These MP Board Class 11th Biology Notes for Chapter 19 Excretory Products and their Elimination help students to get a brief overview of all the concepts.
MP Board Class 11th Biology Notes Chapter 19 Excretory Products and their Elimination
→ Earthworms excrete ammonia when sufficient water is available but excrete urea in drier environment.
→ Human is ureotelic, but excretes little amount of uric acid in the urine which is formed from the nucleic acids. In some persons the formation of uric acid is abnormally increased by metabolic disorders or their urinary excretion becomes defective. This raises the concentration of uric acid in the body fluids and as it is insoluble, it gets deposited in soft tissues including joints, cartilages and kidneys, such individuals consequently develop gout and kidney failure.
→ Formation of urea from ammonia takes place in the liver.
→ In mammals, camel is the best adapted animal to the dry conditions. Camel does not store water. In the problem of osmoregulation, like most desert animals, it is intimately related to the temperature regulation. In summer, camel varies its osmoregulation to a greater extent than in winter and may exhibit a morning temperature of 34°C and in afternoon maximum of 41°C. It helps to prevent sweating and thus water is conserved.
→ During day period, amphibians generally do not expel urine.
→ Animals which are able to tolerate wide range of change in osmotic concentration of the external environment are called euryhaline and those with narrow range of tolerance are called stenohaline.
→ The blood may appear in the urine in the form of R.B.Cs. or haemoglobin. First condition is called haematuria and the second haemoglobinuria.
→ Presence of large number of pus cells in the urine indicates infection in the kidney or urinary tract. A condition of pus in the urine is known as pyuria.
→ Sometimes certain substances like calcium oxalate, calcium phosphate and uric acid, etc. are crystallized and form stones in the kidney. These stones cause pain, haematuria and pyuria, sometimes urinary passage may be blocked by these stones.
→ Cystitis is the inflammation of the urinary bladder mainly involving mucosa and submucosa. It may be due to bacterial infection, chemical or mechanical injury.
→ Toad and lung fishes generally excrete ammonia but when water becomes insufficient they excrete urea.
→ After metamorphosis, tadpole larva excrete urea in place of ammonia.
→ The blood of shark fish contains urea which is responsible for osmoregulation.
→ Earthworm and lung fishes are ammonotelic animals but during shortage of water and hibernation, they become ureotelic.
→ Green glands are the excretory organs of crustaceans like prawn.
→ Malpighian tubules are the excretory organs of insects like cockroach.
→ Human and other primates are ureotelic.
→ Aldosterone is the hormone which is responsible for the controlling of the amount of sodium
and water in the body.
→ Filtration takes place in the glomerulus of nephrons.
→ Vasopressin hormone is secreted by pituitary glands which controls the amount of urine in the body.
→ Diuresis is the condition in which secretion of urine is in large quantities.
→ Diabetes insipidus is a condition in which ADH hormone is not produced and large amount of water is excreted along with urine.
→ Alkalidine and caffeine present in tea and coffee respectively, increases the amount of urine secretion.