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.
Reproduction in Echidna. A female echidna possesses a pouch in the body where she lays an egg and it takes almost 10 days for the egg to hatch. After hatching, a very small sized baby echidna comes out of the egg. The baby is so small that it needs to spend three more months with mother in the pouch, and it is one of the prominent egg laying mammals facts. Their mother feeds them with the breast milk. Since female echidna does not have nipples, it is a little problematic for the baby to suck milk.