Neurons and Synapses

Sensory neurons (PNS)

Neurons that form sense organs and convert energy into electrical impulses. Have a long dendrites to receive sensory information from receptors, allow it to form connections with multiple receptor cells.

Neuron

The basic unit of the nervous system.

Dendrites

Nerve endings branching off the cell body to receive information.

Enzymes

Biological molecules that break down neurotransmitters.

Postsynaptic neuron

The neuron receiving the neurotransmitter signal.

Presynaptic neuron

The neuron releasing neurotransmitters at the synapse.

Interneurons (CNS)

Neurons that transfer messages within the central nervous system. Lots of short dendrites and axons.

Motor neurons (PNS)

Neurons that transmit messages from the CNS to effector organs like muscles. Small dendrites but long axons to send information to far effector cells.

Synapses

Small gaps between neurons where messages cross chemically via neurotransmitters.

Sensory Neurons

Neurons sensitive to stimuli inside and outside the body, sending information to the CNS.

Cell body (soma)

Part of the neuron containing the nucleus.

Axon

Long structure carrying nerve impulses away from the cell body.

Nerve Impulses

Electrical signals traveling through neurons from one part of the body to another.

Synapse

The junction between two neurons where nerve impulses cross.

Nerve impulse

The electrical signal that travels through neurons.

Motor Neurons

Neurons that carry signals away from the CNS to cause movement in muscles.

Interneurons

Neurons that link sensory and motor neurons for communication.

Myelin sheath

Insulating layer around the axon for rapid impulse transmission.

Axon Terminal

Transfers messages from one nerve cell to another's dendrites.

Neurotransmitters

Chemicals that transmit signals across synapses between neurons.

Impulse

The signal transmitted through neurons.