1 Extrapyramidal tracts â These tracts originate in the brain stem, carrying motor fibres to the spinal cord. 2  They are responsible for the involuntary and automatic control of all musculature, such as muscle tone, balance, posture and locomotion.his article is about the descending tracts of the central nervous system. The descending tracts are the pathways by which motor signals are sent from the brain to lower motor neurones. The lower motor neurones then directly innervate muscles to produce movement.
The word oxygen comes from Greek words: oxus (acid) and gennan (generate). Oxygen comes to earth from all parts of the universe in meteorites. It is also found in minerals and plants that grow on the earth and other planets.
Antoine Lavoisier, a French chemist, also discovered oxygen in 1775, was the first to recognize it as an element, and coined its name oxygen - which comes from a Greek word that means acid-former. There is a historic dispute about who discovered oxygen. Most credit Priestly alone or Both Priestly and Scheele.xygen was discovered for the first time by a Swedish Chemist, Carl Wilhelm Scheele, in 1772. He called the gas fire air because of the brilliant sparks it produced when it â¦ came in contact with hot charcoal dust.