Nerve Impulse (Leaving Cert Biology): Flashcards

Movement of ions across neuron membrane

Minimum stimulus to start a nerve impulse

No effect

Impulse size unaffected by stimulus size (above threshold)

No. of neurons stimulated & frequency of impulses

Inside positive, outside negative

Time needed to recover before sending another impulse

Increases speed via jumping between nodes of Ranvier

Greater diameter = faster impulse

Where two neurons come into close contact

Tiny gap between two neurons in a synapse

Noradrenaline, dopamine

Broken down by enzymes OR reabsorbed by pre-synaptic neuron

Ensures impulses travel in one direction only

Needed for ionic changes during impulse