, 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.
2. The United States nearly went to war over Louisiana. Under a 1795 treaty with Spain, U.S. merchants and farmers could send their goods down the Mississippi River and store them in New Orleans without paying export duties. For many Americans, this so-called right of deposit was important enough that talk of war began proliferating when it was revoked in October 1802.