Interstitials

Interstitials refer to spaces, structures, or elements that exist in the gaps between principal components. In anatomy and physiology, the interstitial space refers to the tissue space around cells, filled with interstitial fluid, part of the extracellular fluid that exchanges substances with blood plasma through capillary walls. The interstitium includes connective tissue and extracellular matrix. Fluid balance in these spaces is important for nutrient delivery and waste removal; accumulation of fluid, known as interstitial edema, can reflect injury or disease. Interstitial compartments also play a role in imaging and pathology, where changes in interstitial pressure or fibrosis alter tissue function.

In materials science, interstitials are atoms that occupy interstitial sites in a crystal lattice, smaller than the host atoms. This creates an interstitial solid solution and can markedly change mechanical properties, including hardness, strength, and diffusion. Common examples include carbon in iron (forming steels), and nitrogen in titanium or nickel alloys. The presence of interstitial atoms can distort the lattice and impede dislocation motion, contributing to work hardening or embrittlement under certain conditions.

In digital media, interstitials are advertisements or messages that appear between content pages or during navigation, often as full-screen overlays or interstitial pages. They aim to capture user attention during transitions but can be intrusive, leading platforms to regulate their frequency, duration, and placement to balance revenue with user experience.