NCERT Solutions for Class 11 Biology Chapter 16 Excretory Products and their Elimination
NCERT Solutions for Class 11 Biology Chapter 16 Excretory Products and their Elimination covers modes of excretion, the human excretory system (nephron structure), urine formation, and regulation of kidney function.
Overview of Topics & Subtopics (Click to Jump)
1. Modes of Excretion
Short Note:
• Ammonotelism: excretion of ammonia (mostly aquatic animals). Ureotelism: excretion of urea (e.g., mammals). Uricotelism: excretion of uric acid (e.g., birds, reptiles, insects) — conserves water.
2. Human Excretory System
Short Note:
• Consists of a pair of kidneys, ureters, urinary bladder, and urethra; each kidney is composed of functional units called nephrons (each with Bowman's capsule, glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule).
3. Urine Formation
Short Note:
• Occurs in three steps: Glomerular filtration (blood filtered at Bowman's capsule to form filtrate), Reabsorption (useful substances like glucose, amino acids, water reabsorbed back into blood, mostly at PCT), and Secretion (additional wastes/H+/K+ secreted into the filtrate at the DCT).
4. Regulation of Kidney Function
Short Note:
• Regulated by hormones like ADH (Antidiuretic Hormone/Vasopressin), which increases water reabsorption, and the Renin-Angiotensin-Aldosterone System (RAAS), which regulates blood pressure and sodium/water balance.
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