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.
These organisms use oxygen in respiration, similar to organisms on land. Fish and crustaceans obtain oxygen for respiration through their gills, while plant life and phytoplankton require dissolved oxygen for respiration when there is no light for photosynthesis 4.