Reflex arc
The route a reflex takes: from sensory neurons, through one or more relay cells, to the motor neurons that move a muscle.
See it in a lesson
Related terms
- Looming neurons
- Nerve cells behind the fly’s eyes that fire when something grows quickly in view, like a swatter coming closer. Scientists call them LC4 and LPLC2.
- Giant fiber
- A very thick nerve cell that runs from the brain down into the nerve cord. It carries the fly’s fastest escape signal. A fly has two, one on each side.
- Nerve cord
- The fly’s version of a spinal cord: a bundle of nerve cells in its chest that controls the legs and wings.
- Jump neurons
- Motor neurons that make the jump muscles of the middle legs contract, so the fly springs into the air.
- Sensory neuron
- A neuron that picks up something from the world, such as light or a smell, and reports it to the brain.
- Motor neuron
- A neuron that carries a command out to a muscle and makes it contract.
- Electrical synapse
- A direct channel between two neurons that passes a signal with almost no delay. The map behind the lessons records chemical synapses only.