, 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.
1 Louisiana was the first of 13 states, or parts of states, to be carved out of the territory in 1812. 2  Due to slow communications, the Battle of New Orleans was fought two weeks after the Treaty of Ghent was signed on December 24, 1814, ending the War of 1812 between the United States and Great Britain. In 1803, Thomas Jefferson doubled the size of the United States by purchasing the Louisiana Territoryâ828,000 square miles of land between the Mississippi River and the Rocky Mountainsâfrom France. 2  Louisiana was the first of 13 states, or parts of states, to be carved out of the territory in 1812.