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The-Human-Excretory-System-for -Class 10 subject science
- 1. The Human Excretory System Wasteelimination and homeostasis
- 2. Introduction to Excretion WhyOur Bodies Need to Remove Waste Toxic Removal Eliminates harmful metabolic by-products like urea and ammonia Homeostasis Maintains fluid, electrolyte, and pH balance Water Regulation Controls body water levels and blood pressure Blood Purity Filters waste whilst retaining essential nutrients Excretion is vital for survival—without it, toxic substances would accumulate and disrupt cellular function
- 3. Overview of Human ExcretoryOrgans Primary Excretory System Kidneys: filter blood, produce urine Ureters: transport urine downward Urinary bladder: stores urine Urethra: expels urine from body Secondary Excretory Organs Lungs: remove CO₂ and water vapour Skin: excretes sweat (water, salts, urea) Liver: converts ammonia to urea Large intestine: eliminates solid waste
- 4. The Kidneys Structure, Nephrons,and Filtration 01 Filtration Blood enters glomerulus; water and small molecules filtered into Bowman's capsule 02 Reabsorption Useful substances (glucose, amino acids, water) returned to bloodstream via tubules 03 Secretion Additional waste (ions, toxins) actively transported into tubule 04 Excretion Concentrated urine flows to collecting duct, then to ureter Each kidney contains approximately 1 million nephrons—the functional filtering units that process about 180 litres of blood daily
- 5. The Ureters Transporting Urinefrom Kidneys to Bladder Structure Two muscular tubes, 25–30 cm long Lined with transitional epithelium Function Peristaltic contractions propel urine downward One-way valves prevent backflow Protection Prevents urine reflux to kidneys Maintains sterile pathway Urine moves through ureters in small spurts every 10–15 seconds via rhythmic muscle contractions
- 6. The Urinary Bladder Storageand Control Mechanisms Storage Capacity Holds 400–600 ml of urine Expandable muscular sac Stretch Receptors Detect fullness (150–200 ml) Send signals to brain Sphincter Control Internal sphincter (involuntary) External sphincter (voluntary) The detrusor muscle contracts during urination whilst sphincters relax—coordinated by the nervous system
- 7. The Urethra Final Pathwayfor Waste Elimination Length Variation Female: 4 cm shorter, external opening only Male: 20 cm, passes through prostate gland Function Expels urine from bladder to exterior Protected by mucous membrane lining Infection Risk Shorter female urethra increases UTI susceptibility Proper hygiene essential
- 8. Additional Excretory Processes Lungs,Skin, and Liver Lungs Remove: carbon dioxide, water vapour Process: gas exchange during respiration Volume: exhale ~200 ml water daily Skin Remove: water, salts, small amounts of urea Process: sweat gland secretion Function: thermoregulation and excretion Liver Remove: bile pigments, cholesterol Process: converts toxic ammonia to urea Role: detoxification and metabolism These organs work synergistically with kidneys to maintain metabolic balance and eliminate diverse waste products
- 9. Common Disorders ofthe Excretory System Kidney Stones Cause: mineral crystal formation Symptoms: severe pain, blood in urine, nausea Urinary Tract Infections (UTIs) Cause: bacterial infection Symptoms: burning sensation, frequent urination, fever Chronic Kidney Disease Cause: diabetes, hypertension, prolonged damage Symptoms: fatigue, swelling, reduced urine output Renal Failure Cause: sudden or gradual kidney function loss Symptoms: toxin build-up, requires dialysis or transplant Bladder Incontinence Cause: weakened sphincter muscles Symptoms: involuntary urine leakage Early detection through regular check-ups can prevent progression of many excretory system disorders
- 10. Maintaining Healthy KidneyFunction Prevention Strategies Stay Hydrated Drink 2–3 litres of water daily to flush toxins and prevent stone formation Balanced Diet Reduce salt, processed foods; increase fruits, vegetables, and whole grains Regular Exercise Maintain healthy weight and blood pressure through physical activity Monitor Health Regular blood pressure and blood sugar checks; annual kidney function tests Avoid Overmedication Limit NSAIDs and consult doctors before taking supplements Prevention is better than cure—simple lifestyle modifications can protect kidney health for life