Final answer:
Essential hypertension is characterized by an increased blood pressure due to genetic and lifestyle factors, with the renin-angiotensin-aldosterone system playing a key role in its pathophysiology.
Step-by-step explanation:
The basic pathophysiologic change in essential hypertension is increased blood pressure without an identifiable secondary cause. Essential hypertension is primarily caused by a combination of genetic factors and lifestyle choices, including diet, salt and alcohol consumption. It accounts for about 90% of hypertension cases. Lifestyle changes and medication are pivotal in managing this condition. A critical aspect of hypertension pathophysiology involves the renin-angiotensin-aldosterone system, where increased levels of angiotensin II cause vasoconstriction and the release of aldosterone, leading to elevated systemic blood pressure.