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.
The noun OXYGEN has 1 sense: 1. a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust.Familiarity information: OXYGEN used as a noun is very rare.Dictionary entry details. â¢ OXYGEN (noun).ypernyms (oxygen is a kind of...): chemical element; element (any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter).