Class 7 Science - ICSE-BIOLOGY
Excretion
The chapter 'Excretion' in Class 7 ICSE Biology introduces students to the vital life process of removing harmful nitrogenous waste products from the living body. Students will learn about the human excretory system, focusing on the kidneys, ureters, urinary bladder, and urethra, as well as the structure and function of a nephron. The chapter also covers the role of other excretory organs like the skin, lungs, and liver in maintaining internal balance, and touches upon excretion in plants. This topic is essential for ICSE board exams as it frequently features in diagram-based questions and structural identification.
Start Learning FreeKey Concepts
Excretion
The biological process of removing toxic metabolic wastes and excess substances from the body of living organisms.
Human Excretory System
Comprises a pair of bean-shaped kidneys, a pair of ureters, a urinary bladder, and a urethra that work together to filter blood and expel urine.
Nephron
The basic structural and functional filtration unit of the kidney responsible for forming urine.
Dialysis
An artificial medical process used to filter and purify the blood of patients whose kidneys have failed.
Excretion in Plants
Plants do not have specialized excretory organs; instead, they eliminate wastes through transpiration, shedding of leaves, and storing waste as resins or gums.
Important Formulas
Board Exam Info
In ICSE Biology examinations, this chapter typically carries about 5 to 8 marks. Questions frequently include labeling diagrams of the human excretory system or a nephron, defining key terms, and distinguishing between excretion and egestion.
Frequently Asked Questions
What is the difference between excretion and egestion?
Excretion is the removal of metabolic waste produced inside body cells, whereas egestion is the removal of undigested food from the alimentary canal.
What is the main function of the kidneys?
The main function of the kidneys is to filter blood to remove urea, excess water, and mineral salts, forming urine to maintain body fluid balance.
How do plants get rid of their waste products?
Plants release oxygen during photosynthesis and carbon dioxide during respiration through stomata, and store other wastes in leaves, bark, or fruits that eventually fall off.
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