In the right atrium, the auricle and anterior wall exhibit obvious muscular ridges called

In the right atrium, the auricle and anterior wall exhibit obvious muscular ridges called MUSCULI PECTINATI.

Musculi pectinati or pectinate muscles are identified as specialized intracardiac muscle. The muscular ridges are like combs. These ridges help the right atrium dilate without much walls stress during adverse loading conditions.

Molecules called lipids have long hydrocarbon chains that determine the way they act. they can be fats, oils, or hormones, and even exist in our cell membranes