Q.Name any two disorders of the human circulatory system mentioned in this chapter.

Circulatory Disorders – A First Look

Think of your circulatory system as a closed loop of pipes and a pump. The pump is the heart, the pipes are blood vessels, and the fluid is blood carrying oxygen and nutrients. A disorder in this system is anything that disrupts the smooth, efficient flow of blood — either because the pump weakens, the pipes get clogged, the pressure inside them goes wrong, or the heart muscle itself doesn't get enough fuel.

The four conditions you've listed — hypertension, coronary artery disease, angina pectoris, and heart failure — are among the most common ways this system breaks down. They are deeply connected, often one leads to another.

Hypertension (High Blood Pressure)

Intuition: Blood pressure is the force blood exerts against the walls of your arteries. Imagine blowing air into a balloon — the tighter the balloon, the harder you have to blow. Hypertension means the arteries are too tight (constricted) or too stiff, so the heart has to pump much harder to push blood through. Over years, this extra strain damages both the heart and the vessel walls.

Precise statement: Hypertension is a chronic medical condition where the arterial blood pressure is persistently elevated. It is typically defined as a systolic pressure ≥ 140 mm Hg and/or a diastolic pressure ≥ 90 mm Hg, measured on multiple occasions. Most cases (≈90%) are primary (essential) hypertension — no single identifiable cause, but linked to genetics, diet (high salt), obesity, and stress. The rest is secondary hypertension, caused by another disease (e.g., kidney disease, hormonal disorders).

Coronary Artery Disease (CAD)

Intuition: The heart is a muscle that works non-stop. Like any muscle, it needs its own blood supply — delivered by the coronary arteries. CAD is when these arteries get narrowed or blocked by a buildup of fatty deposits called atherosclerotic plaques (atherosclerosis). It's like rust or sludge building up inside a narrow pipe — less blood gets through, so the heart muscle gets less oxygen.

Precise statement: Coronary artery disease is a condition in which the coronary arteries (the vessels supplying oxygenated blood to the heart muscle) become narrowed or occluded due to atherosclerosis. This reduces myocardial blood flow, especially during increased demand (exercise, stress). CAD is the most common type of heart disease and the leading cause of heart attacks.

Angina Pectoris

Intuition: When the heart muscle doesn't get enough oxygen (because of narrowed coronary arteries), it sends a pain signal — like a cramp in a leg muscle when you run too hard. That chest pain or discomfort is angina. It's a warning sign, not a heart attack (yet). The pain typically comes on with exertion and goes away with rest.

Precise statement: Angina pectoris is a clinical syndrome of chest pain or discomfort caused by transient myocardial ischemia (inadequate oxygen supply to the heart muscle) — usually due to coronary artery disease. It is not permanent cell death; the muscle is "starved" but still alive. There are two main types:

Heart Failure

Intuition: Heart failure does not mean the heart has stopped. It means the pump is failing — it can't pump enough blood to meet the body's needs. Blood backs up (congestion) in the lungs or the body, causing breathlessness and swelling. Think of a weak pump that can't keep the water circulating; water pools in the pipes. …