, Physiologist. 1  In four chambered avian and mammalian hearts, the two upper chambers are known as the atria. The atria are believed to act as primer pumps which boost the end diastolic volume (the volume at the end of ventricular filling) just before contraction of the ventricles.
Disunion follows the Civil War as it unfolded. New Orleans was the jewel of the Confederacy. In addition to being the Southâs largest city, it boasted considerable industry that produced ironclads, munitions and uniforms, among other items. More important, it controlled access to the Mississippi River from the Gulf of Mexico.
From 1820 to 1870, the Irish and Germans made New Orleans one of the main immigrant ports in the nation, second only to New York and far ahead of Boston, Philadelphia or Baltimore. New Orleans also was the first city in America to host a significant settlement of Italians, Greeks, Croatians and Filipinos.