Frank Brothers Solutions for ICSE Class 10 Biology Chapter 8 Excretory System

Solution 1:
Answer: Separation and elimination of the metabolic nitrogenous wastes from the body is called excretion. Kidneys, skin and lungs are important excretory organs.
In simple words: Excretion is how our body gets rid of harmful waste products that are made when cells work, mainly through kidneys, skin, and lungs.

📝 Teacher's Note: Use everyday examples like sweating (skin excretion) and breathing out carbon dioxide (lung excretion) to help students relate to different excretory organs. Emphasize that excretion is essential for survival.

🎯 Exam Tip: Always mention all three organs (kidneys, skin, lungs) when defining excretory organs to score full marks.

Solution 2:
Answer: Carbon dioxide (CO2) and urine
In simple words: The main waste products our body makes are carbon dioxide gas (breathed out) and urine (filtered by kidneys).

📝 Teacher's Note: Connect this to daily experiences - students breathe out CO2 all the time and urinate regularly. This makes the concept more relatable and memorable.

🎯 Exam Tip: Write the chemical formula CO2 in brackets to show complete knowledge of the waste product.

Solution 3:
Answer: Ammonia is toxic in even small amounts and therefore it must be removed from the body. The urea cycle or the ornithine cycle, in the liver, involves the conversion of ammonia into urea. Then the urea is then transported to the kidneys where it is excreted.
In simple words: Ammonia is like poison to our body, so the liver quickly changes it into safer urea, which then goes to kidneys to be removed.

📝 Teacher's Note: Emphasize the liver's protective role as a detoxifier. Students often forget that waste processing happens before excretion. Use the analogy of a factory processing raw materials before disposal.

🎯 Exam Tip: Mention both names of the cycle (urea cycle OR ornithine cycle) and clearly state the sequence: ammonia → liver → urea → kidneys → excretion.

Solution 4:
Answer: Nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.
In simple words: Nephron is like a tiny filter in the kidney that sorts good stuff to keep from bad stuff to throw away as urine.

📝 Teacher's Note: Use the analogy of a coffee filter or water purifier that students see at home. Emphasize that each kidney has millions of these tiny filters working together.

🎯 Exam Tip: Always mention both structural AND functional unit, plus the three key processes: filtration, reabsorption, and excretion.

Solution 5:
Answer: [Diagram showing the human excretory system with labeled parts: Aorta, Renal artery, Renal vein, Left kidney, Right kidney, Ureter, Urinary bladder, Urethra]
In simple words: This diagram shows how blood flows to kidneys for cleaning, and how cleaned waste travels down tubes to the bladder for storage and removal.

📝 Teacher's Note: Point out the blood vessels (renal artery brings dirty blood, renal vein takes clean blood back) and the urine pathway (kidneys → ureters → bladder → urethra). Use hand gestures to trace the flow.

🎯 Exam Tip: When labeling excretory system diagrams, never confuse ureters (tubes from kidneys) with urethra (tube from bladder to outside).

Solution 6:
Answer: Dialysis is a process of separation of toxic substances from the blood stream through a membrane by kidney machine or artificial kidney.
In simple words: When kidneys fail, a special machine does the kidney's job of cleaning poison from blood using a filter membrane.

📝 Teacher's Note: Explain that dialysis patients need this treatment 2-3 times per week for several hours. This helps students understand the importance of healthy kidneys.

🎯 Exam Tip: Include the key terms "membrane," "artificial kidney," and "toxic substances" to show complete understanding of the dialysis process.

Solution 7:
Answer: 1. Ammonotelic. 2. Ureotelic. 3. Uricotelic. 4. Liver. 5. Nephron. 6. Urinary Bladder. 7. Glomerulus.
In simple words: These are fill-in-the-blank answers about different types of waste excretion and parts of the excretory system.

📝 Teacher's Note: Create memory aids: ammonotelic (ammonia), ureotelic (urea), uricotelic (uric acid). Connect each term to specific animal examples for better retention.

🎯 Exam Tip: Learn the three types of nitrogenous waste excretion (-telic words) as they frequently appear in competitive exams.

Solution 8:
Answer: 1. Vein 2. Heart 3. Haemoglobin 4. Glomerulus 5. Nerve 6. Brain
In simple words: These are answers for matching different body parts and their functions in various organ systems.

📝 Teacher's Note: Connect these terms to their broader systems - circulatory (vein, heart, haemoglobin), excretory (glomerulus), and nervous (nerve, brain). Show the interconnection between systems.

🎯 Exam Tip: When answering matching questions, double-check that each answer makes biological sense in context.

Solution 9:
Answer: 1. Separation and elimination of the metabolic nitrogenous wastes from the body is called excretion. 2. Nephron. 3. The cortex of kidney shows dotted appearance because it contains numerous complex structures called nephrons. 4. Formation of urine and osmoregulation are important functions of kidney.
In simple words: These answers explain what excretion is, what the kidney's basic unit is called, why kidney cortex looks dotted, and what kidneys do.

📝 Teacher's Note: Use a kidney model or diagram to show the cortex region and its dotted appearance. This visual aid helps students understand the nephron distribution.

🎯 Exam Tip: For kidney function questions, always mention both urine formation AND osmoregulation (water balance) for complete marks.

Solution 10:
Answer: 1. (a) kidney 2. (a) pigeon 3. (c) haematuria 4. (d) anuria 5. (d) Nothing will happen 6. (a) liver 7. (b) urease 8. (b) vitamin C 9. (b) liver 10. (c) nephron 11. (b) renal papilla
In simple words: These are multiple choice answers covering various aspects of excretory system including organs, diseases, and processes.

📝 Teacher's Note: Explain medical terms like haematuria (blood in urine) and anuria (no urine production) with their Greek/Latin roots to help students remember meanings.

🎯 Exam Tip: Learn the medical terminology for urinary disorders as they frequently appear in biology exams - haematuria, anuria, polyuria, etc.