RBSE Class 11 Biology Notes Chapter 19 Excretory Products and their Elimination

These comprehensive RBSE Class 11 Biology Notes Chapter 19 Excretory Products and their Elimination will give a brief overview of all the concepts.

RBSE Class 11 Biology Chapter 19 Notes Excretory Products and their Elimination

→ Excretion in the elimination of waste products (especially nitrogen containing products produced during metabolism) from the body of an organism.

→ Waste products are unwanted toxic byproducts which are removed to maintain homeostasis and protect the body from their toxicity.

→ Nitrogenous waste products excreted by animals are mostly ammonia, urea, uric acid, amino acid creatinine etc.

→ Depending upon the major nitrogen excretory products, animals are aminotelic, ammonotelic, ureotelic and uricotelic.

→ Kidneys are the primary or major excretory organs of vertebrates.

 

→ Urine is the primary or major excretory product,

→ Liver also perform a major function in excretory system by forming urea from ammonia released during deamination of amino acids.

→ Green glands are the excretory organs of crustaceans.

→ Renette cells are the excretory organs of nematodes.

→ Nephron is the structural and functional unit of kidney which has two portions-glomerulus and renal tubules.

→ Glomerulus is a tuft of capillaries formed from afferent arterioles, fine branches of renal artery.

→ The renal tubule starts with Bowriian’s capsule and is further differentiated into a PCT, Henle’s loop (H.L.).

→ The DCT of many nephrons joins to a common collecting duct many of which ultimately open into the renal pelvis through the medullary pyramids.

→ Urine formation involves three main processes i.e., ultrafiltration, 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 121 mL filtrate in the Bowman’s capsule/minute (GFP),

→ JGA, a specialised portion of nephron plays a significant role in the regulation of GFR.

→ PCT is the major site of reabsorption and selective secretion.

→ DCT and collecting ducts allows extensive reabsorption of water and certain electrolytes which helps in osmoregulation.

→ A counter current mechanism operates between the two limbs of Henle’s loop and those of vasa recta.

→ DCT and collecting ducts concentrate the filtrate about four times i.e., from 300 m osm/L to 1200 m osm/L.

→ Urine is stored in urinary bladder till a voluntary signal from CNS carries out it releases through urethra (micturition).

→ Skin, lungs and liver also play the role in excretion.

→ Excretion: The process of removal of excretory wastes from the body.

→ Osmoregulation: Maintenance of Osmotic concentration inside the body despite the change in external surrounding.

→ Homeostasis Maintenance of equilibrium between the organism and external environment.

→ Ammonotelic: The animals which excrete ammonia are called ammonotelic.

→ Aminotelic: The animals which excrete amino acid are called aminotelic animals.

→ Ureotelic: The animals which excrete urea are called ureotelic animals.

→ Uricotelic: The animals which excrete uric acid called uricotelic animals.

→ Flame cells: These are excretory organs of platyhelminthes.

→ Nephridia: These are the excretory organs of annelids.

→ Renette cells: Excretory organs of nematoda.

→ Green glands (Antennat glands): Excretory organs of crustaceans.

→ Nephron: Structural and functional unit of kidney.

→ Cortical Nephron: Small nephrons of which major part lies in the cortex.

→ Juxta Medullary Nehpron: Large sized nephrons of which major part lies in the medulla.

→ Bowman's Capsule: It is blind double walled cup shaped structure of nephron.

→ Glomerulus: The tuft of capillaries in the Bowman’s capsule.

→ Malpighian body: The glomerulus, connective tissues and Bowman’s capsule together called Malpighian body or Malpighian capsule or renal capsule.

→ Henle's loop: ‘U’ shaped part of nephron which has descending and ascending limbs.

→ Glomerular filtration rate (GFR): The rate of filtration of blood by glomerulus is called GFR.

→ Juxtaglomerular apparatus: It is a special sensitive region formed by cellular modifications in the distal convoluted tubules and the afferent arteriole at the location of their contact.

→ Micturition: The action of urinating.

→ Micturition reflax: The neural mechanism causing micturition is called micturition reflax.

→ Urochrome: A pigment which impart a specific colour to urine.

→ Uremia: Presence of excess amount of urea in the blood.

→ Diabetes Mellitus: Excess of sugar level (glucose) in blood.

→ Diabetes insipidus: A condition of intense thirst and heavy urination.

→ Protemiria: Excess of protein level in urine.

→ Albuminuria: Presence of albumin in urine.

→ Ketonuria: Presence of ketone bodies in urine.

→ Haematurea: Presnece of blood or blood cells in urine.

→ Diuresis: Rate of passing out of urine becomes high due to very dilute urine.

→ Haemoglobinourea: Presnece of haemoglobin in urine.