Morphine, like many prescription drugs, may require larger doses for pain control when used for extended periods of time. Over time, the body can develop a tolerance for the medication and will require more medication to experience the same level of effectiveness.
By Kimberly Munro Fri, Mar 18, 2011. The first installment of our Ancient Peru series relates what archaeology has revealed about its first cities and civilizations. The expansive, culturally rich civilizations that existed in the Americas at the time of European contact came as a great surprise to the early Spanish explorers. Most notable were the Aztec empire in Central Mexico and the Incan empire in Peru, both of which controlled great expanses of land and millions of people.
The Aztecs were a Pre-Columbian Mesoamerican people of central Mexico in the 14th, 15th and 16th centuries.They called themselves Mexica (pronounced [meËÊikaÊ]).The Republic of Mexico and its capital, Mexico City, derive their names from the word Mexica. The capital of the Aztec empire was Tenochtitlan, built on a raised island in Lake Texcoco.Modern Mexico City is built on the ruins of Tenochtitlan.he Aztecs were a Pre-Columbian Mesoamerican people of central Mexico in the 14th, 15th and 16th centuries.