What role does active transport play in nerve function?

Active transport plays a crucial role in nerve function by maintaining the resting potential and propagating nerve impulses.

Active transport is a process that moves ions across cell membranes against a concentration gradient, requiring energy in the form of ATP. In the context of nerve function, active transport is primarily involved in the movement of sodium and potassium ions across the nerve cell membrane, which is crucial for maintaining the resting potential and propagating nerve impulses.

The resting potential is the electrical potential difference across the nerve cell membrane when the neuron is at rest, typically around -70 millivolts. This is maintained by the sodium-potassium pump, a type of active transport that pumps three sodium ions out of the neuron for every two potassium ions it pumps in. This creates a higher concentration of sodium ions outside the neuron and a higher concentration of potassium ions inside, resulting in a net negative charge inside the neuron.

When a nerve impulse, or action potential, is triggered, there is a rapid change in the membrane potential. Sodium channels open, allowing sodium ions to flow into the neuron down their concentration gradient, making the inside of the neuron positively charged. This is followed by the opening of potassium channels, allowing potassium ions to flow out of the neuron, restoring the negative charge inside. This sequence of events propagates along the length of the neuron as a wave of depolarisation and repolarisation, transmitting the nerve impulse.

After the nerve impulse has passed, the sodium-potassium pump re-establishes the resting potential by actively transporting sodium and potassium ions back to their original concentrations. This is essential for the neuron to be able to transmit further impulses.

In summary, active transport is vital for nerve function as it maintains the resting potential and enables the propagation of nerve impulses. Without it, our nervous system would not be able to function effectively.