Respuesta :
The two upper parts or chambers of the heart are called Atria's,
they're separated from their lower counterparts the ventricles by an interatrial septum. All the Atria's do is receive blood returning from the heart to the body.
they're separated from their lower counterparts the ventricles by an interatrial septum. All the Atria's do is receive blood returning from the heart to the body.
