1. SINDH TEXTBOOK BORAD JAMSHORO
BIOLOGY FOR CLASS IX

2. Excretions Content Chapter #12 Class IX Excretion In Plants
Excretion In Animals
Excretory Organs In Ameoba
Excretory Organs In Planaria
Excretory Organs In Earthworm
Excretory Organs In Cockroach
Excretory Organs In Vertebrates
The Human Excretory System
Working Of Kidney
Kidney Kialysis

3. Excretion
The process, act or function of discharging or ejecting waste product of metabolism, especially from the system of an organism
Plants eliminate some waste through diffusion. During the day, excess oxygen gas produced by photosynthesis is released through the stomata. Carbon dioxide produced by respiration is normally used up during photosynthesis. At night, however, as photosynthesis slows, carbon dioxide is not used up as fast as it is produced, and it is released as a waste product. Plants also produce oxygen as a by-product of photosynthesis. The oxygen that is not used for respiration is also excreted through the stomata.

4. Plants also eliminate waste by the accumulation of waste in the vacuoles of the aging leave cells. These leaves will eventually die and fall off, removing waste in the process. This process is called abscission.
These are excretory products and may be resins, gums, latex and or other excretory products. These products maybe poisonous, however many have found use in everyday life of humans, such as latex which is used to produce gloves and clothing.

5. Excretion in Animals
   The nitrogenous waste materials produced in the animal body due to metabolic reactions are of no use to the cell. These waste materials if allowed to accumulate in the body, may become toxic. Therefore, they must be removed from the body. The process of elimination of metabolic waster products from the animal body to regulate the composition of the body fluids and tissues is called excretion.

6. Excretion in Amoeba
Amoeba is a protozoan which forms the simplest of all groups in the animal kingdom. Inspite of being unicellular it is physiologically balanced and performs all the essential processes of an animal.
Amoeba is fresh water in habitat, these by- products of dissimilation (oxidation of organic substances) are disposed off mainly by diffusion through the general surface which is the cell membrane into surrounding water.

8. Excretion in planaria
Planaria are flatworms that live in fresh water. Their excretory system consists of two tubules connected to a highly-branched duct system that leads to pores located all along the sides of the body. The filtrate is secreted through these pores. The cells in the tubules are called flame cells (or protonephridia) because they have a cluster of ciliathat looks like a flickering flame when viewed under the microscope. Flame cells function like a kidney, removing waste materials through filtration. The cilia propel waste matter down the tubules and out of the body through excretory pores that open on the body surface; cilia also draw water from the interstitial fluid, allowing for filtration. After excretion, any useful metabolites are reabsorbed by the cell. Flame cells are found in freshwater invertebrates, such as flatworms, including parasitic tapeworms and free-living planaria.

10. Excretion in Earthworm
In its moist skin by the process of diffusion. The nitrogenous earthworm carbon dioxide and nitrogenous wastes are the main waste materials. The carbon dioxide is excreted out from the body through wastes are excreted out of the body by special excretory organs called nephridia (singular nephridium).       A Nephridium is tubular coiled structure. It starts from a rounded funnel shaped structure called nephrostome. The nephrostome opens in a coiled tube called nephridial tubule which is lined with cilia. The nephridial tubule opens outside the body through a small opening called nephridiopore.      The body fluid of earthworm rich in nitrogenous wastes enters the nephridium through nephrostome and passes into nephridial tubule. In the nephridial tubule the useful substances present in fluid are absorbed. The remaining fluid containing high percentage of nitrogenous wastes is excreted out of the body through nephridiopore with the help of movements of cilia.

12. Excretion in Cockroach
The excretory organ of cockroach is the malpighian tubules. It is found at the junction of the midgut and hind gut and are about 150 in number. They are fine, yellow coloured and branched threads present in bundles. They lie freely in the haemolymph.
The distal parts of the tubules extract inorganic ions, uric acid and amino acids by active transport and water by diffusion from the surrounding haemolymph. The filtrate moves towards the ileum. In the proximal parts of the malpighian tubules water and other useful substances are reabsorbed. The remaining materials passes into the gut. More water and inorganic ions are reabsorbed in the gut. Almost solid uric acid, is finally eliminated with the faeces.

14. Excretion in Vertebrate
Excretion in Physiology is the process of elimination of metabolic wastes and other toxic substances from the body. Organs of the Excretory System
Lungs – removal of excess carbon dioxide
Liver – produces urea and uric acid as a by-product of the breakdown of proteins
Skin – removal of excess water, salt, urea and uric acid
Urinary System – kidneys filter the blood to form urine, which is excess water, salt, urea and uric acid
Functioning of the kidney
The kidney removes metabolic and liquid toxic wastes as well as excess water from the organism.