Cardiovascular System: Anatomy, Physiology, and Clinical Significance

The cardiovascular system comprises the heart, blood vessels (arteries, veins, capillaries), and blood. It ensures continuous delivery of oxygen, nutrients, hormones, and immune cells while removing metabolic wastes.

Core Functions

1. Transport: O₂, CO₂, nutrients, hormones, waste, heat, immune cells.
2. Regulation: Blood pressure (baroreflex, RAAS), temperature (cutaneous vasodilation/constriction), pH (bicarbonate buffer).
3. Protection: Clotting (platelets, coagulation factors), immune defense (WBCs, antibodies).

Circulatory Pathways

• Systemic circulation: Left ventricle → aorta → arteries → capillaries (exchange) → veins → vena cava → right atrium.
• Pulmonary circulation: Right ventricle → pulmonary artery → lungs (gas exchange) → pulmonary veins → left atrium.
• Coronary circulation: Supplies myocardium (RCA, LAD, LCx).

Hemodynamic Principles

• Cardiac output (CO) = HR × SV. Regulated by preload, afterload, contractility.
• Mean arterial pressure (MAP) = CO × SVR. Autoregulation in vital organs.
• Capillary exchange: Starling forces (hydrostatic vs. oncotic pressure).

Clinical Relevance

• Atherosclerosis → coronary artery disease, stroke, PAD.
• Heart failure: reduced EF (HFrEF) or preserved EF (HFpEF).
• Hypertension: major modifiable risk factor.
• Arrhythmias: AFib, VT/VF, conduction blocks.

Lifestyle for Cardiovascular Health

• 150 min/week moderate aerobic activity + resistance training.
• Mediterranean/DASH diet: fruits, vegetables, whole grains, lean protein, nuts, olive oil; limit sodium, saturated fat, added sugar.
• Smoking cessation, weight management, stress reduction, adequate sleep.
• Control BP, lipids, glucose per guidelines.