Select
Image:

The primitive atria form the auricles, the rough-walled portions of the definitive atria. Incorporation of the walls of the sinus venosus on the right and the pulmonary veins on the left forms the smooth-walled portions of the definitive atria.
                     Species: Mouse 
                     Day Gestation: 15 
             Approx. Human Age: 9 weeks 
                                   View: Ventral
                   Atrial Walls
                                   40 of 42