The following steps are involved in muscle contraction: (1) The sequence of events leading to contraction is initiated somewhere in the central nervous system, either as voluntary activity from the brain or as reflex activity from the spinal cord.
The average Mexican man weighs 165 pounds and stands 5 feet 4 1/2 inches tall, while the median figures for Mexican women are 151 pounds and 5 feet 2 inches, according to a study released by a group representing Mexico's clothing industry.
Gallery. 1  The summit of Pico de Orizaba, a stratovolcano on the border between Puebla and Veracruz, is the highest peak of Mexico. 2  The summit of VolcÃ¡n PopocatÃ©petl, a stratovolcano at the junction of Puebla, MÃ©xico State, and Morelos, is the second highest peak of Mexico.