The human heart is a muscular, four-chambered organ that pumps blood through the pulmonary and systemic circuits via double circulation. It is important for NEET Biology because NTA frequently tests heart anatomy, the cardiac cycle (SA node, AV node), cardiac output, and blood pressure regulation.
Right Atrium
Receives deoxygenated blood from the superior and inferior vena cava and passes it to the right ventricle through the tricuspid valve.
Left Atrium
Receives oxygenated blood from the pulmonary veins and passes it to the left ventricle through the bicuspid (mitral) valve.
Right Ventricle
Pumps deoxygenated blood to the lungs via the pulmonary artery for gas exchange.
Left Ventricle
Pumps oxygenated blood to the entire body through the aorta; has the thickest wall among all chambers.
Tricuspid Valve
Three-flapped valve between right atrium and right ventricle; prevents backflow of blood into the right atrium.
Bicuspid (Mitral) Valve
Two-flapped valve between left atrium and left ventricle; prevents backflow of blood into the left atrium.
Semilunar Valves
Half-moon shaped valves at the base of the aorta and pulmonary artery; prevent blood from flowing back into the ventricles.
Aorta
Largest artery in the body; carries oxygenated blood from the left ventricle to systemic circulation.
Pulmonary Artery
Carries deoxygenated blood from the right ventricle to the lungs; the only artery that carries deoxygenated blood.
Pulmonary Veins
Carry oxygenated blood from the lungs to the left atrium; the only veins that carry oxygenated blood.
Superior Vena Cava
Large vein that returns deoxygenated blood from the upper body (head, arms, chest) to the right atrium.
Inferior Vena Cava
Large vein that returns deoxygenated blood from the lower body (abdomen, legs) to the right atrium.
Septum
Muscular wall that separates the left and right sides of the heart, preventing mixing of oxygenated and deoxygenated blood.
Double Circulation
NTA frequently tests the concept of double circulation — pulmonary (heart → lungs → heart) and systemic (heart → body → heart). Know why it is essential for maintaining separation of oxygenated and deoxygenated blood in mammals.
Cardiac Cycle (SA node, AV node)
Expect questions on the sequence of cardiac events — SA node initiates impulse, spreads to AV node, then to Bundle of His and Purkinje fibres. Know the duration of one cardiac cycle (0.8 sec) and the phases of systole and diastole.
Cardiac Output
NTA tests the formula: Cardiac Output = Stroke Volume × Heart Rate. Normal CO is about 5 L/min. Know how exercise, autonomic nervous system, and hormones affect cardiac output.
Blood Pressure Regulation
Questions on systolic (120 mmHg) and diastolic (80 mmHg) pressure, hypertension, and the role of the medulla oblongata in regulating heart rate through sympathetic and parasympathetic nerves.
Solve previous year NEET questions on heart anatomy, blood circulation, and cardiac cycle.
View PYQs →Practice NEET-pattern questions on the circulatory system.
Practice Now →Browse all 32 chapters of NEET Biology previous year questions.
Browse All →Master heart anatomy, double circulation, cardiac cycle and blood pressure with previous year questions that match NTA's exact patterns.