Neuron

Neurons are nervous system cells that process and transmit information. They communicate with each other through chemicals called neurotransmitters.

Basic Structure

While there are many different types of neurons, most have the same basic structure.

• Cell Body (soma): The core of the cell that holds the nucleus and other organelles.
• Dendrites: Tree-like branches that receive information from other neurons.
  • Spines: These are tiny bumps on the dendrites where neurotransmitters connect to the cell.
• Axon: A long 'tail' coming off the cell body. This is where the neuron sends information to other cells.
  • Synaptic Terminals: Endpoints of the axon where the neuron releases neurotransmitters.

Neurons that cross between different brain regions often have myelin sheaths. Myelin is a fatty substance that coats an axon. It provides insulation so the neuron's electrical signal can travel longer distances without degrading.

Communication

Neural communication works through a process of electrical and chemical signaling. As an example, let's imagine a signal traveling through three neurons labeled A, B, and C.

1. Neuron A releases neurotransmitters out of its axon terminal. The chemicals float into the gap between Neurons A and B, called the synapse.
2. The neurotransmitters latch onto the receptors on Neuron B's dendrites, much like a key into a lock.
3. The ions from these neurotransmitters raise or lower the electric charge within Neuron B. Raising the electrical charge is called excitation. Lowering the cell's electric charge is called inhibition.
4. When Neuron B's electrical charge raises to a certain level, the cell will spike. This event is also called an action potential.
5. An electrical signal travels down Neuron B's axon to the terminal. The cell releases its neurotransmitter load into the synapse, where they will connect with Neuron C.

It's important to remember that a single neuron is often getting dozens or even hundreds of inputs at one time. These signals can combine or cancel each other out. Ultimately, it's the total result of all these inputs that determines whether a neuron will spike or not.