What is meant by excretiaon?Explain the process of formation pf urine?
Answers
Answer:
Excretion means reducing the amount of waste material from the body
Answer:
(i) Excretion is a biological process involved in removed of Wastes from the body.
(ii) In Latin ‘Ex’ means Out, ‘Crenere’ means Shift.
(iii) A number of reactions take place during Metabolic activities. When the Carbohydrates protein and Fats are Metabolized, CO2, H2O, and Nitrogenous compounds like Ammonia, Urea, Uric Acid are produced.
(iv) If the metabolic wastes are not discharged from the body, they become Toxic and harm the body.
The process of Formation of Urine:
It has involved in four stages; They are –
(a) Glomerular Filtration: Blood flows into occur through afferent arteriole.
⇒ Filtration or Ultra-Filtration of Blood occurs in Glomerulus. This Glomerulus filtrate is known as Primary Urine.
⇒ Waste Molecules, Nutrient molecules and Water are filtrate out and Water the Bowman capsule.
(b) Tubular Reabsorption: The peritubular capillaries around PCT reabsorb all the useful component of Primary Urine such as Glucose, Amino-Acid, Vitamin C, Potassium, Calcium, Sodium, Chlorides and 75% of Water.
(c) Tubular Secretion:
⇒ It is the active secretion of waste products by Blood Capillaries into the Urinary tubule.
⇒ It ensures removal of all the waste products from Blood like Urea, Uric Acid, and Creatinine Salt ions like K+, Na+ and H+ Ions. This maintains proper concentration and pH of Urine.
(d) Concentration of Urine:
⇒ 75% of Water of Nephric filtrate is reabsorbed in the region of proximal convoluted tubule and 10% of Water passes out of filtrate through Osmosis in the area of loop of Henle.
⇒ Further concentration of Urine takes place in the area of collecting tubes in the pressure of Hormones called Vasopressin.
⇒ The hormone is secreted only when concentrated Urine is to be passed out. Hormone action maintains Osmotic concentration of Fluids.