EXCRETORY SYSTEM

1. EXCRETORY SYSTEM

2. Excretory System • Metabolic wastes of the chemical reactions in the cell are removed from the body. • This process is called EXCRETION.

3. Function of Excretory System • Filtration and excretion of metabolic wastes • The regulation of blood content. • The regulation of blood pH. • Homeostasis.

4. Excretory Substances • The metabolic wastes of cells are;WATER,CO2,NITROGENOUS COMPOUNDS

5. WATER and CO2 • Water and CO2 are formed by means of cellular respiration. • Water is excreted by lungs, sweating and kidneys. • CO2 is excreted only by lungs.

6. NITROGENOUS WASTES • At the end of the catobolisation of aminoacids, AMMONIA(NH3) is formed. • In some organisms, ammonia is removed fro body directly. • But in some organisms ammonia is converted to other substances such as UREA and URIC ACID.

7. AMMONIA (NH3) • Ammonia is the most toxic nitrogenous waste material. • It can soluble in water. • Organisms need large amount of water for excretion of ammonia. • Organisms need small amount of energy for formation of NH3 • Ammonia is excretory substances of freshwater organisms.

9. UREA [CO (NH2)2] • It is formed in the liver by ornithin cycle. • Urea is less toxic than ammonia. • Urea is excreted by the kidney. • Urea is the excretory substances of amphibians,mammals,fish and human. • Organisms use more energy in formation of urea than formation of ammonia. • Living things need normal amount of water.

10. URIC ACID (C5NH4O3) • Uric Acid is least toxic nitrogenous waste. • It is insoluble in water. • Uric acid is excreted by with only small amount of water. • Uric acid is the excretory substance of terrestial organisms such as INSECTS, REPTILES AND BIRDS.

12. EXCRETION IN LIVING THINGS

13. EXCRETION IN PLANTS • There is no special excretory system in plants. • The STOMA, LENTICELS, HYDATHODES are used for excretion in plants. • CO2 is excreted by stomata and lenticels. • Water is excreted by hydathodes and stomata by TRANSPIRATION.

17. excretion in invertebrates

18. Excretion in Unicellular Organisms • Excretory structure of protista is called CONTRACTILE VACUOLE. • Excess water and NH3 are pumped by contractile vacuole. • Some NH3 molecules release from unicellular organisms by diffusion.

20. In simple animals such as Spongy and hydra excretory substances are excreted by diffusions.

23. Excretion in Planaria (Flatworms) • In planaria, excess water is excreted by flame cells. • Flame cell take excess water from body. • Than water pass excretory canal. And than water is given out of the body by excretory pore. • CO2 and NH3 release from planaria by means of DIFFUSION.

25. Excretion in Earthworm • Excretory organ of earthwom is nephridium. • Nephridium is surrounded by capillaries. • It takes water, glucose, minerals and wastes from body. Than water, food and minerals are reabsorbed from nephridium canal by capillaries. • And than waste materials pass into intestine.

28. Excretion in Insects • Insects have specialized excretory tubules that called MLPIGHIAN TUBULES. • Wastes pass from blood into malpighian tubules Than malpighian tubules empty into digestive track. • Finally waste materials are excreted by anus with undigested materials.

30. GRASSHOPPER DRAGON FLY

31. excretion in VERTEBRATES

32. The excretory and reproductive system of vertebrates are interrelated and this complex is called UROGENITAL SYSTEM • The kidney is the main excretory organ of vertebrates.

33. TYPES OF KIDNEYS • There are three types of Kidneys; • Pronephros kidney • Mesonephros kidney • Metanephros kidney

34. PRONEPHROS KIDNEY • Pronephros kidney is found in the embryonic stage of fish and amphibia and in adult form of shark. • Pronephros kidneys contain many nephridia. • Nephridia have ciliary funnels that is connected to ball of capillaries or glomerulus by ciliary funnels. • Than wastes pass wolf channel for transport to the cloaca.

35. MESONEPHROS KIDNEY • Mesonephros kidney is found in embryonic stage of reptiles, birds an mammals and adutlt stage of fish and amphibia. • In mesonephros kidney, ciliary funnels are replaced with Bowman’s capsules. • A glomerulus is located in Bowman’s capsule. Waste materials pass to Bowman’s capsule from glomerulus. • Than wastes flow the wolf channel. And than they are expelled through cloaca.

36. METANEPHROS KIDNEY • Metanephros kidney is found in adult reptiles, birds, mammals and human. • Each kidney contains a millions of nephrons.

38. CLOACA • In fish, amphibians, reptiles and birds; excretory substances, unigested materials and reproductive cells are expelled through the same channel or openin that called CLOACA.

39. HUMAN EXCRETORY SYSTEM

40. PARTS OF HUMAN EXCRETORY SYSTEM • Kidneys • Ureter • Urinary bladder • Urethra

43. KIDNEY • Kidneys are bean shaped organs that filtere 180 lt. blood in a day. • Blood is come into kidney by renal artery. • Filtered blood leaves from kidney by renal vein.

44. Functions of Kidneys • They remove wastes of cellular metabolism from the blood. • They control concentration of various substances found in the body fluid.

45. Structure of Kidneys • Renal Capsule:It surrounds and protects the kidneys. • Cortex:It contains glomerulus and Bowman’s capsules. • Medulla:It is located under the cortex and has malphigian pyramids. Malphigian pyramids contains urine collecting canal and loop of henle. • Pelvis:It is innermost part of kidney. The urine is collected in pelvis.

48. NEPHRONS • They are structural unit of kidneys. • A nephron begins with a glomerulus. • Glomerulus is surrounded by a Bowman’s capsule. • Each glomerulus is formed by capillaries from a branch of renal arteriole.