Students can go through AP Inter 2nd Year Zoology Notes Lesson 2(b) Excretory Products and their Elimination will help students in revising the entire concepts quickly.
AP Inter 2nd Year Zoology Notes Lesson 2(b) Excretory Products and their Elimination
→ Excretion is the elimination of nitrogen and other waste materials from body.
→ Animals cannot eliminate free nitrogen but can eliminate it in the form of nitrogenous end products.
→ The elimination of ammonia as the chief nitrogenous waste material is called ammonotelism and such animals are called ammonotelic animals.
→ The elimination of urea as principal nitrogenous waste .material is called ureotelism and animals which excrete urea are called ureotelic animals.
→ The elimination of uric acid as the chief nitrogenous waste material is called uricotelism and uric acid excreting animals are called uricotelic animals.
→ The organ which responsible for the elimination of metabolic wastes are called excretory organs.
→ Human excretory system consists of a pair of kidneys, a pair of ureters, a urinary bladder and urethra.
→ Kidneys are the chief excretory organs in humans.
→ Each kidney has nearly one million nephrons.
→ Nephrons are the structural and functional units of kidney.
→ One average 1100-1200 ml of blood is filtered by the kidney per minute.
→ The amount of filtrate formed by both the.kidneys per minute is called Glomerular Alteration rate.
→ ADH facilitates the reabsorption of water from the DCT and collecting duct of nephron, there by preventing diuresis.
→ Glomerular filtration rate in a healthy individual is 125 ml/minute, 99% of which is reabsorbed by the renal tubules.
→ An adult human excretes, on an average 1 to 1.5 litres of urine per day, on average 25-30 gm of urea is excreted per day.
→ In addition to kidneys, lungs, liver and skin also help in the elimination of excretory wastes.
→ The presence of excess amount of urea in the blood known as uremia.
→ The process of passing out urine is called micturition.
→ The process of blood filtration by dialyser is called hemodialysis.
→ Excretion is the elimination of nitrogenous waste material like ammonia, urea, uric acid.
→ Human excretory system consists of
- a pair of kidneys
- a pair of ureters
- urinary bladder
- urethra.
→ Kidneys are main excretory organs.
→ Kidneys act as water balancing organs.
→ The body takes this advantage of water balancing system and eliminates the waste products along with water.
→ In the human kidney, the projections of the cortex that separate the renal pyramids are called columns of Bertin. [IIT]
→ The first step in the formation of urine is the ‘filtration’ of blood from glomerulus into the lumen of Bowman’s capsule is called Glpmeular filtration [IPE]
→ Renin is produced in kidney and Rennin is produced in stomach. [IPE]
→ Removal of proximal convoluted tubule from the nephron will result in more concentrated urine. [NEET-2015]
→ Human urine is usually acidic because hydrogen ions are actively secreted into the flitrate. [NEET-2015]
→ The part of nephron involved in active reabsorption of sodium is distal convoluted tubule. [NEET-2015]
→ The ascending limb of loop of Henle is impemeable to water. [NEET-2017]
→ Formation of concentrated urine is due to ‘maintaining of hyper molarity towards inner medullary intestitium in the kidneys’. [NEET-2019]
→ Use of an artificial kidney during haemodialysis may result in (i) reduced absorption of calcium ions from gastro-intestinal tract (ii) reduced RBC production. [NEET-2019]
→ Reabsorption of Na+ and water from renal tubules due to aldosterone help in the prevention of diuresis. [NEET-2020]