constrictions

Constrings or constrictions refer to the act or result of making something narrower or tighter. In physiology, constriction commonly describes the narrowing of a passage within the body caused by muscle contraction or external pressure. Vasoconstriction is the narrowing of blood vessels due to smooth muscle contraction, which increases vascular resistance and can regulate blood flow and pressure. Bronchoconstriction narrows airways in the lungs and can occur in reflexive responses or disease states. Other internal constrictions include pyloric constriction or urethral and esophageal constrictions, which can affect digestion, urination, or swallowing. Chronic constrictions may form strictures or stenoses, often from scar tissue, inflammation, or tumors.

In engineering and physics, a constriction is a region where a conduit or channel narrows, altering fluid or gas flow. Constrictions influence velocity, pressure, and resistance; design considerations often use the continuity equation and related principles to predict performance. Constrictions can be intentional (nozzles, venturis) or problematic (leaks, blockages).

In broader terms, constrictions can describe bottlenecks or choke points in systems such as transportation networks, supply chains, or communication pathways, where limited capacity or flow leads to delays or inefficiencies.

Causes of constriction vary and may include muscle activity, inflammation, scar formation, external compression, or deliberate design. Treatments or interventions depend on context and aim to relieve, regulate, or compensate for the narrowed passage. See also: vasoconstriction, stenosis, choke point, bottleneck.