Excretory Products and their Elimination for NEET UG
The kidneys filter about 180 litres of fluid a day and return almost all of it, keeping just the waste. See how a nephron does it and how hormones fine-tune urine.
BiologyClass 1177 MCQs2 lessons12 flashcards3 memory tricks
Practise Excretory Products and their Elimination free
What you'll learn
- Nitrogenous wastes and the nephron
Compare ammonotelic, ureotelic and uricotelic animals, and trace urine formation in a nephron. - Regulation of kidney function
Explain how ADH, the RAAS and ANF control water and salt balance.
Memory tricks
Ammonotelic: bony fish, aquatic amphibians (lots of water). Ureotelic: mammals, frogs, marine fish. Uricotelic: birds, reptiles, insects, land snails (paste saves water).
Bowman's capsule → PCT → loop of Henle → DCT → collecting duct.
Antidiuretic hormone makes the DCT and collecting duct reabsorb more water, so urine is concentrated. Alcohol suppresses ADH, causing frequent urination.
Try 3 NEET-style questions
Q1. Sweat secreted by sweat glands mainly helps in
- cooling the body
- removing large amounts of urea
- digestion
- storing water
Show answer
Answer: (1) cooling the body
Sweat's main function is cooling; it removes small amounts of urea and salts.
Q2. Renal calculi are
- inflammation of the glomeruli of the kidney
- build-up of urea in the blood after kidney failure
- glucose appearing in the urine of diabetics
- stones of crystallised salts such as oxalates
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Answer: (4) stones of crystallised salts such as oxalates
Renal calculi are stones or insoluble masses of crystallised salts, such as oxalates, formed in the kidney.
Q3. The proximal convoluted tubule (PCT) is lined by
- stratified squamous epithelium
- ciliated columnar epithelium
- transitional epithelium
- simple cuboidal brush border epithelium
Show answer
Answer: (4) simple cuboidal brush border epithelium
The PCT is lined by simple cuboidal brush border epithelium, which increases the surface area for reabsorption.
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