Tractes

Tractes, in anatomical usage, refers to two related concepts: a bundle of nerve fibers within the central nervous system that connects regions, and a tubular organ or passageway that conveys substances through the body. The term is most often encountered in relation to neural tracts in the brain and spinal cord, but it also appears in descriptions of body systems such as the digestive or respiratory tracts.

In the nervous system, tracts are organized bundles of axons located in the brain and spinal cord. They form connections that enable communication between different regions and are typically classified as ascending (sensory) or descending (motor). Examples include the corticospinal tract, which carries motor signals from the cerebral cortex to the spinal cord, and the spinothalamic tract, which conveys pain and temperature information to the thalamus. Tracts are distinguished by their origins and destinations, and they travel within white matter as opposed to peripheral nerves, which reside in the peripheral nervous system.

Outside the central nervous system, the term tract is used for major tubular passages that transport substances or enable physiological functions. Common examples are the digestive tract (from mouth to anus), the respiratory tract (air passages from the nose or mouth to the lungs), the urinary tract, and the reproductive tract. These tracts are continuous anatomical structures rather than nerve fiber bundles and play roles in digestion, respiration, excretion, and reproduction.

Clinical relevance centers on the integrity and function of tracts. Damage to neural tracts can produce specific deficits corresponding to their connections, while disease affecting tubular tracts can disrupt transport or processing within those systems. Modern imaging and tractography techniques help map neural tracts for diagnosis, planning, and research.