dendrite

A dendrite is one of the thin, branching arms that sprout from a nerve cell (neuron) and act as its listening antennas. Picture a tree in winter: the trunk is the main body of the neuron, and the bare, twiggy branches reaching out in every direction are the dendrites. Their job is to catch incoming messages from other neurons, the way a satellite dish gathers signals from the air.

Each dendrite is covered with thousands of tiny contact points where signals from neighboring cells arrive, often landing on little bumps called spines. When a message lands, it nudges the electrical charge inside the dendrite up or down. All these small nudges flow toward the cell body and get added together; if the combined push is strong enough, the neuron fires off its own signal to the next cell. Because a single neuron can grow a dense, sprawling thicket of dendrites, it can listen to many thousands of other neurons at once, which is part of why the brain can weave together so much information.