Aortic insufficiency (AI), also known as aortic regurgitation (AR), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle.
Definition of echidna. : a spiny-coated toothless burrowing nocturnal monotreme mammal (Tachyglossus aculeatus) of Australia, Tasmania, and New Guinea that has a long extensible tongue and long heavy claws and that feeds chiefly on ants; also : a related mammal (Zaglossus bruijni) of New Guinea having a longer snout and shorter spines.
Henna by Sienna. Henna is a natural dye produced from the leaves of the henna plant, a small flowering shrub (scientific name: Lawsonia inermis). The henna plant grows all over the world in hot, dry areas, from North Africa across the Middle East and throughout Southern Asia.