Cytoplasm. The cytoplasm is the part of the cell which does all the work. Different cells do different jobs, however whatever the job is it will require energy in the form of a chemical called ATP. This energy containing chemical is produced by tiny organelles in the cell called mitochondria. Muscle cells contain two very special chemicals called actin and myosin.
Definition of TREPHINATION. : an act or instance of perforating the skull with a surgical instrument. ADVERTISEMENT.efinition of TREPHINATION. : an act or instance of perforating the skull with a surgical instrument. ADVERTISEMENT.
The Good Old Days. Trephination (or trepanation) is an operation performed since Stone Age times (though far less frequently these days) in which a circular section of the skull is carved away, leaving a hole in the skull.odern Day Trephination. Even trephination gets its 15 minutes of fame these days. A TV documentary show (20/20) aired a segment on February 10, 2000, about the modern practice of trepanation.