Labeled Structures and NEET Points

1. Superior Vena Cava (SVC) — Returns deoxygenated blood from upper body to right atrium. SAN is located at its junction with right atrium.

2. Right Atrium — Receives deoxygenated blood from SVC and IVC. Houses the SAN (pacemaker) in its upper wall.

3. Tricuspid Valve — Three-cusped right AV valve. Opens during diastole to allow right atrial blood into right ventricle. Closes during right ventricular systole.

4. Right Ventricle — Pumps deoxygenated blood into pulmonary circulation at ~25 mmHg. Thinner wall than left ventricle.

5. Pulmonary Semilunar Valve — Guards exit of right ventricle into pulmonary artery. Opens during right ventricular systole.

6. Pulmonary Artery — Carries DEOXYGENATED blood to lungs (exception to artery rule). Note: there are two branches — left and right pulmonary arteries.

7. Pulmonary Veins — Carry OXYGENATED blood from lungs to left atrium (exception to vein rule). Four pulmonary veins (two per lung).

8. Left Atrium — Receives oxygenated blood from pulmonary veins. Thinnest-walled chamber.

9. Bicuspid (Mitral) Valve — Two-cusped left AV valve. Guards left atrioventricular opening.

10. Left Ventricle — Thickest wall (10-15 mm). Pumps oxygenated blood into systemic circulation at ~120 mmHg. Contains aortic semilunar valve at exit.

11. Aorta — Largest artery. Carries oxygenated blood into systemic circulation. Coronary arteries arise from aorta just above the aortic valve.

12. Inferior Vena Cava (IVC) — Returns deoxygenated blood from lower body to right atrium.

13. Interventricular Septum — Separates right and left ventricles. Bundle of His runs through it.

14. Interatrial Septum — Separates right and left atria. AVN is near its lower portion.