Four primary regions are the brainstem, the cerebellum, the cerebrum, and the cerebral cortex. Each brain region is responsible for a variety of functions, and injury to any of these regions impairs specific functions.
Cellular respiration is a pathway that organisms use to generate energy. Oxygen is required and is used to break down nutrients, like glucose sugar. The nutrients are broken down to generate ATP (energy) and carbon dioxide and water (waste). Organisms from all kingdoms of life can use cellular respiration including bacteria, archaea, plants, protists, animals, and fungi.
This process happens for all kinds of living creatures. Mammals experience it in the lungs, fish experience it in the gills, earthworms experience it in their skin and amoebas experience it in their cell surface. There are two types of respiration. The first one is called aerobic respiration. This is when food is broken down to provide energy to the living organism, although it shouldn't be confused with digestion. Aerobic respiration creates ATP, a source of energy, from the breakdown of glucose and creates carbon dioxide.