Lymphatic Physiology with a Focus on Lymph Transport: A Narrative Review

The lymphatic system plays a central role in maintaining circulatory and immune homeostasis through three classical functions: recovery of interstitial fluid and proteins, absorption of dietary lipids, and regulation of immune cell trafficking. Recent advances in microvascular physiology, including the revision of Starling’s principle, highlight the lymphatic system as the exclusive pathway for protein-rich fluid clearance from tissues. Structurally, specialized features such as flap valves in initial lymphatics, anchoring filaments, and contractile lymphangions ensure unidirectional transport and adapt to changes in tissue pressure, respiration, and skeletal muscle activity. Beyond these established roles, emerging evidence demonstrates lymphatic involvement in cholesterol metabolism, brain waste clearance via the glymphatic pathway, ocular fluid regulation, and tissue repair. Dysfunction of these mechanisms contributes not only to lymphedema but also to a broader range of conditions including neurodegenerative, cardiovascular, and oncologic diseases. For clinicians, a modern understanding of lymphatic physiology provides a foundation for recognizing the systemic implications of lymphatic dysfunction and informs both diagnostic and therapeutic strategies.