What distinguishes why an action potential propagates unidirectionally down an axon, rather than bidirectionally from the axon hillock during neuronal signaling?

💡 Explanation

Unidirectional propagation happens because of the absolute refractory period. Sodium channels that have just opened and inactivated proximally, remain inactivated, preventing immediate reactivation and reverse propagation; therefore, the action potential moves forward rather than backwards, ensuring signal directionality, rather than bidirectional travel.

• Why does the proteasome system become less effective at protein aggregate clearance with aging in neurons?
• Why does chronically sun-exposed skin wrinkle and sag more readily than skin protected from the sun?
• A voltage-gated sodium channel in a neuron's axon opens, initiating an action potential. Which consequence follows from a prolonged inactivation of these sodium channels during this action?
• Why does focusing on a near object cause blurring of distant objects after prolonged near work?
• Why does beta-amyloid aggregate accumulation selectively impair long-term potentiation (LTP) at hippocampal synapses?
• If a drug inhibits the hydrolysis of cGMP in retinal photoreceptors, which consequence follows for phototransduction in the eye?