In its classic definition, by FranÃ§ois-Louis Ganshof (1944), feudalism describes a set of reciprocal legal and military obligations among the warrior nobility revolving around the three key concepts of lords, vassals and fiefs.
The exact cause of intracardiac echogenic foci remains unclear; however, they appear to be caused by small deposits of calcium in the papillary muscle of the fetal heart.
Pheochromocytoma is another endocrine cause of hypertension. The classic symptoms include headache, diaphoresis, palpitations, and paroxysmal hypertension. The syndrome can vary depending on the types of catecholamines being produced, the amount and frequency of their release into the circulation, and other factors.