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.
Echidnas are monotremes, or egg-laying mammals. Covered with fur out of which dozens of sharp spines protrude, the echidna is sometimes known as the spiny anteater. Although â¦ the echidna is not at all related to anteaters, it does feed primarily on termites and ants.he echidna lays eggs, making it a monotreme, but it is also a mammal, as the young suckle mother's milk. During breeding season, the female echidna develops a pouch, where she lays and incubates her egg. The pouch is little more than a fold of skin, and even the male can develop a pouch.