ABSTRACT
This chapter looks at the osmoregulatory functions of animal. The ability to regulate water and solute concentrations is referred to as osmoregulation. It is necessary to review the concept of osmosis as this is central to the process of osmoregulation. Osmosis is an example of a colligative property. When animal cells are placed in distilled water, the cell rapidly gains water by osmosis and will eventually burst. Equally, if cells are placed in a concentrated salt solution, they will rapidly lose water by osmosis and will shrink. It is possible to classify the osmotic responses of animals into two broad categories — they are either osmoconformers or osmoregulators. Osmoconformers are animals whose body fluid concentration is exactly the same as that of the immediate environment in which they live. The osmotic and ionic conformation that the hagfish utilizes has been used as physiological evidence that vertebrates evolved in the marine environment.
