How does ameba get rid of waste

The collecting tubules of many nephrons join to form the collecting duct. Collecting ducts collect urine from the nephrons and transport in the medulla of the kidney.

Formation of urine: The purpose of excretion is to filter out waste products from the blood. As this filtrate passes through the tubular parts of nephron, some useful products, such as glucose, amino acids, salts and major amount of water are selectively reabsorbed by blood capillaries surrounding the nephron. The nephrons drain the remaining liquid waste urine into the collecting duct which eventually enters a long tube, the ureter.

Human urine contains water and nitrogenous substances, most of which is urea. From the ureter, urine passes into the urinary bladder. Urine is stored in the urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra. The bladder is muscular, so it is under nervous control. As a result, we can usually control the urge to urinate. Plants use completely different strategies for excretion than those of animals.

Some of the important plant wastes and the methods by which they are removed are as follows :. The gaseous waste products are CO 2 and O 2 produced as a result of respiration and photosynthesis respectively. These gaseous wastes are removed through stomata in leaves and lenticels in stem and released in air.

Plants get rid of excess water by the process of transpiration. For other solid and liquid waste, plants use the fact that many of their tissues consist of dead cells and that they can even lose some parts such as leaves. Rubber is a significant article of plant origin which has unusual properties of elasticity, plasticity, resistance to electric currents, impermeability to water and adhesiveness.

Acacia nilotica vern. Babool , Boswelliaserrata vern. Salai , Anogeissuslatifolia vern. Pine resin is obtained from species of Pinus. Turpentine is an antiseptic solvent from paints and polishes. It is also used medicinally as anthelmintic. Resin is used in preparing writing paper, water proofing, sealing joints of pipes, soap, wheel greese, etc. Damar from Shorearobusta or Sal and related trees is employed in the manufacture of varnishes and spirit polishes.

Home Life Process Excretion Excretion Life Process of Class 10 The process of removal of toxic wastes from the body of an organism is called excretion. These are as follows: In Amoeba and other single celled animals, contractile vacuole serves the function of excretion and osmoregulation. In sponges, the waste materials diffuse out of the body through the osculum. In animals like Hydra belonging to Cnidaria , the oral opening serves as the excretory organ.

Species that possess a CV always use it, even in very hypertonic high concentration of solutes environments, since the cell tends to adjust its cytoplasm to become even more hyperosmotic hypertonic than the environment. The amount of water expelled from the cell and the rate of contraction are related to the osmolarity of the environment. In hyperosmotic environments, less water will be expelled and the contraction cycle will be longer.

The number of CVs per cell varies, depending on the species. Amoeba have one; Dictyostelium discoideum , Paramecium aurelia, and Chlamydomonas reinhardtii have two; and giant amoeba, such as Chaos carolinensis , have many. In some unicellular eukaryotic organisms e. In Paramecium , which, presumably, has the most-complex and highly-evolved CV, the vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm. After the canals fill with water, it is pumped into the vacuole.

When the vacuole is full, it expels the water through a pore in the cytoplasm that can be opened and closed. Malpighian tubules remove wastes from insects by producing urine and solid nitrogenous waste, which are then excreted from the body. Malpighian tubules line the gut of some species of arthropods, such as bees. They are usually found in pairs in the posterior regions of arthropod alimentary canals; the number of tubules varies with the species of insect.

The system of malpighian tubules consists of branching tubules, which increase their surface area, near the hemolymph a mixture of blood and interstitial fluid that is found in insects, other arthropods, and most mollusks and fat tissues.

They are lined with microvilli for reabsorption and maintenance of osmotic balance. They contain actin for support. Malpighian tubules work cooperatively with specialized glands in the wall of the rectum. Body fluids are not filtered, as in the case of nephridia. Instead, urine is produced by tubular secretion mechanisms by the cells lining the malpighian tubules that are bathed in hemolymph. Metabolic wastes, such as urea and amino acids, freely diffuse into the tubules, while ions are transported through active pump mechanisms.

The secretion of ions alters the osmotic pressure, which draws water, electrolytes, and nitrogenous waste uric acid into the tubules. Water and electrolytes are reabsorbed when these organisms are faced with low-water environments and uric acid is precipitated and excreted as a thick paste or powder.

By not dissolving wastes in water, these organisms are able to conserve water; this is especially important for life in dry environments. Malpighian tubules in bees : Malpighian tubules of insects and other terrestrial arthropods remove nitrogenous wastes and other solutes from the hemolymph.

Privacy Policy. Skip to main content. Osmotic Regulation and the Excretory System. Search for:. Excretion Systems. Learning Objectives Describe the process of handling wastes in microorganisms. Key Takeaways Key Points Contractile vacuoles protect a cell from absorbing too much water and potentially exploding by excreting excess water.

Wastes, such as ammonia, are soluble in water; they are excreted from the cell along with excess water by the contractile vacuoles. Contractile vacuoles function in a periodic cycle by expanding while collecting water and contracting to release the water.

Key Terms contractile vacuole : a vacuole that removes waste or excess water osmoregulation : the homeostatic regulation of osmotic pressure in the body in order to maintain a constant water content osmolarity : The osmotic concentration of a solution, normally expressed as osmoles of solute per litre of solution. Flame Cells of Planaria and Nephridia of Worms Flame cells and nephridia remove the waste from bodies through filtration in a manner similar to a kidney.

Learning Objectives Compare and contrast the way in which planaria and annelids handle waste products.