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 Mesoamerican people of central Mexico in the 14th, 15th and 16th century. They were a civilization with a rich mythology and cultural heritage. Their capital was Tenochtitlan on the shore of Lake Texcoco â the site of modern-day Mexico City. In Nahuatl, the native language of the Aztecs, Aztec means someone who comes from AztlÃ¡n, a mythical place in northern Mexico. However, the Aztec referred to themselves as Mexica or Tenochca.