Hypertension
உயர் இரத்த அழுத்தம்
The heart is a pump, not a pressure vessel. When systemic arterial pressure exceeds 140/90 mmHg, you are no longer regulating homeostasis; you are damaging the vascular endothelium. Stop confusing 'stress' with 'hypertension'.
The idea
Hypertension is defined as blood pressure consistently higher than the normal 120/80 mmHg. A reading of 140/90 mmHg or higher is clinically classified as hypertension. This condition indicates increased resistance to blood flow, forcing the heart to work harder to maintain systemic circulation.
Why it matters
It is a pathological condition resulting from factors like narrowed vessels or lifestyle, which puts excessive strain on the heart and vital organs.
NEET lens
NEET focuses on the specific threshold values: 120/80 is normal, 140/90 is hypertensive. Do not confuse systolic and diastolic pressures. Memorize these figures; they are frequently tested in 'Body Fluids and Circulation' matching questions.
Clinical significance
Chronic hypertension leads to vital organ damage, specifically targeting the kidneys, brain, and the heart itself. It accelerates atherosclerosis, increasing the risk of myocardial infarction and cerebrovascular accidents. The heart muscle undergoes hypertrophy to compensate for the increased afterload.
Introduction
Hypertension is persistently elevated arterial blood pressure (≥140/90 mmHg), a major risk factor for heart attack, stroke, kidney failure, and other cardiovascular diseases — often asymptomatic for years.
Core concept
Normal BP: systolic <120, diastolic <80 mmHg. Hypertension: ≥140/90 mmHg. Systolic = pressure during ventricular contraction. Diastolic = pressure during ventricular relaxation. Types: Primary/Essential (90-95%): no identifiable cause. Genetic + lifestyle factors (salt intake, obesity, stress, inactivity). Secondary (5-10%): identifiable cause — renal artery stenosis, primary aldosteronism, pheochromocytoma, thyroid disorders. Complications: heart attack (increased cardiac workload → LV hypertrophy → failure). Stroke (rupture/thrombosis of cerebral vessels). Kidney damage (nephrosclerosis). Retinal damage. Aortic aneurysm.
Go deeper
Renin-Angiotensin-Aldosterone System (RAAS): key regulator of BP. Low BP/Na⁺ → kidney releases renin → converts angiotensinogen → angiotensin I → ACE (in lungs) → angiotensin II → vasoconstriction + aldosterone release (Na⁺/water retention) → BP rises. ACE inhibitors and ARBs block this system → lower BP.
From Class 10
High blood pressure, or hypertension, is often called a 'silent killer' because it has no symptoms but slowly damages blood vessels and organs.