Anatomy study note · Thorax

Left atrium

The chamber that receives oxygenated blood from the four pulmonary veins and passes it through the mitral valve into the left ventricle. It forms most of the base (posterior surface) of the heart.

Key points

• Receives 4 pulmonary veins (no valves).
• Forms the base of the heart.
• Oesophagus directly behind → barium swallow shows enlargement.
• Left atrium: absorbs the pulmonary veins (1 → 4 openings).
• Atria secrete ANP → lowers blood pressure.
• Endocardium / myocardium / epicardium.

The full note in the atlas also covers

Features · Histology · Development · Clinical notes

Sign in free to see it on the 3D model, read the full note and practise questions on it.

Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 5, PDF pp. 614, 660
• Inderbir Singh’s Human Embryology, ch. 15, PDF pp. 232–233
• BRS Cell Biology & Histology, 7th ed., ch. 11, PDF pp. 195–196; ch. 8, PDF pp. 145–146

More from the thorax

• Left coronary artery
• Left ventricle
• Levatores costarum
• Lung
• Lymph nodes of the thoracic wall
• Main and lobar bronchi
• Mediastinal and tracheobronchial lymph nodes
• Mitral valve
• Pulmonary trunk
• Pulmonary valve
• Pulmonary veins
• Ribs

Privacy policy · Designed by DATXOC LLC.