postganglionära

Postganglionära refers to the neurons located after the ganglion in the autonomic nervous system. The autonomic nervous system regulates involuntary bodily functions and is divided into the sympathetic and parasympathetic branches. In both divisions, nerve signals travel from the central nervous system along a two-neuron chain to reach the target organ.

The first neuron in this pathway is called the preganglionic neuron. Its axon, the preganglionic fiber, extends to an autonomic ganglion, where it synapses with the second neuron. This second neuron is the postganglionic neuron. Its axon, known as the postganglionic fiber, then travels from the ganglion to the effector organ, such as a gland, smooth muscle, or the heart.

A key distinction between preganglionic and postganglionic fibers is the neurotransmitter they release at their terminals. Preganglionic fibers typically release acetylcholine. In contrast, most postganglionic fibers of the sympathetic nervous system release norepinephrine, while postganglionic fibers of the parasympathetic system release acetylcholine. This difference is fundamental to the opposing effects these two systems have on the body.

Therefore, "postganglionära" describes the final neural link that directly influences the activity of involuntary muscles and glands, translating central commands into peripheral physiological changes.