BlogNCERTImportant Topic Of Biology: Excretory Products

Important Topic Of Biology: Excretory Products

All living things detoxify their bodies and other toxic or excessive organisms that live on earth. The removal of nitrogenous wastes produced during metabolism in the human body is called excretion. Usually, excretion means the release of nitrogenous substances such as urea ammonia uric acid, etc. Ammonia is released by other organisms called ammonotelic such as aquatic animals. Urea is released by other living organisms called ureotelic as terrestrial animals. Although uric acid is released by other organisms called uricotelic such as reptiles. Of all the pollutants, urea is the least toxic and ammonia is the most dangerous.

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    All living things on earth remove waste products from their bodies and other wastes in various ways. Excretion is an important process that takes place in all living things, including plants, animals, birds, insects, and unique organisms.

    Excretion is a physiological process of removing metabolic waste from the body. Excretory products include amino acids, urea, uric acid, carbon dioxide, water, and ammonia.

    Some Molluscs and Echinoderm detoxify the body in the form of amino acids. Ammonia is a major waste product for animals, found in proteins found in the food we eat. It is a highly toxic nitrogenous waste and is released by the distribution of many aquatic and aquatic animals and aquatic animals.

    Mammals emit nitrogenous wastes such as urea. It is less toxic and does not melt easily in water. Birds and reptiles emit nitrogenous wastes, such as uric acid.

    Excretory Organs In Human

    The human excretory system comprises the following excretory organs:

    • A pair of kidneys
    • A pair of ureters
    • Urinary Bladder
    • Urethra


    The main organ that expels human waste to other mammals is a pair of kidney beans with a brownish-red color.

    • It is the excretory and homeostatic organ of mesodermal origin.
    • It is located between the thoracic spine and the lumbar vertebra. Its weight is 140 grams.
    • There are two parts of the kidneys. Cortex and medulla are external and internal components respectively.
    • Each kid is made up of about 1,30,0000 kidney tubes called nephrons.
    • The unit of operation and structure of the kidneys is considered Nephron. There is a hammer on the inner side called the hilum at each end through which the ureters, blood vessels, and nerves enter.
    • There is a cup-shaped structure throughout the nephron called Bowman’s capsule.
    • The glomerulus is composed of tiny blood vessels found in the Bowman capsule composed of two types of arterioles.

    Afferent arteriole: Takes blood from glomerulus.

    Efferent arteriole: Blood extracted from the glomerulus.

    1. The process of filtering fluid from the bowman capsule cavity is called ultrafiltration.
    2. The main function of the kidneys is to purify the blood plasma i.e. to remove unwanted nitrogenous substances by urination.
    3. Kidney blood supply occurs in large quantities compared to other organs.
    4. At the kidney rate, 125 ml of blood per minute is filtered which is 180 litres per day.
    5. In it, 1.45 urine is produced daily, which is then drawn back by nephron cells and mixed with blood.
    • Ureter

    A white and tiny tube comes out of each hilum of each eye known as the ureter. These tubes are about 28 cm long. Both ureters open separately in the bladder but are placed close to carrying urine in the bladder.

    • Urine Bladder

    Another is a sack-like structure made of muscles that remove urine. This pear-shaped organ stores urine until urine is excreted from the body.

    • The urethra

    The neck of one of the urine leads to a tube-like structure called the urethra. It also helps with urination. It is usually shorter for women compared to men.

    • Ammonia

    The extra amino acids are released by many animals as these are the first impurities in the metabolic metabolism of proteins. These are reduced to their keto groups used in catabolism to produce ATP groups and ammonia released in other ways.

    • Urea

    In the body, urea can live for a short time as it does not dissolve in water and is less toxic.

    • Uric Acid

    They are almost insoluble in water and their crystals are non-toxic. They can stay longer in the body.

    • Urine

    Urine is an aqueous solution where 95% is water. Other nutrients are urea, uric acid, chloride, sodium, potassium, organic and inorganic potassium. The color of the urine is light yellow due to the presence of urochromes in it. Urochrome is made up of hemoglobin. Urine contains acid of 6 pH.

    Other Excretory organs of the Human Body

    • Skin: Oils and sweat glands in the skin respectively produce sebum and sweat.
    • Liver: The liver cells play a key role in excretion by converting large amounts of amino acids and blood ammonia into urea.
    • Lungs: The lungs release two types of carbon dioxide and water vapor. Extraction of other substances such as garlic, onions, and other varieties in which part of the vapour is excreted through the lungs.


    With Excretory products and their elimination, we have to urinate.

    Urine is made up of three main processes: glomerular filtration, absorption, and excretion. A nephron is an active unit of the kidneys. Blood filtering is the first stage of urine production.

    Glomerular filtration is the process of removing waste from the glomerulus. In all, Kidneys filter about 1100-1200 cc of blood every minute. Each ventricle of the heart pumps about one-fifth of the blood 24 hours a minute. The glomerular capillary blood pressure creates a filter of blood in all three layers, which is the endothelium of the glomerular blood vessels. Bowman’s epithelial capsule cells, known as podocytes, are designed in such a way that they leave behind a few minutes known as Slit holes or filtration slits. These filters filter the blood very efficiently. There is a membrane in which almost all plasma content, with the exception of plasma elements, is contained. Protein goes through Bowman’s capsule lumen.

    PCT (Proximal Convoluted Tubule): Simple cuboidal cells rank PCT.

    The brush is a borderline epithelium, which develops an extra surface for re-absorption. Almost all the basic nutrients are present, as is the case with 70-80% of electrolytes. This component absorbs both salt and water. PCT also helps maintain health. body fluids ’pH and ionic balance by selective extraction by introducing hydrogen ions, ammonia, and potassium ions to the HCO3 filtrate- absorption is the process by which HCO3 is absorbed.

    Henle’s Loop: In the ascending part of Henle’s Loop, re-installation is minimal. On the other hand, this region is important for high water conservation. This activity allows for the production of urine that is more concentrated than blood, which limits the amount of water needed for survival.

    Distal Convoluted Tubule (DCT): The ascending leg is made waterproof but automatically allows for the transfer of active or inactive electrolytes. As a result, it decreases the concentration as the concentrated filtrate rises. Electrolytes travel through the medullary fluid, which purifies the fluid. Conditional absorption of Na + from Distal Convoluted Tubule (DCT) . Return is possible with DCO HCO3and selective hydrogen and potassium ion secretion NH3 to maintain blood pH and sodium-potassium balance.


    With Excretory Products and their elimination, Mammals can form highly concentrated urine. Henle loop and vasa recta are essential for this. The flow of filtrate on Henle’s two-loop limbs on opposite sides creates a current counter. The blood flows in the opposite direction to the two organs of the vasa recta. The proximity of the Henle’s loop and the vasa recta and countercurrent between you helps to keep the osmolarity rising towards the internal medullary interstitium. NaCl and urea are the main causes of this gradient. The ascending leg carries NaCl.

    The ascending part of the vasa recta returns NaCl to the interstitium. Small amounts of urea enter the ascending part of a small part of Henle’s loop and are then returned to the interstitium by the collecting tubule. The counter-current mechanism is the chemical transport described above which is facilitated by the specific arrangement of Henle’s loop and vasa recta.

    Also read: Important Topic Of Biology: Microbodies


    Q. What are the functions of the excretory system? What are the functions of tubules?

    Ans: Excretory system functions

    • Body fluids are filtered and water is collected.
    • Immerse the waste in products and remove it from body fluids.
    • Some substances are returned to the body fluids as needed for homeostasis.
    • Disposal of feces or waste from the body.

    Tubules functions

    • A large amount of water is reabsorbed by collecting a tube to make urine concentrate.
    • Maintaining the electrolyte balance of body fluids potassium and hydrogen ion is controlled by distal convoluted tubules.
    • Lowering the Henle Loop leg draws water to make the filtrate concentrated.

    Q. Describe the process of urination?

    Ans: Mechanism of urine concentration (Countercurrent mechanism of urine concentration).

    • Both humans and animals produce hypertonic urine.
    • A countercurrent multiplier system is used to make urine hypertonic.
    • This process takes place in the Henle loop and in the vasa recta. It mainly consists of two ions namely Sodium (Na +) and Chlorine (Cl-).
    • Urine is isotonic in the proximal convoluted tubule.
    • Henle’s loop has a sloping limb that can dive into the water. The fluid in the surrounding tissue is hypertonic.
    • Thus, both ions are incorporated and water is released from the organ down through the transport process.
    • Eventually, the filtrate becomes hypertonic in the lower limb.
    What other organs excrete excrement besides the main ones in the human body?

    Apart from the urinary organs we have many organs that we can count. The first is the skin known as the sweat glands and oils found on our skin. The second is the lungs that secrete two types of gaseous substances known as water vapor and carbon dioxide. This is the release of a few substances such as onions, garlic, or other such species where part of the vapor is found to be excreted by the lungs. The last one is bold. Liver cells play a vital role in the digestive system, with the help of the conversion of extra ammonia and ammonia acids into the bloodstream within the area.

    What is the main waste disposal system?

    Well-known water-producing products are famous for their chemical reactions that are the cause of contaminated products. The list includes uric acid, salt, urea, water, and carbon dioxide. In these waste products, if one of them accumulates in the body to a certain extent, it may begin to harm the body. Here comes the role of the digestive organs as they are helpful in removing these impurities from the body. Moreover, the whole process is really important in maintaining the entire balance of our bodies.

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