater than the number of potassium ions leaving the fiber. A sudden rise in membrane potential of 15 to 30 millivolts is usually required.Ref: Guyton; 13th edition; Chapter 5; Membrane Potentials and Action Potentials
Category:
Physiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now