Excretion and Osmoregulation Class 11 | Chapter 19 biology class 11 | NCERT Biology Hindi Audiobook

#ExcretionandOsmoregulationClass11
#Chapter19biologyclass11
#NCERTBiologyHindiAudiobook
#beatdneet
#उत्सर्जीउत्पादएवंनिष्कासन
#neet2023
#excretoryproductsandtheirelimination
#excretory_system
#excretionandosmoregulation
#excretion
#excretorysystem
#urea
#ammonia
#neet2022
#neet2023
#neetbiology
#neet
#ncert
#ncertaudiobook
#biologyaudiobook
#biology
#biomania
Excretion and Osmoregulation Class 11 | Chapter 19 biology class 11 | NCERT Biology Hindi Audiobook
Many nitrogen containing substances, ions, CO2, water, etc., that accumulate inthe body have to be eliminated. Nature of nitrogenous wastes formed and theirexcretion vary among animals, mainly depending on the habitat (availability ofwater). Ammonia, urea and uric acid are the major nitrogenous wastes excreted.Protonephridia, nephridia, malpighian tubules, green glands and the kidneys arethe common excretory organs in animals. They not only eliminate nitrogenous wastesbut also help in the maintenance of ionic and acid-base balance of body fluids.In humans, the excretory system consists of one pair of kidneys, a pair of ureters,a urinary bladder and a urethra. Each kidney has over a million tubular structures
called nephrons. Nephron is the functional unit of kidney and has two portions -glomerulus and renal tubule. Glomerulus is a tuft of capillaries formed from afferentarterioles, fine branches of renal artery. The renal tubule starts with a double walledBowman’s capsule and is further differentiated into a proximal convoluted tubule(PCT), Henle’s loop (HL) and distal convoluted tubule (DCT). The DCTs of manynephrons join to a common collecting duct many of which ultimately open into the
renal pelvis through the medullary pyramids. The Bowman’s capsule encloses the glomerulus to form Malpighian or renal corpuscle.
Urine formation involves three main processes, i.e., filtration, reabsorption and secretion. Filtration is a non-selective process performed by the glomerulus using the glomerular capillary blood pressure. About 1200 ml of blood is filtered by the glomerulus per minute to form 125 ml of filtrate in the Bowman’s capsule perMany nitrogen containing substances, ions, CO2, water, etc., that accumulate in the body have to be eliminated. Nature of nitrogenous wastes formed and their excretion vary among animals, mainly depending on the habitat (availability of water). Ammonia, urea and uric acid are the major nitrogenous wastes excreted.
Protonephridia, nephridia, malpighian tubules, green glands and the kidneys are the common excretory organs in animals. They not only eliminate nitrogenous wastes but also help in the maintenance of ionic and acid-base balance of body fluids.
In humans, the excretory system consists of one pair of kidneys, a pair of ureters, a urinary bladder and a urethra. Each kidney has over a million tubular structures called nephrons. Nephron is the functional unit of kidney and has two portions - glomerulus and renal tubule. Glomerulus is a tuft of capillaries formed from afferent arterioles, fine branches of renal artery. The renal tubule starts with a double walled Bowman’s capsule and is further differentiated into a proximal convoluted tubule (PCT), Henle’s loop (HL) and distal convoluted tubule (DCT). The DCTs of many nephrons join to a common collecting duct many of which ultimately open into the renal pelvis through the medullary pyramids. The Bowman’s capsule encloses the glomerulus to form Malpighian or renal corpuscle.
Urine formation involves three main processes, i.e., filtration, reabsorption and secretion. A counter current mechanism operates between the two limbs of the loop of Henle and those of vasa recta (capillary parallel to Henle’s loop). The filtrate gets concentrated as it moves down the descending limb but is diluted by the ascending limb. Electrolytes and urea are retained in the interstitium by this arrangement.
DCT and collecting duct concentrate the filtrate about four times, i.e., from 300 mOsmolL-1 to 1200 mOsmolL-1, an excellent mechanism of conservation of water. Urine is stored in the urinary bladder till a voluntary signal from CNS carries out its release through urethra, i.e., micturition. Skin, lungs and liver also assist in excretion.