Selina Class 7 Biology Solutions Chapter-5 Excretion in Humans
Introduction to Excretion in Humans
The study of human body systems becomes more interesting with Selina Class 7 Biology Solutions because each concept is explained in a simple and student-friendly manner. In Selina Solutions for ICSE board Chapter-5 Excretion in Humans focuses on how the body removes waste substances produced during different life processes. The chapter explains the importance of excretion, the structure of the human excretory system, functions of kidneys, formation of urine, and the role of skin and lungs in removing waste materials. These topics help students understand how the body maintains internal balance and stays healthy.
Find the Exercise-wise PDF of Selina Class 7 Biology Solutions chapter-5 Excretion in Humans.
Meaning and Importance of Excretion
The chapter begins with the meaning of excretion. Excretion is the process of removing harmful waste substances from the body. During respiration, digestion, and other metabolic activities, the body produces wastes such as carbon dioxide, urea, excess salts, and water. If these substances remain inside the body, they may become toxic and affect normal body functions.
The solutions explain the importance of excretion with practical examples so students can understand why waste removal is necessary for survival. Proper excretion keeps the blood clean and helps maintain balance in the body.
Human Excretory System
One of the main topics covered in this chapter is the human excretory system. Students learn about the important organs involved in excretion, including kidneys, ureters, urinary bladder, and urethra.
Kidneys
The kidneys are bean-shaped organs located on both sides of the backbone. Their main function is to filter blood and remove waste products from the body.
Ureters
The ureters are narrow tubes that carry urine from the kidneys to the urinary bladder.
Urinary Bladder
The urinary bladder stores urine temporarily before it is expelled from the body.
Urethra
The urethra is the tube through which urine passes out of the body.
The solutions describe these organs in a clear and systematic way, making it easier for students to learn their functions and remember them during examinations.
Structure and Function of Kidneys
The chapter explains the working of kidneys in detail. Blood carrying waste substances enters the kidneys through renal arteries. Inside the kidneys are tiny filtering units called nephrons. These nephrons help separate useful substances from harmful wastes.
Useful substances are reabsorbed into the blood, while waste materials and excess water form urine. The process of filtration and reabsorption is explained step by step in the solutions so students can understand urine formation without difficulty.
Composition of Urine
Another important concept discussed in this chapter is the composition of urine. Urine mainly contains water, urea, salts, and dissolved waste substances.
Urea is formed in the liver when proteins are broken down. This urea is carried through the blood to the kidneys for removal. The chapter also explains that urine colour and quantity may vary depending on water intake, food habits, and health conditions.
These practical examples help students relate scientific concepts to real-life observations.
Role of Lungs and Skin in Excretion
The chapter also explains that kidneys are not the only organs involved in excretion.
Role of Lungs
The lungs remove carbon dioxide and water vapour during exhalation. This process helps remove gaseous wastes from the body.
Role of Skin
The skin removes sweat through sweat glands. Sweat contains water, salts, and small amounts of urea. Sweating also helps regulate body temperature.
This section helps students understand that several organs work together to remove waste materials from the body.
Importance of Selina Solutions for ICSE Students
Selina solutions for this chapter provide detailed answers to textbook exercises, definitions, diagram-based questions, and short notes. Students preparing for school examinations benefit from accurate answers written according to the ICSE pattern.
Difficult biology terms are simplified for easy understanding. These solutions also improve answer-writing skills and help students revise important concepts quickly before exams.
Healthy Habits for a Proper Excretory System
The chapter highlights the importance of maintaining a healthy excretory system. Drinking enough water, maintaining personal hygiene, and eating a balanced diet support proper kidney function.
Students also learn that infections or disorders affecting excretory organs may disturb the removal of wastes from the body. This practical knowledge increases awareness about health and hygiene in daily life.
Conclusion
Chapter-5 Excretion in Humans helps students understand how the body removes harmful wastes and maintains internal balance. The chapter explains the functions of kidneys, lungs, skin, and other excretory organs in a clear and organised way. Regular practice of Selina exercise questions improves conceptual understanding, diagram practice, and exam preparation for ICSE students.