Heart LO6

6.) Identify the unique structures of the left atrium.

The left atrium receives the pulmonary veins from the lungs.

Auricle (appendage): muscular pouch that is located in the superior, left border (often overlapping the root of the pulmonary trunk)

  • Internally, has pectinate muscles
    • Only area of the internal L. atrium with pectinate muscle (the rest is mostly smooth-walled)

L. atrioventricular (mitral) valve orifice

  • The L. AV valve is located between the L. atrium and L. ventricle

Interatrial septum

  • Wall between the R. and L. atrium

Semilunar depression: a small depression in the interatrial septum that represents the floor of the fossa ovalis