Lymphatic vessels play are critical for fluid homeostasis, protein and lipid transport, and immunity. Lymphatic abnormalities or poor lymphatic function can result in lymphedema, which in the most severe cases result in extreme swelling and deformation of tissues. Thanks to increased awareness about lymphatic physiology, several recent studies have shown that lymphatic dysfunction may contribute to a much wider range of pathologies. The microscopic image on the left shows a rat mesenteric collecting lymphatic that was isolated and mounted on glass micropiettes. Collecting lymphatics typically display phasic contractions and tone. In conjunction with the intraluminal valves, the phasic contractions allow the vessel to work as a series of pumps. Image contributed by Jerome Breslin at the University of South Florida.