Functional groups are defined as specific groupings of atoms or bonds which are part of a larger hydrocarbon chain. It is necessary that you are able to recognize these groups by structure and by name. The ending of the name as a suffix tells the type of compound or functional group present.
[TA] a slight constriction of the aorta immediately distal to the left subclavian artery at the point of attachment of the ductus arteriosus. Synonym(s): isthmus aortae [TA], isthmus of aorta. A constriction in the fetal aorta between the ductus arteriosus and the left subclavian artery.
Aortic stenosis (AS or AoS) is the narrowing of the exit of the left ventricle of the heart (where the aorta begins), such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time.