IB Biology: C2.2-Nerve Impulses as Action Potentials

Front

What is an action potential?

Back

An action potential is the sudden, rapid reversal of the potential difference across the axonal membrane from -70mV to +30mV. It is also known as a nerve impulse.

Front

Why are nerve impulses considered electrical?

Back

Nerve impulses are electrical because they involve the movement of positively charged ions.

Front

How is a stimulus processed in the nervous system?

Back

A stimulus is picked up by a sensory receptor and transferred to the dendrites of a sensory neuron. The impulses then travel from the dendrites to the cell body, and from the cell body to the axon and the terminals.

Front

What is the role of action potentials in nerve fibres?

Back

Nerve impulses are action potentials that are propagated along nerve fibres.

Front

How is an action potential generated?

Back

An action potential is generated when the resting membrane potential of a neuron rises from -70 mV to +30 mV.

Front

What is depolarisation?

Back

Depolarisation is the sudden change in membrane potential across the inner and outer membrane from -70 mV to +30 mV. It is also called an action potential.

Front

What is repolarisation?

Back

Repolarisation is the restoration of a membrane potential following depolarisation, restoring it back to -70 mV from +30 mV.