What are impulses that are sent down a neuron?

Answer 1

These impulses are called Nerve impulse. Nerve impulse is wave of electrochemical change tha travels along the length of neuron.

Electrical potentail of neuron when it is in unstimulated condition is -70 millivolts.

In this state outside the membrane of neuron, concentration of positive ions is more than the inside of membrane. Inside the membrane potassium ions are more than sodium ions while outside the membrane sodium ions are more than the potassium ions present there.

This balance is maintained by sodium-potassium pumps through which three sodium ions move outside and two potassium ions move inside the membrane at a time. During this activity ATPase (enzyme) breaks down the ATP into ADP and phosphate then energy is released.

When a neuron is stimulated, stimulus causes its membrane to depolirized (sodium ions move inside and potassium ions move outside the membrane). The adjacent parts of membrane are also affected by this depolarization. The change travels along the neuron while the prior parts of membrane return to their original state.