Left atrium

Synonym: Atrium

definition

The heart has two atria, the right atrium and the left atrium.
The atria are the respective ventricle (Ventricle) upstream and can be assigned to different blood circulation systems:

• The right atrium is part of the "small" circulation (pulmonary circulation)
• The left atrium is part of the "great" circulation (body circulation)

Left atrium illustration

1. Right atrial -
   Atrium dextrum
2. Right ventricle -
   Ventriculus dexter
3. Left atrium -
   Atrium sinistrum
4. Left ventricle -
   Ventriculus sinister
5. Aortic arch - Arcus aortae
6. Superior vena cava -
   Superior vena cava
7. Lower vena cava -
   Inferior vena cava
8. Pulmonary artery trunk -
   Pulmonary trunk
9. Left pulmonary veins -
   Venae pulmonales sinastrae
10. Right pulmonary veins -
    Venae pulmonales dextrae
11. Mitral valve - Valva mitralis
12. Tricuspid valve -
    Tricuspid valva
13. Chamber partition -
    Interventricular septum
14. Aortic valve - Valva aortae
15. Papillary muscle -
    Papillary muscle

You can find an overview of all Dr-Gumpert images at: medical illustrations

Left atrial anatomy

The atria are, so to speak, the "entrance hall" of the heart:

in the right atrium the deoxygenated blood collects from the Veinsto find out about the right ventricle in the lung to be pumped. There it is again enriched with oxygen.

The left atrium (Atrium sinistrum) is upstream of the left ventricle and is therefore part of the great circulation (Body circulation).
The blood, freshly saturated with oxygen, escapes from the lungs the pulmonary veins (Venae pulmonales) in the left atrium.

Here it will be in the Relaxation phase of the heart that diastole, collected until it is in the Tension phase (Systole) via the left wing flap (the Mitral valve) in the left ventricle flows.
From here the oxygen-rich blood gets through the aorta distributed in the body.

Function of the left atrium

The right atrium receives the deoxygenated blood from the Body circulation and directs it - via the tricuspid valve - into the right ventricle further. From there the blood gets into the Pulmonary circulation transported where it "loaded" with oxygen becomes.
Then it passes over four pulmonary veins in the left atrium, from which it - via the mitral valve - into the left ventricle is transported.
From there, the oxygen-rich blood is used to supply the body to the Body circulation pumped.
The atria help fill the ventricles with blood by contraction. However, there are other mechanisms that have a greater share in the chamber filling.

Clinical Aspects

The Atrial septal defect makes about 10% of congenital heart defects out. There is also a connection after the birth (Shunt) between the left and right atrium. Whether such a defect to the person concerned complaints makes, depends on how big this connection is, because the larger it is, the more blood can flow back and forth between the two atria:

• In the case of minor defects, there are often no symptoms at all until adulthood,
• while larger defects already lead to complaints such as Palpitations (Palpitations), shortness of breath during physical activity (Exertional dyspnea) and Reduction in performance can come.

In pronounced cases it comes from the strong Volume loading of the Pulmonary vessels to a pulmonary hypertension (high blood pressure in the Pulmonary vessels) with their grave consequences.