what is the exact meaning of the excertory system?how does it differ in animals and human beings?what are the processes involved in the animal excretory system and human excretory system?give some applications on excretory system in plants and animals?some information on excretory system?with examples
The excretory system is the system of an organism's body that performs the function of excretion, the bodily process of discharging wastes. The Excretory system is responsible for the elimination of wastes produced by homeostasis.
Excretion in animals: Many unicellular organisms like Amoeba throw out their wastes by diffusion from their body surface. Protozoan’s have no organs for excretion. As they live in an aquatic habitat, their wastes are eliminated by diffusion through the plasma membrane.
Simple multicellular organisms like Hydra throw out solid waste matter through their mouth. Higher multicellular organisms have well-defined specialized excretory organs. These organs could be simple tubular structures as in flatworms and leech.
The excretory organs of insects (e.g., grasshopper, cockroach and housefly) are also tubular. They remove nitrogenous wastes from the body fluid and help in maintaining the water balance in the body.
In vertebrates, the main organs of excretion and maintenance of water balance are the kidneys.
Excretion in human beings: Although the kidneys are the main organs of excretion, the skin, lungs and liver also help in excretion.
Skin:
Our skin has sweat glands, through which we excrete small amounts of water, urea and salts.
Liver:
The liver excretes bile, which contains bile pigments. These are produced by the breakdown of old RBCs in the liver. As hemoglobin breaks down, its iron is retained, while the pigment (haem) is excreted with the bile.
Lungs.
The lungs help in getting rid of carbon dioxide, formed as a result of cellular respiration, through exhalation.
Excretion in plants: Compared to animals, plants do not have a well-developed excretory system to throw out nitrogenous waste materials. This is because of the differences in their physiology. Therefore, plants use different strategies for excretion.
The gaseous waste materials produced during respiration (carbon dioxide) and photosynthesis (oxygen) diffuse out through stomata in the leaves and through lenticels in other parts of the plant. Excess water evaporates mostly from stomata and also from the outer surface of the stem, fruits, etc., throughout the day. This process of getting rid of excess water is called transpiration.
Excretion in animals:
Many unicellular organisms like Amoeba throw out their wastes by diffusion from their body surface. Protozoan’s have no organs for excretion. As they live in an aquatic habitat, their wastes are eliminated by diffusion through the plasma membrane.
Simple multicellular organisms like Hydra throw out solid waste matter through their mouth. Higher multicellular organisms have well-defined specialized excretory organs. These organs could be simple tubular structures as in flatworms and leech.
The excretory organs of insects (e.g., grasshopper, cockroach and housefly) are also tubular. They remove nitrogenous wastes from the body fluid and help in maintaining the water balance in the body.
In vertebrates, the main organs of excretion and maintenance of water balance are the kidneys.
Excretion in human beings:Although the kidneys are the main organs of excretion, the skin, lungs and liver also help in excretion.
Skin:
Our skin has sweat glands, through which we excrete small amounts of water, urea and salts.
Liver:
The liver excretes bile, which contains bile pigments. These are produced by the breakdown of old RBCs in the liver. As hemoglobin breaks down, its iron is retained, while the pigment (haem) is excreted with the bile.
Lungs.
Excretion in plants:
Compared to animals, plants do not have a well-developed excretory system to throw out nitrogenous waste materials. This is because of the differences in their physiology. Therefore, plants use different strategies for excretion.
The gaseous waste materials produced during respiration (carbon dioxide) and photosynthesis (oxygen) diffuse out through stomata in the leaves and through lenticels in other parts of the plant. Excess water evaporates mostly from stomata and also from the outer surface of the stem, fruits, etc., throughout the day. This process of getting rid of excess water is called transpiration.
