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2 Vertebrate excretory systems 3 References |
Two major types of osmoregulation are osmoconformers and osmoregulators.
Osmoconformers are animals that allow their body fluid concentration to vary with the environment. An example are marine fish. By drinking in sea water, and actively excreting salt out from the gills, the fish will gain salt as it produces an isotonic urine. Omoregulators are more common in the animal kingdom. Osmoregulators actively control salt concentrations despite the salt concentrations in the environment. An example are freshwater fish. The gills actively uptake salt from the environment. Water will diffuse into the fish where the fish will excrete a very hypotonic urine to expel all the excess water.
Kidneys play a very large role in human osmoregulation. Kidneys regulate the amount of water in urine waste. With the help of naturally producing hormones such as antidiuretic hormone, aldosterone, and angiotensin II, the human body can increase permeability of the collecting ducts in the kidney to reabsorb water and prevent it from being excreted.
A major way animals have evolved to osmoregulate is by controlling the amount of water excreted through the excretory system.
Ammonia is a toxic by-product of protein metabolism and is generally converted to less toxic substances after it is produced then excreted; mammals convert ammonia to urea while birds and reptiles form uric acid to be excreted with other wastes via their cloacas.
Four processes occur:
Forms of osmoregulation
Vertebrate excretory systems
Waste products of nitrogen metabolism
How osmoregulation is achieved in vertebrates
References