Neurons: The Body's Communication Specialists
Neurons are the specialised cells of the nervous system responsible for transmitting electrical signals throughout the body. Unlike most cells, neurons are uniquely structured to receive, process, and send information rapidly, allowing the body to detect stimuli and respond within milliseconds.
Imagine touching a hot stove , your hand pulls away almost instantly. That split-second reaction is powered by neurons firing electrical signals at high speed along dedicated pathways.
Neural signalling involves two fundamentally different types of communication:
- Electrical signalling along the length of a neuron (action potentials)
- Chemical signalling between neurons at specialised junctions called synapses
Don't assume all neural communication is electrical. Signals travel electrically along a neuron, but they cross the gap between neurons chemically using neurotransmitters.
Structure of a Neuron
A neuron has three main structural components, each with a distinct role in signal transmission:
1. Cell Body (Soma)
The control centre of the neuron. It contains the nucleus (housing genetic material) and cytoplasm with organelles including mitochondria, which supply ATP for the neuron's energy-demanding functions.
2. Dendrites
Short, branched fibres extending from the cell body. They act like antennas, receiving signals from other neurons or sensory receptors and transmitting them toward the cell body.
3. Axon
A single, elongated fibre that carries electrical impulses away from the cell body. Axons range from a few millimetres to over a metre long (e.g., the axon connecting the spinal cord to the toes).
Memory aid: Dendrites = Delivery to the cell body. Axon = Away from the cell body.
Many axons are wrapped in a myelin sheath , a fatty insulating layer that dramatically increases the speed of impulse transmission.
Don't confuse dendrites and axons. Dendrites receive signals and carry them toward the cell body; the axon transmits signals away from the cell body toward the next neuron or effector.
