How do neurones transmit nerve impulses?

Neurones transmit nerve impulses through a process called action potential, involving electrical and chemical signals.

Neurones, or nerve cells, are specialised cells that transmit nerve impulses. This process is fundamental to the functioning of the nervous system. The transmission of these impulses is a complex process involving both electrical and chemical signals. It begins with the generation of an electrical signal, known as an action potential, in the cell body of the neurone.

The action potential is generated when the neurone is stimulated, causing a rapid change in voltage across the cell membrane. This change in voltage is due to the movement of ions, specifically sodium and potassium, across the membrane. Initially, the inside of the neurone is negatively charged compared to the outside. However, when the neurone is stimulated, sodium channels in the membrane open, allowing positively charged sodium ions to rush into the cell. This influx of positive charge causes the inside of the neurone to become positively charged, creating the action potential.

Once the action potential is generated, it travels along the length of the neurone, from the cell body to the axon terminals. This is achieved through a process known as propagation. The action potential triggers the opening of more sodium channels further along the neurone, causing the action potential to move forward. At the same time, potassium channels open to allow potassium ions to leave the cell, restoring the negative charge inside the neurone. This process is repeated along the length of the neurone, allowing the action potential to travel.

When the action potential reaches the axon terminals, it triggers the release of chemical messengers, known as neurotransmitters, into the synapse (the gap between neurones). These neurotransmitters bind to receptors on the next neurone, stimulating it and allowing the nerve impulse to continue. This complex process allows neurones to transmit nerve impulses quickly and efficiently, enabling the nervous system to function.