Animals excrete nitrogenous waste in many forms. In this article, we shall examine ammonotelic organisms.
The process of excreting nitrogenous waste within the sort of ammonia is termed ammonotelic. The phenomena is recognized as Ammonotelism.
Most aquatic animals like Birds, amphibians, reptiles including fishes, some terrestrial invertebrates, larvae, and mammals including humans excrete urea acid as waste.
Ammonia, which is very water-soluble and which forms ammonia water (NH4 OH) directly injures cells by the alkaline caustic action. Therefore, the excretion of ammonia requires large amounts of acid . Some part of the uric acid is oxidized furthermore to form allantoic acid and allantoin.
Note: Allantoate or hydration product of allantoin is excreted by theTeleost fish. Allantoate is hydrolyzed into glyoxylate and urea in most amphibians and fishes. Creatine is made within the liver from amino acids. The resultant creatinine is generated from creatine.
Excretion
Almost all animals possess a particular mechanism of getting rid of the waste substances formed in their body during metabolic activities. Carbon dioxide, water, urea, uric acid, ammonia, etc. are some of the waste substances that could be harmful if they remain in the body. Besides metabolic wastes, excess salt (eg. Sodium from food), water and even certain excess vitamins got to be eliminated. Certain medicines, including antibiotics are faraway from the blood into the urine.
Excretion can be defined as the removal of all harmful, unwanted products (especially nitrogenous wastes) from the body. The excretory system is majorly associated with the removal of wastes that are nitrogenous. Urea is regarded as the primary nitrogenous waste produced in our body. It is made by the breakdown of surplus amino acids and nucleic acids in the liver. Blood transports urea to the kidneys for filtration and removal within the sort of urine.
Importance of Excretion
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Excretion is important for the elimination of nitrogenous wastes formed during the metabolism of proteins (amino acids) and nucleic acids.
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For elimination of excess salts like common salt (NaCl), vitamins, bile pigments (from the breakdown of old RBCs)
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The removal of excess water or its retention just in case of shortage. This helps to take care of the specified quantity of water – osmoregulation within the body.
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Category |
Product Formed |
Solubility in water |
Examples |
|
Ammonotelic |
Ammonia (highly toxic) |
Highly-soluble, therefore needs high level of water for its excretion |
Freshwater aquatic animals e.g. bony fish, Amoeba, etc. |
|
Ureotelic |
Urea (less toxic) |
Less soluble, thus needs less water for excretion |
Man, dog etc, marine fishes are the mammals and amphibians like frog and toad |
|
Uricotelic |
Uric acid (least toxic) |
Insoluble solids or semi-solid. Needs very little water just to ozee out the uric acid |
Birds, reptiles, and insects. |
Importance of Osmoregulators and Osmocomformers
Osmoregulation may be a process that regulates the pressure of fluids and electrolyte balance in organisms. In animals, this process is caused by osmoreceptors, which may detect changes in pressure. Humans and most other warm-blooded organisms have osmoreceptors within the hypothalamus. Besides the brain, osmoregulators also are found within the kidneys.
Different organisms exhibit different types of osmoregulation. Fish, Bacteria, Plants, Animals and even Humans undergo osmoregulation processes.
There are Two Types of Osmoregulation, Namely
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Osmoconformers and
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Osmoregulators.
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Osmoconformers can be defined as the organisms that attempt to match the osmolarity of their body with their surroundings. In other words, these organisms maintain an equivalent pressure inside the body as outside water. They conform either through active or passive means. Most marine invertebrates like starfish, jellyfish and lobsters are osmoconformers.
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Osmoregulators are a kind of organisms that actively regulate their pressure , independent of the encompassing environment. Many vertebrates, including humans, are osmoregulatory. Most seafood are considered to be osmoregulatory too.