Nerve Action

Nerve Action Overview

• Nerve action refers to the process within the nervous system where information is transmitted across the body through nerve cells or neurons.
• Neurons transmit messages in the form of electrical signals called nerve impulses or action potentials.
• These action potentials are triggered when a threshold is reached - often due to a stimulus from the environment or other parts of the body.

Neuron Structure

• Neurons have three main components: the cell body (including the nucleus), dendrites, and the axon.
• The cell body, or soma, is the neuron’s main part and contains the nucleus, responsible for maintaining the cell and producing new neurons.
• Dendrites are branch-like structures that receive signals from other neurons and conduct them towards the cell body.
• The axon is a long, slender projection of the neuron that transmits signals away from the cell body towards other neurons or effectors like muscles.

How Nerve Action Works

• Resting potential is the state of a neuron when it’s not transmitting a signal. It has an electrical charge of about -70mV because the inside of the neuron is slightly less positive than the outside.
• If a stimulus is large enough, it can trigger an action potential. This reverses the charge of the neuron (depolarisation), making the inside positive and the outside negative.
• The depolarisation spreads along the neuron as a wave, allowing the signal to travel from the dendrites, through the cell body, and down the axon.
• After depolarisation, the neuron undergoes repolarisation. The inside of the neuron becomes negative again, returning to its resting potential.
• During the refractory period, the neuron is unable to transmit another action potential, ensuring the signal only travels in one direction.

Synapse and Neurotransmitters

• Neurons communicate with each other at junctions known as synapses.
• The neuron transmitting the signal is the presynaptic neuron, and the one receiving the signal is the postsynaptic neuron.
• The signal is passed across the synaptic cleft (gap) using chemicals called neurotransmitters.
• The electrical impulse triggers the release of neurotransmitters, which cross the synapse and bind to receptors on the postsynaptic neuron. This can either trigger or inhibit a new action potential in the postsynaptic neuron.
• Neurotransmitters not taken up by the postsynaptic neuron are usually broken down by enzymes or reabsorbed in a process known as reuptake.

Importance in Health and Social Care

• Understanding nerve action is vital for understanding how sensory information is processed, making it relevant for health and social care practices.
• Many conditions, like Parkinson’s and Alzheimer’s disease, involve disruption of nerve action.
• Furthermore, many treatments also target nerve action and synapses, such as antidepressants that affect the uptake of neurotransmitters.
• Therefore, understanding these concepts allows better support for individuals and can contribute to more effective care routines.