Final answer:
Multiple graded potentials arriving at the trigger zone can cause excitatory and inhibitory potentials to cancel each other, excitatory potentials to summate and possibly reach threshold, or inhibitory potentials to add together and decrease excitability. The correct answer is E) A, B, and C.
Step-by-step explanation:
When two or more graded potentials arrive at the trigger zone of a neuron, several things can happen:
- An excitatory and inhibitory signal can cancel each other out, a process known as synaptic inhibition.
- Two excitatory stimuli may be additive, and summation could occur, potentially leading to an action potential if the threshold is reached.
- Two inhibitory stimuli may be additive, resulting in lower excitability and thus reducing the likelihood of an action potential being generated.
Therefore, the correct answer is E) A, B, and C. All listed phenomena can occur when multiple graded potentials meet at the trigger zone, influencing whether or not the neuron will fire an action potential.