DoorstepTutor (NEET, JEE, IMO, NSO, NTSE...)'s video: Excretory Products Elimination: NCERT Class 11 Biology NEET Course CBSE English MCAT

NEET UG Medical entrance: https://www.doorsteptutor.com/Exams/NEET/ NSO: https://www.doorsteptutor.com/Exams/NSO/ NTSE: https://www.doorsteptutor.com/Exams/NTSE/ NSTSE: https://www.doorsteptutor.com/Exams/NSTSE/ Exam Preparation - https://www.doorsteptutor.com/Exams/ More interesting topics subscribe at TestPrep: https://www.youtube.com/c/TestPrep NCERT, Yojana, Kurukshetra, Down to Earth, Science, Social Studies and More interesting topics subscribe at Examrace: https://www.youtube.com/c/Examrace NCERT, Yojana, Kurukshetra, Down to Earth, Science, Social Studies and More interesting topics subscribe at ExamraceHindi: https://www.youtube.com/c/ExamraceHindi For kids learning with kids videos subscribe to FunProf: https://www.youtube.com/c/FunProf Websites https://www.examrace.com https://www.doorsteptutor.com https://www.flexiprep.com https://www.examtestprep.com https://www.jobduniya.com Ammonia – bony fish, amphibians aquatic insects Urea – mammals, terrestrial amphibians, marine fishes Uric Acid – reptiles, birds, insects, land snails Nephron – glomerulus and renal tubule Glomerulus has tuft of capillaries formed by afferent arteriole Bowman’s capsule+glomerulus = renal corpuscle Tube PCT – proximal convoluted tubule DCT –distal convoluted tubule Malpighian corpuscle + PCT + DCT in cortica of kidney & loop of Henle in medulla When loop of henle is small – extend little into medulla -cortical nephrons When loop of henle is long – it is deep in medulla called juxta medullary nephron Efferent arteriole from glomerulus forms capillary network around renal tubule called peritubular capillaries – one parallel to loop of Henle is vasa recta(absent or reduced in cortical nephron) PCT: simple cuboidal brush border epithelium – increase surface area for reabsorption ; 70-80% electrolyte and water is reabsorbed – maintain pH and ionic balance by selective secretion of H+, NH3, K+ into filtrate and absorption of HCO3- Henle’s loop: reabsorption is minimum in ascending limb – high osmolarity of interstitial fluid Descending limb is permeable to water and impermeable to electrolytes - it concentrates the filtrate as it moves down Ascending limb is impermeable to water but allow transport of electrolyte actively or passively – as concentrated filtrate pass up it gets diluted due to passage of electrolytes of medullary fluid DCT: conditional reabsorption of Na+ and water , reabsorption of HCO3-, selective secretion of H, K and NH3 to maintain pH and Na-K pump balance Collecting duct – from cortex of kidney to inner parts of medulla – most water is reabsorbed to form concentrated urine; allows passage of small amount of urea into medullary interstitium to keep up osmolarity; maintain pH and ionic balance of blood by selective secretion of H+ and K+ ions Micturition – urine to urinary bladder stored for voluntary signal by CNS- stretch receptors send signal to CNS – contraction of smooth muscle and release of urine Neural mechanism is micturition reflex Urine is slightly acidic with pH6.0 25-30 gm of urea is excreted per day Glucose in urea (glycosuria) & ketones is (ketonuria) in urine – indicative of diabetes mellitus Other excretory organs Lungs: CO2 (200ml/minute) Liver secretes bilirubin, biliverdin, cholesterol, steroid, vitamin and drugs Sweat by sweat glands is water+NaCl+urea+lactic acid – cools body and removes waste Sebacous gland eliminates sterols, hydrocarbons and waxes through sebum (provides protective oily covering for skin) Also small nitrogenous waste is eliminated through saliva as well Disorders Uremia (urea in blood) – can lead to kidney failure (hemodialysis by artificial kidney) Dialysing fluid has same composition as plasma except nitrogenous waste (blood is drained by adding anti-coagulant as heparin) As nitrogenous waste is absent in dialysising fluid – substance move out of blood and clear blood – this is pumped back into vein by adding anti-heparin again For kidney failure – kidney transplant is the only correction – donor should be close relative with same blood group to provide minimum chances of rejection by immune system Renal calculi – crystals of oxalate in kidney Glomerulonephritis – inflammation of glomeruli of kidney