The crustacean gill has numerous roles, including osmotic/ionic control, acid-base balance, ammonia excretion, and bioaccumulation of hazardous metals

Ion transport, which forms the basis for hemolymph osmoregulation, acid-base balance, and ammonia excretion are just a few of the physiological activities that take place in the multifunctional organ known as the crustacean gill. The gill plays a significant role in the toxicology of these species since it is the place where many hazardous metals are ingested by aquatic crustaceans. This article offers a thorough understanding of the ecology, physiology, biochemistry, and molecular biology of the gill's mechanisms for controlling osmotic and ionic balance. The history of their creation is examined, along with the current theories regarding the mechanics of ion transport and the structural, biochemical, and molecular underpinnings of systemic physiology. The connection between hemolymphic acid-base control and branchial ion transport.