Nerve Impulse (Leaving Cert Biology): Flashcards

Movement of ions across neuron membrane

Inside negative, outside positive

Minimum stimulus required to start a nerve impulse

Impulse size unaffected by stimulus size (if above threshold)

Number of neurons stimulated & frequency of impulses

Inside becomes positive, outside becomes negative

Time for nerve cell to recover before next impulse

Increases speed; impulse jumps between nodes of Ranvier

Greater diameter = faster impulse

Where two neurons come into close contact

Tiny gap between pre-synaptic and post-synaptic neurons

Noradrenaline and dopamine

Broken down by enzymes or reabsorbed by pre-synaptic neuron

Protein receptors on cell membrane

Ensures impulses travel in one direction only